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Sample records for mealybug wilt disease

  1. Perception of Mealybug Wilt Effect and Management among ...

    African Journals Online (AJOL)

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    College of Agriculture and Natural Sciences (CANS). University of Cape Coast ... vectors and their ant symbionts. Keywords: Mealybug Wilt Effect, Mealybug Management, Mealybug in Pineapple,. Mealybug ... and Tafe in the Volta Region, is a boost for cottage industrialization (Ministry of Food and Agriculture [MoFA], 2006; ...

  2. Transmission of Pineapple Mealybug Wilt-Associated Virus by Two Species of Mealybug (Dysmicoccus spp.).

    Science.gov (United States)

    Sether, D M; Ullman, D E; Hu, J S

    1998-11-01

    ABSTRACT Closterovirus-like particles associated with mealybug wilt of pineapple were acquired and transmitted by the pink pineapple mealybug, Dysmicoccus brevipes, and the gray pineapple mealybug, D. neobrevipes. Mealybugs acquired pineapple mealybug wilt-associated virus (PMWaV) from infected pineapple plants or detached leaves. The virus was detected in plants by tissue blot immunoassay and confirmed by immunosorbent electron microscopy. Plants exposed to mealybugs reared on PMWaV-free pineapple tissue remained uninfected. The presence of ants was correlated with an increased rate of virus spread when caged with D. brevipes. All stages of D. neobrevipes acquired PMWaV, although vector efficiency decreased significantly in older adult females. The probability of a single third-instar immature transmitting the virus was 0.04. Both species of mealybug acquired and transmitted PMWaV from infected pineapple material that had been clonally propagated for decades, and both species acquired PMWaV from sources previously infected with the virus by the other mealybug species.

  3. A highly sensitive single-tube nested PCR assay for the detection of Pineapple mealybug wilt associated virus-2 (PMWaV-2)

    Science.gov (United States)

    An assay was developed for the detection of Pineapple mealybug wilt associated virus-2 (PMWaV-2), an important factor in the etiology of mealybug wilt of pineapple. The assay combines reverse transcription of RNA isolated from pineapple with a specific and very sensitive, single, closed-tube nested ...

  4. KEBERADAAN DYSMICOCCUS BREVIPES (COCKERELL (HEMIPTERA: PSEUDOCOCCIDAE SEBAGAI VEKTOR PINEAPPLE MEALYBUG WILT-ASSOCIATED VIRUS (PMWAV PADA TANAMAN NANAS

    Directory of Open Access Journals (Sweden)

    Dewi Sartiami

    2006-04-01

    Full Text Available Mealybug can almost be found in all pineapple fields (Ananas comosus (Linnaeus. The insect is known to be a vector of Pineapple Mealybug wilt-associated Virus (PMWaV. The insect samples taken from pineapple in Bunihayu, Jalancagak, Subang, West Java, were identified in laboratory. Mealybug-ant symbionts were also taken. The ability of this ant to carry the mealybugs from colony reared on kabocha (Cucurbita maxima to pineapple was also tested at green house level. Only one spesies of mealybug was found on pineapple, i.e. Dysmicoccus brevipes (Cockerell (Hemiptera: Pseudococcidae. The mealybugs were found to colonize root, basal of stem and the leaf. Eight ant species were found to be associated with mealybug. There are four species belongs to Pseudolasius genera, two species Cardiocondyla genera, Paratrechina sp. and Dorylus sp. Paratrechina sp. showed the ability to carry D. brevipes from kabocha population to pineapple. Therefore the ants should also be controlled in the total management of PMWav.

  5. Effect of selected essential oil plants on bacterial wilt disease ...

    African Journals Online (AJOL)

    Objective: Bacterial wilt disease caused by Ralstonia solanacearum is a major constrain to production of potatoes (Solanum tuberosum). Control of bacterial wilt is very difficult as there are no effective curative chemicals. This study was aimed at investigating the potential roles of essential oil plants in control of the disease.

  6. Banana Xanthomonas wilt: a review of the disease, management ...

    African Journals Online (AJOL)

    ... a review of the disease, management strategies and future research directions. ... Plants are infected either by insects through the inflorescence or by ... wilt is not fully understood but its impact on food security in the region is very significant.

  7. Disjunct population of redbay ambrosia beetle and laurel wilt disease discovered in Mississippi

    Science.gov (United States)

    J.J. Riggins; M. Hughes; J.A. Smith; R. Chapin

    2011-01-01

    Laurel wilt is an aggressive, non-native vascular wilt disease of redbay trees (Persea borbonia), sassafras (Sassafras albidum), and other plants within the Lauraceae family. The laurel wilt pathogen, (Raffaelea lauricola), is vectored by the redbay ambrosia beetle (Xyleborus glabratus), which...

  8. Mathematical analysis of dynamic spread of Pine Wilt disease.

    Science.gov (United States)

    Dimitrijevic, D D; Bacic, J

    2013-01-01

    Since its detection in Portugal in 1999, the pinewood nematode Bursaphelenchus xylophilus (Steiner and Buhrer), a causal agent of Pine Wilt Disease, represents a threat to European forestry. Significant amount of money has been spent on its monitoring and eradication. This paper presents mathematical analysis of spread of pine wilt disease using a set of partial differential equations with space (longitude and latitude) and time as parameters of estimated spread of disease. This methodology can be used to evaluate risk of various assumed entry points of disease and make defense plans in advance. In case of an already existing outbreak, it can be used to draw optimal line of defense and plan removal of trees. Optimization constraints are economic loss of removal of susceptible trees as well as budgetary constraints of workforce cost.

  9. The phloem-sap feeding mealybug (Ferrisia virgata carries 'Candidatus Liberibacter asiaticus' populations that do not cause disease in host plants.

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    Marco Pitino

    Full Text Available 'Candidatus Liberibacter asiaticus' (Las is the primary causal agent of huanglongbing (HLB, the most devastating disease of citrus worldwide. There are three known insect vectors of the HLB-associated bacteria, and all are members of the Hemiptera: Diaphorina citri (Psyllidae, Trioza erytreae (Triozidae, and Cacopsylla (Psylla citrisuga (Psyllidae. In this study, we found that another hemipteran, the striped mealybug Ferrisia virgata (Cockerell (Hemiptera: Pseudococcidae, was able to acquire and retain Las bacteria. The bacterial titers were positively correlated with the feeding acquisition time on Las-infected leaf discs, with a two-weeks feeding period resulting in Ct values ranging from 23.1 to 36.1 (8.24 × 10(7 to 1.07 × 10(4 Las cells per mealybug. We further discovered that the prophage/phage populations of Las in the mealybugs were different from those of Las in psyllids based on Las prophage-specific molecular markers: infected psyllids harbored the Las populations with prophage/phage FP1 and FP2, while infected mealybugs carried the Las populations with the iFP3 being the dominant prophage/phage. As in the psyllids, Las bacteria were shown to move through the insect gut wall to the salivary glands after being ingested by the mealybug based on a time-course quantitative polymerase chain reaction (qPCR assay of the dissected digestive systems. However, Las populations transmitted by the mealybugs did not cause disease in host plants. This is the first evidence of genetic difference among Las populations harbored by different insect vectors and difference among Las populations with respect to whether or not they cause disease in host plants.

  10. Metabolomics of tomato xylem sap during bacterial wilt reveals Ralstonia solanacearum produces abundant putrescine, a metabolite that accelerates wilt disease

    NARCIS (Netherlands)

    Lowe-Power, Tiffany M.; Hendrich, Connor G.; Roepenack-Lahaye, von Edda; Li, Bin; Wu, Dousheng; Mitra, Raka; Dalsing, Beth L.; Ricca, Patrizia; Naidoo, Jacinth; Cook, David; Jancewicz, Amy; Masson, Patrick; Thomma, Bart; Lahaye, Thomas; Michael, Anthony J.; Allen, Caitilyn

    2018-01-01

    Ralstonia solanacearum thrives in plant xylem vessels and causes bacterial wilt disease despite the low nutrient content of xylem sap. We found that R. solanacearum manipulates its host to increase nutrients in tomato xylem sap, enabling it to grow better in sap from infected plants than in sap from

  11. Identification and Chacterization of new strains of Enterobacter spp. causing Mulberry (Morus alba) wilt disease in China

    Science.gov (United States)

    A new mulberry wilt disease (MWD) was recently identified in Hangzhou, Zhejiang province, China. Typical symptoms of the disease are dark brown discolorations in vascular tissues, leaf wilt, defoliation, and tree decline. Unlike the bacterial wilt disease caused by Ralstonia solanacearum, the leaf w...

  12. Progression and Impact of Laurel Wilt Disease within Redbay and Sassafras Populations in Southeast Georgia

    Science.gov (United States)

    R. Scott Cameron; James Hanula; Stephen Fraedrich; Chip Bates

    2015-01-01

    Laurel wilt disease (LWD), caused by the fungus Raffaelea lauricola and transmitted by Xyleborus glabratus (Redbay Ambrosia Beetle [RAB]), has killed millions of Persea borbonia (Redbay) trees throughout the southeastern Coastal Plain. Laurel wilt also has been...

  13. The economics of managing Verticillium wilt, an imported disease in California lettuce

    OpenAIRE

    Carroll, Christine L; Carter, Colin A; Goodhue, Rachael E; Lin Lawell, C.-Y. Cynthia; Subbarao, Krishna V

    2017-01-01

    Verticillium dahliae is a soilborne fungus that is introduced to the soil via infested spinach seeds and that causes lettuce to be afflicted with Verticillium wilt. This disease has spread rapidly through the Salinas Valley, the prime lettuce production region of California. Verticillium wilt can be prevented or controlled by the grower by fumigating, planting broccoli, or not planting spinach. Because these control options require long-term investment for future gain, renters might not take ...

  14. The economics of managing Verticillium wilt, an imported disease in California lettuce

    Directory of Open Access Journals (Sweden)

    Christine L. Carroll

    2017-09-01

    Full Text Available Verticillium dahliae is a soilborne fungus that is introduced to the soil via infested spinach seeds and that causes lettuce to be afflicted with Verticillium wilt. This disease has spread rapidly through the Salinas Valley, the prime lettuce production region of California. Verticillium wilt can be prevented or controlled by the grower by fumigating, planting broccoli, or not planting spinach. Because these control options require long-term investment for future gain, renters might not take the steps needed to control Verticillium wilt. Verticillium wilt can also be prevented or controlled by a spinach seed company through testing and cleaning the spinach seeds. However, seed companies are unwilling to test or clean spinach seeds, as they are not affected by this disease. We discuss our research on the externalities that arise with renters, and between seed companies and growers, due to Verticillium wilt. These externalities have important implications for the management of Verticillium wilt in particular, and for the management of diseases in agriculture in general.

  15. Metabolomics of tomato xylem sap during bacterial wilt reveals Ralstonia solanacearum produces abundant putrescine, a metabolite that accelerates wilt disease.

    Science.gov (United States)

    Lowe-Power, Tiffany M; Hendrich, Connor G; von Roepenack-Lahaye, Edda; Li, Bin; Wu, Dousheng; Mitra, Raka; Dalsing, Beth L; Ricca, Patrizia; Naidoo, Jacinth; Cook, David; Jancewicz, Amy; Masson, Patrick; Thomma, Bart; Lahaye, Thomas; Michael, Anthony J; Allen, Caitilyn

    2018-04-01

    Ralstonia solanacearum thrives in plant xylem vessels and causes bacterial wilt disease despite the low nutrient content of xylem sap. We found that R. solanacearum manipulates its host to increase nutrients in tomato xylem sap, enabling it to grow better in sap from infected plants than in sap from healthy plants. Untargeted GC/MS metabolomics identified 22 metabolites enriched in R. solanacearum-infected sap. Eight of these could serve as sole carbon or nitrogen sources for R. solanacearum. Putrescine, a polyamine that is not a sole carbon or nitrogen source for R. solanacearum, was enriched 76-fold to 37 µM in R. solanacearum-infected sap. R. solanacearum synthesized putrescine via a SpeC ornithine decarboxylase. A ΔspeC mutant required ≥ 15 µM exogenous putrescine to grow and could not grow alone in xylem even when plants were treated with putrescine. However, co-inoculation with wildtype rescued ΔspeC growth, indicating R. solanacearum produced and exported putrescine to xylem sap. Intriguingly, treating plants with putrescine before inoculation accelerated wilt symptom development and R. solanacearum growth and systemic spread. Xylem putrescine concentration was unchanged in putrescine-treated plants, so the exogenous putrescine likely accelerated disease indirectly by affecting host physiology. These results indicate that putrescine is a pathogen-produced virulence metabolite. © 2017 Society for Applied Microbiology and John Wiley & Sons Ltd.

  16. Effect Of Salinization On Fusarium Wilt Disease In Tomato Plant

    International Nuclear Information System (INIS)

    Ahmed, B.M.; Fath El-Bab, T.S.

    2013-01-01

    Salinization of soils or waters is one of the serious environmental problems in agriculture. It is necessary to determine the environmental factors under which the plants give higher yields and better quality to solve this problem. The problem of salinity is characterized by disruption in the physiological processes in plant which lead to shorting in growth and decrease in yield. The study was carried out to control fusarium disease in tomato plant irrigated with salt water (500, 1500, 15000, 45000 and 100000 ppm). These treatments lead to excess in malic and citric acids i.e. from 21 mmol/g fresh weight in control to 38.8 mmol/g fresh weight at 100000 ppm for citric acid while for malic acid, the value was increased from 1.4 mmol/g fresh weight for control to 2.1 mmol/g fresh weight. The excess of malic and citric acids lead to increase in acidity and vitamin C in tomato fruits. On the other side, the plant may adapt to this stress by increasing its proline content from 0.59 µmol/g fresh weight to 6.56 µmol/g fresh weight at 100000 and abscisic acid from 0.49 µmol/g fresh weight to 20.7 µmol/g fresh weight. The results showed that the fusarium fungal growth was observed till 100000 ppm but did not form sclerotia spores at 45000 ppm. On the other hand, the electrical conductivity was found to be 0.46, 2.3, 23.1, 69.2 and 153.8 dS/m for salinity levels of 500, 1500, 15000, 45000 and 100000 ppm, respectively. This study aimed to control the fusarium wilt disease by irrigating the plant with water has high salinity

  17. Hydrogen Peroxide- and Nitric Oxide-mediated Disease Control of Bacterial Wilt in Tomato Plants

    Directory of Open Access Journals (Sweden)

    Jeum Kyu Hong

    2013-12-01

    Full Text Available Reactive oxygen species (ROS generation in tomato plants by Ralstonia solanacearum infection and the role of hydrogen peroxide (H₂O₂ and nitric oxide in tomato bacterial wilt control were demonstrated. During disease development of tomato bacterial wilt, accumulation of superoxide anion (O₂− and H₂O₂ was observed and lipid peroxidation also occurred in the tomato leaf tissues. High doses of H₂O₂and sodium nitroprusside (SNP nitric oxide donor showed phytotoxicity to detached tomato leaves 1 day after petiole feeding showing reduced fresh weight. Both H₂O₂and SNP have in vitro antibacterial activities against R. solanacearum in a dose-dependent manner, as well as plant protection in detached tomato leaves against bacterial wilt by 10⁶ and 10⁷ cfu/ml of R. solanacearum. H₂O₂- and SNP-mediated protection was also evaluated in pots using soil-drench treatment with the bacterial inoculation, and relative ‘area under the disease progressive curve (AUDPC’ was calculated to compare disease protection by H₂O₂ and/or SNP with untreated control. Neither H₂O₂ nor SNP protect the tomato seedlings from the bacterial wilt, but H₂O₂+ SNP mixture significantly decreased disease severity with reduced relative AUDPC. These results suggest that H₂O₂ and SNP could be used together to control bacterial wilt in tomato plants as bactericidal agents.

  18. Bio-fertilizer application induces soil suppressiveness against Fusarium wilt disease by reshaping the soil microbiome

    NARCIS (Netherlands)

    Wu, Xiong; Guo, Sai; Jousset, Alexandre; Zhao, Qingyun; Wu, Huasong; Li, Rong; Kowalchuk, George A.; Shen, Qirong

    2017-01-01

    Fusarium wilt disease is a growing problem in agriculture systems. Application of bio-fertilizers containing beneficial microbes represents a promising disease control strategy. However, the mechanisms underlying disease suppression remain elusive. Here, in order to assess the importance of direct

  19. The history and epidemiology of Cape St Paul wilt disease of ...

    African Journals Online (AJOL)

    The history of the spread of the Cape St. Paul Wilt (lethal yellowing) disease of coconut in Ghana is presented. Epidemiological studies showed that the disease starts slowly, then progresses (accelerate) rapidly before levelling off. In a farm, the disease first appears randomly on single trees, foci then develop around these ...

  20. Rosemary wilting disease and its management by soil solarization ...

    African Journals Online (AJOL)

    Three fungal pathogens including Phytophthora citrophthora, Rhizoctonia solani and Fusarium oxysporum were determined, whereas Helicotylenchus spp. was also associated. Pathogenicity tests proved that they were wilting pathogens, although P. citrophthora was the major pathogen in the field and glasshouses. This is ...

  1. Laurel wilt in avocado: Review of an emerging disease

    Science.gov (United States)

    aurel wilt, caused by the vascular fungus Raffaelea lauricola, is transmitted by the redbay ambrosia beetle, Xyleborus glabratus, and affects many plants in the family Lauraceae. It was introduced into the United States around 2002 through infested packing material arriving in Georgia. In Florida, t...

  2. Effect of selected essential oil plants on bacterial wilt disease ...

    African Journals Online (AJOL)

    SARAH

    2014-03-25

    Mar 25, 2014 ... March 2014. Published online at www.m.elewa.org on 30thJune 2014. ... Control of bacterial wilt is very difficult as there are no effective curative chemicals. ..... by Dr. S.T. Kariuki of Egerton University, Biological. Science ...

  3. Detection of laurel wilt disease in avocado using low altitude aerial imaging.

    Science.gov (United States)

    de Castro, Ana I; Ehsani, Reza; Ploetz, Randy C; Crane, Jonathan H; Buchanon, Sherrie

    2015-01-01

    Laurel wilt is a lethal disease of plants in the Lauraceae plant family, including avocado (Persea americana). This devastating disease has spread rapidly along the southeastern seaboard of the United States and has begun to affect commercial avocado production in Florida. The main objective of this study was to evaluate the potential to discriminate laurel wilt-affected avocado trees using aerial images taken with a modified camera during helicopter surveys at low-altitude in the commercial avocado production area. The ability to distinguish laurel wilt-affected trees from other factors that produce similar external symptoms was also studied. RmodGB digital values of healthy trees and laurel wilt-affected trees, as well as fruit stress and vines covering trees were used to calculate several vegetation indices (VIs), band ratios, and VI combinations. These indices were subjected to analysis of variance (ANOVA) and an M-statistic was performed in order to quantify the separability of those classes. Significant differences in spectral values among laurel wilt affected and healthy trees were observed in all vegetation indices calculated, although the best results were achieved with Excess Red (ExR), (Red-Green) and Combination 1 (COMB1) in all locations. B/G showed a very good potential for separate the other factors with symptoms similar to laurel wilt-affected trees, such as fruit stress and vines covering trees, from laurel wilt-affected trees. These consistent results prove the usefulness of using a modified camera (RmodGB) to discriminate laurel wilt-affected avocado trees from healthy trees, as well as from other factors that cause the same symptoms and suggest performing the classification in further research. According to our results, ExR and B/G should be utilized to develop an algorithm or decision rules to classify aerial images, since they showed the highest capacity to discriminate laurel wilt-affected trees. This methodology may allow the rapid detection

  4. Detection of laurel wilt disease in avocado using low altitude aerial imaging.

    Directory of Open Access Journals (Sweden)

    Ana I de Castro

    Full Text Available Laurel wilt is a lethal disease of plants in the Lauraceae plant family, including avocado (Persea americana. This devastating disease has spread rapidly along the southeastern seaboard of the United States and has begun to affect commercial avocado production in Florida. The main objective of this study was to evaluate the potential to discriminate laurel wilt-affected avocado trees using aerial images taken with a modified camera during helicopter surveys at low-altitude in the commercial avocado production area. The ability to distinguish laurel wilt-affected trees from other factors that produce similar external symptoms was also studied. RmodGB digital values of healthy trees and laurel wilt-affected trees, as well as fruit stress and vines covering trees were used to calculate several vegetation indices (VIs, band ratios, and VI combinations. These indices were subjected to analysis of variance (ANOVA and an M-statistic was performed in order to quantify the separability of those classes. Significant differences in spectral values among laurel wilt affected and healthy trees were observed in all vegetation indices calculated, although the best results were achieved with Excess Red (ExR, (Red-Green and Combination 1 (COMB1 in all locations. B/G showed a very good potential for separate the other factors with symptoms similar to laurel wilt-affected trees, such as fruit stress and vines covering trees, from laurel wilt-affected trees. These consistent results prove the usefulness of using a modified camera (RmodGB to discriminate laurel wilt-affected avocado trees from healthy trees, as well as from other factors that cause the same symptoms and suggest performing the classification in further research. According to our results, ExR and B/G should be utilized to develop an algorithm or decision rules to classify aerial images, since they showed the highest capacity to discriminate laurel wilt-affected trees. This methodology may allow the

  5. How to Identify and Manage Pine Wilt Disease and Treat Wood Products Infested by the Pinewood Nematodes

    Science.gov (United States)

    Jim Hanson; Michelle Cram

    2004-01-01

    Pine wilt is a disease of pine (Pinus spp.) caused by the pinewood nematode, Bursaphelenchus xylophilus. The pinewood nematode is native to North America and is not considered a primary pathogen of native pines, but is the cause of pine wilt in some non-native pines. In countries where the pinewood nematode has been introduced, such as Japan and China, pine wilt is an...

  6. First report of laurel wilt disease caused by Raffaelea lauricola on pondspice in Florida

    Science.gov (United States)

    M. Hughes; J.A. Smith; A.E. Mayfield III; M.C. Minno; K. Shin

    2011-01-01

    Laurel wilt is a fungal vascular disease of redbay (Persea borbonia (L.) Spreng) and other plants in the family Lauraceae in the southeastern United States (1). The disease is caused by Raffaelea lauricola T. C. Harr., Fraedrich & Aghayeva, which is vectored by the exotic redbay ambrosia beetle (Xyleborus glabratus...

  7. Refining a major QTL controlling spotted wilt disease resistance in cultivated peanut (Arachis hypogaea L.)and evaluating its contribution to the resistance variations in peanut germplasm

    Science.gov (United States)

    Spotted wilt, caused by tomato spotted wilt virus (TSWV), has been one of major diseases in cultivated peanut grown in the southeastern United States (US) since 1990. Previously a major quantitative trait locus (QTL) controlling spotted wilt disease resistance was mapped to an interval of 2.55 cent...

  8. Regeneration of different plant functional types in a Masson pine forest following pine wilt disease.

    Science.gov (United States)

    Hu, Guang; Xu, Xuehong; Wang, Yuling; Lu, Gao; Feeley, Kenneth J; Yu, Mingjian

    2012-01-01

    Pine wilt disease is a severe threat to the native pine forests in East Asia. Understanding the natural regeneration of the forests disturbed by pine wilt disease is thus critical for the conservation of biodiversity in this realm. We studied the dynamics of composition and structure within different plant functional types (PFTs) in Masson pine forests affected by pine wilt disease (PWD). Based on plant traits, all species were assigned to four PFTs: evergreen woody species (PFT1), deciduous woody species (PFT2), herbs (PFT3), and ferns (PFT4). We analyzed the changes in these PFTs during the initial disturbance period and during post-disturbance regeneration. The species richness, abundance and basal area, as well as life-stage structure of the PFTs changed differently after pine wilt disease. The direction of plant community regeneration depended on the differential response of the PFTs. PFT1, which has a higher tolerance to disturbances, became dominant during the post-disturbance regeneration, and a young evergreen-broad-leaved forest developed quickly after PWD. Results also indicated that the impacts of PWD were dampened by the feedbacks between PFTs and the microclimate, in which PFT4 played an important ecological role. In conclusion, we propose management at the functional type level instead of at the population level as a promising approach in ecological restoration and biodiversity conservation.

  9. Recent Trends in Control Methods for Bacterial Wilt Diseases Caused by Ralstonia solanacearum

    Science.gov (United States)

    Yuliar; Nion, Yanetri Asi; Toyota, Koki

    2015-01-01

    Previous studies have described the development of control methods against bacterial wilt diseases caused by Ralstonia solanacearum. This review focused on recent advances in control measures, such as biological, physical, chemical, cultural, and integral measures, as well as biocontrol efficacy and suppression mechanisms. Biological control agents (BCAs) have been dominated by bacteria (90%) and fungi (10%). Avirulent strains of R. solanacearum, Pseudomonas spp., Bacillus spp., and Streptomyces spp. are well-known BCAs. New or uncommon BCAs have also been identified such as Acinetobacter sp., Burkholderia sp., and Paenibacillus sp. Inoculation methods for BCAs affect biocontrol efficacy, such as pouring or drenching soil, dipping of roots, and seed coatings. The amendment of different organic matter, such as plant residue, animal waste, and simple organic compounds, have frequently been reported to suppress bacterial wilt diseases. The combined application of BCAs and their substrates was shown to more effectively suppress bacterial wilt in the tomato. Suppression mechanisms are typically attributed to the antibacterial metabolites produced by BCAs or those present in natural products; however, the number of studies related to host resistance to the pathogen is increasing. Enhanced/modified soil microbial communities are also indirectly involved in disease suppression. New promising types of control measures include biological soil disinfection using substrates that release volatile compounds. This review described recent advances in different control measures. We focused on the importance of integrated pest management (IPM) for bacterial wilt diseases. PMID:25762345

  10. Ambrosia beetle communities in forest and agriculture ecosystems with laurel wilt disease

    Science.gov (United States)

    The invasive redbay ambrosia beetle, Xyleborus glabratus, is an exotic wood-boring pest first detected in 2002 near Savannah, Georgia. The beetle’s dominant fungal symbiont, Raffaelea lauricola, is the pathogen that causes laurel wilt, a lethal disease of trees in the family Lauraceae. Redbay ambro...

  11. Cape Saint Paul Wilt Disease of coconut in Ghana: surveillance and management of disease spread

    Directory of Open Access Journals (Sweden)

    Nkansah-Poku Joe

    2009-03-01

    Full Text Available The Cape Saint Paul Wilt Disease (CSPWD, a lethal-yellowing type disease of coconut has been in Ghana since 1932. Aerial and/or ground surveys were undertaken to assess the current status of the disease spread. The survey showed that the spread of the disease for the past 5 years has mainly been the expansion of existing foci. However, new outbreaks were identified at Glidzi in the Volta, Bawjiase and Efutu Breman in Central regions. After the resurgence in the Volta region in 1995, the Woe-Tegbi-Dzelukope corridor has remained endemic, but less aggressive. Pockets of healthy groves remain along all the coastline and inland of known disease zones. Eradication of diseased palms at Ampain focus lying just about 60 km to the Ivorian border, and disease situations on new replanting with MYD × VTT hybrid are discussed.

  12. Controlling fusarium wilt disease in melon(cucumis melo L.) using tilllered onion bulb extract

    International Nuclear Information System (INIS)

    Yushu, Z.; Guo, Q.; Xuezheng, W.; Yanan, Z.; Yuting, Li.

    2017-01-01

    Melon wilt disease is a soil-borne disease caused by Fusarium oxysporum f. sp. niveum. This disease incur of the heavy economic loss in melon crops. To decrease damage to melons, many control methods have been developed. However, many of the current control methods have limitations and disadvantages. For example, fungicides may cause health concerns for both humans and the environment due to high toxin content and the presence of residues. Therefore, biological control methods that reduce or eliminate the risk of environmental contamination and threats to human health are urgently needed to solve these issues and to protect melon crops from wilt disease.In this research, we assessed the efficacy of tillered onion bulb extract (TOE) for biocontrol of melon wilt disease in melon. Different concentrations of the TOE have been shown to have inhibitory effects on Fusariumspore germination and growth, pathogenic bacterial biomass, and fungal sporulation, with increased inhibitory effects at higher TOE concentrations. In melon wilt disease, concentrations of TOE greater than 250 mg/mL produced the highest protective effects in both susceptible and resistant melon cultivars. The disease index in resistant varieties was 18%, and the disease control effect was 63.51%, while the disease index in susceptible varieties was 21.41%, and the disease control effect reached 65.96%. These values indicate stronger control effects than those achieved using 40% Ning WP melon blight. High concentrations (over 500 mg/mL) of TOE had strong inhibitory effects on melon seed germination and the activity of protective enzymes in melon cultivars. (author)

  13. Effect of fusarium wilt disease on seed yield of advance lentil genotypes

    International Nuclear Information System (INIS)

    Sarwar, G.; Asghar, M.J.; Abbas, G.; Akhtar, K.P.

    2014-01-01

    Wilt caused by Fusarium oxysporum is considered as the most damaging soil disease of lentil. Current study was carried out to see the effect of Fusarium wilt disease on seed yield of advance lentil genotypes in wilt sick plot. Fourteen entries were tested in national yield uniform trial (NUYT), 11 in adaptation yield trial (AYT), 15 in advance line yield trial-I (ALYT-I), 12 in advance line yield trial-II (ALYT-II) and 25 in preliminary yield trial (PYT) along with standard check. Mean seed yields of 891.04, 1281.78, 1153.81, 1080.04 and 789.45 kg ha/sup -1/were observed in NUYT, AYT, ALYT-I, ALYT-II and PYT, respectively. The average disease intensity in various trials was more than 30%. Disease severity was less than 10% in nine genotypes. This was also confirmed by high negative values of their losses over check. Out of these, the genotypes, 03501, NL 96625, NL 66184, NL 66106 and NL 31742/03 produced highest seed yield of 2945 kg ha/sup -1/, 2667 kg ha/sup -1/, 2490 kg ha/sup -1/,2390 kg ha/sup -1/and 2691 kg ha/sup -1/ respectively. The higher yield may be attributed to inbuilt resistance against such a drastic disease. Overall, seed yield and disease incidence were negatively correlated in all yield trials. The genotypes under severe wilt attack produced no seed yield. It is clear from this study that resistance/tolerance is available in lentil that can be selected based on high yield potential along with minimum yield losses for further breeding. (author)

  14. Differential Control Efficacies of Vitamin Treatments against Bacterial Wilt and Grey Mould Diseases in Tomato Plants

    Directory of Open Access Journals (Sweden)

    Jeum Kyu Hong

    2016-10-01

    Full Text Available Bacterial wilt and grey mould in tomato plants are economically destructive bacterial and fungal diseases caused by Ralstonia solanacearum and Botrytis cinerea, respectively. Various approaches including chemical and biological controls have been attempted to arrest the tomato diseases so far. In this study, in vitro growths of bacterial R. solanacearum and fungal B. cinerea were evaluated using four different vitamins including thiamine (vitamin B1, niacin (vitamin B3, pyridoxine (vitamin B6, and menadione (vitamin K3. In planta efficacies of the four vitamin treatments on tomato protection against both diseases were also demonstrated. All four vitamins showed different in vitro antibacterial activities against R. solanacearum in dose-dependent manners. However, treatment with 2 mM thiamine was only effective in reducing bacterial wilt of detached tomato leaves without phytotoxicity under lower disease pressure (10⁶ colony-forming unit [cfu]/ml. Treatment with the vitamins also differentially reduced in vitro conidial germination and mycelial growth of B. cinerea. The four vitamins slightly reduced the conidial germination, and thiamine, pyridoxine and menadione inhibited the mycelial growth of B. cinerea. Menadione began to drastically suppress the conidial germination and mycelial growth by 5 and 0.5 mM, respectively. Grey mould symptoms on the inoculated tomato leaves were significantly reduced by pyridoxine and menadione pretreatments one day prior to the fungal challenge inoculation. These findings suggest that disease-specific vitamin treatment will be integrated for eco-friendly management of tomato bacterial wilt and grey mould.

  15. Differential Control Efficacies of Vitamin Treatments against Bacterial Wilt and Grey Mould Diseases in Tomato Plants.

    Science.gov (United States)

    Hong, Jeum Kyu; Kim, Hyeon Ji; Jung, Heesoo; Yang, Hye Ji; Kim, Do Hoon; Sung, Chang Hyun; Park, Chang-Jin; Chang, Seog Won

    2016-10-01

    Bacterial wilt and grey mould in tomato plants are economically destructive bacterial and fungal diseases caused by Ralstonia solanacearum and Botrytis cinerea , respectively. Various approaches including chemical and biological controls have been attempted to arrest the tomato diseases so far. In this study, in vitro growths of bacterial R. solanacearum and fungal B. cinerea were evaluated using four different vitamins including thiamine (vitamin B1), niacin (vitamin B3), pyridoxine (vitamin B6), and menadione (vitamin K3). In planta efficacies of the four vitamin treatments on tomato protection against both diseases were also demonstrated. All four vitamins showed different in vitro antibacterial activities against R. solanacearum in dose-dependent manners. However, treatment with 2 mM thiamine was only effective in reducing bacterial wilt of detached tomato leaves without phytotoxicity under lower disease pressure (10 6 colony-forming unit [cfu]/ml). Treatment with the vitamins also differentially reduced in vitro conidial germination and mycelial growth of B. cinerea . The four vitamins slightly reduced the conidial germination, and thiamine, pyridoxine and menadione inhibited the mycelial growth of B. cinerea . Menadione began to drastically suppress the conidial germination and mycelial growth by 5 and 0.5 mM, respectively. Grey mould symptoms on the inoculated tomato leaves were significantly reduced by pyridoxine and menadione pretreatments one day prior to the fungal challenge inoculation. These findings suggest that disease-specific vitamin treatment will be integrated for eco-friendly management of tomato bacterial wilt and grey mould.

  16. Occurrence of Root Rot and Vascular Wilt Diseases in Roselle (Hibiscus sabdariffa L.) in Upper Egypt

    Science.gov (United States)

    Hassan, Naglaa; Shimizu, Masafumi

    2014-01-01

    Roselle (Hibiscus sabdariffa L.) family Malvaceae is an important crop used in food, cosmetics and pharmaceutics industries. Roselle is cultivated mainly in Upper Egypt (Qena and Aswan governorates) producing 94% of total production. Root rot disease of roselle is one of the most important diseases that attack both seedlings and adult plants causing serious losses in crop productivity and quality. The main objective of the present study is to identify and characterize pathogens associated with root rot and wilt symptoms of roselle in Qena, Upper Egypt and evaluate their pathogenicity under greenhouse and field condition. Fusarium oxysporum, Macrophomina phaseolina, Fusarium solani, Fusarium equiseti and Fusarium semitectum were isolated from the natural root rot diseases in roselle. All isolated fungi were morphologically characterized and varied in their pathogenic potentialities. They could attack roselle plants causing damping-off and root rot/wilt diseases in different pathogenicity tests. The highest pathogenicity was caused by F. oxysporum and M. phaseolina followed by F. solani. The least pathogenic fungi were F. equiseti followed by F. semitectum. It obviously noted that Baladi roselle cultivar was more susceptible to infection with all tested fungi than Sobhia 17 under greenhouse and field conditions. This is the first report of fungal pathogens causing root rot and vascular wilt in roselle in Upper Egypt. PMID:24808737

  17. Occurrence of Root Rot and Vascular Wilt Diseases in Roselle (Hibiscus sabdariffa L.) in Upper Egypt.

    Science.gov (United States)

    Hassan, Naglaa; Shimizu, Masafumi; Hyakumachi, Mitsuro

    2014-03-01

    Roselle (Hibiscus sabdariffa L.) family Malvaceae is an important crop used in food, cosmetics and pharmaceutics industries. Roselle is cultivated mainly in Upper Egypt (Qena and Aswan governorates) producing 94% of total production. Root rot disease of roselle is one of the most important diseases that attack both seedlings and adult plants causing serious losses in crop productivity and quality. The main objective of the present study is to identify and characterize pathogens associated with root rot and wilt symptoms of roselle in Qena, Upper Egypt and evaluate their pathogenicity under greenhouse and field condition. Fusarium oxysporum, Macrophomina phaseolina, Fusarium solani, Fusarium equiseti and Fusarium semitectum were isolated from the natural root rot diseases in roselle. All isolated fungi were morphologically characterized and varied in their pathogenic potentialities. They could attack roselle plants causing damping-off and root rot/wilt diseases in different pathogenicity tests. The highest pathogenicity was caused by F. oxysporum and M. phaseolina followed by F. solani. The least pathogenic fungi were F. equiseti followed by F. semitectum. It obviously noted that Baladi roselle cultivar was more susceptible to infection with all tested fungi than Sobhia 17 under greenhouse and field conditions. This is the first report of fungal pathogens causing root rot and vascular wilt in roselle in Upper Egypt.

  18. Control of Root Rot and Wilt Diseases of Roselle under Field Conditions

    Science.gov (United States)

    Hassan, Naglaa; Elsharkawy, Mohsen Mohamed; Shimizu, Masafumi

    2014-01-01

    Roselle (Hibiscus sabdariffa L.) is one of the most important medicinal crops in many parts of the world. In this study, the effects of microelements, antioxidants, and bioagents on Fusarium oxysporum, F. solani, and Macrophomina phaseolina, the causal pathogens of root rot and wilt diseases in roselle, were examined under field conditions. Preliminary studies were carried out in vitro in order to select the most effective members to be used in field control trials. Our results showed that microelements (copper and manganese), antioxidants (salicylic acid, ascorbic acid, and EDTA), a fungicide (Dithane M45) and biological control agents (Trichoderma harzianum and Bacillus subtilis) were significantly reduced the linear growth of the causal pathogens. Additionally, application of the previous microelements, antioxidants, a fungicide and biological control agents significantly reduced disease incidence of root rot and wilt diseases under field conditions. Copper, salicylic acid, and T. harzianum showed the best results in this respect. In conclusion, microelements, antioxidants, and biocontrol agents could be used as alternative strategies to fungicides for controlling root rot and wilt diseases in roselle. PMID:25606010

  19. APPLICATIONS OF POTASSIUM FERTILIZER AND Bacillus sp. BIOPESTICIDE FOR INCREASING TOMATO RESISTANCE TO BACTERIAL WILT DISEASE

    Directory of Open Access Journals (Sweden)

    Nur Prihatiningsih

    2011-02-01

    Full Text Available Bacterial wilt on tomato caused by Ralstonia solanacearum is a crucial disease, because it can reduce yield until 50%. The aims of this research were: 1 to find out biopesticide formula for Bacillus sp.growth, 2 to test Bacillus sp. against R. solanacearum in vitro, 3 to test potassium fertilizer combined with Bacillus sp. for enhancing tomato resistance to the bacterial wilt disease. The research was conducted in 2 steps i.e to test the persistence of Bacillus sp. in biopesticide formula, and to test the best combination of both potassium and the Bacillus sp. biopesticide. The results showed that Bacillus B298 was the best isolate in its persistence on the biopesticide formula of organic growth medium+CaCO3+CMC 1%+mannitol 1%, and in inhibiting R. solanacearum. The best biopesticide formula for the Bacillus sp. persistence was growth organic media+ CaCO3+CMC 1%+mannitol 1%. Bacillus sp. was able to increase tomato resistance to the bacterial wilt disease from the category of susceptible to be tolerant and becoming resistant.

  20. Susceptibility to Laurel Wilt and disease incidence in two rare plant species, Pondberry and Pondspice Plant Disease.

    Science.gov (United States)

    Stephen Fraedrich; T Harrington; C Bates; J Johnson; L. Reid; Glenda Susan Best; T Leininger; Tracy Hawkins

    2011-01-01

    Laurel wilt, caused by Raffaelea lauricola, has been responsible for extensive losses of redbay (Persea borbonia) in South Carolina and Georgia since 2003. Symptoms of the disease have been noted in other species of the Lauraceae such as the federally endangered pondberry (Lindera melissifolia) and the threatened pondspice (Litsea aestivalis). Pondberry and pondspice...

  1. Biocontrol potential of Trichoderma harzianum in controlling wilt disease of pistachio caused by Verticillium dahliae

    Directory of Open Access Journals (Sweden)

    Fotoohiyan Zeinab

    2017-06-01

    Full Text Available Verticillium wilt caused by Verticillium dahliae, is one of the most devastating diseases in pistachio orchards in the world including Iran. In search for an effective non-chemical strategy for the management of this disease, we evaluated the biocontrol potential of Trichoderma harzianum isolates obtained from the rhizosphere of healthy pistachio trees in different locations of the Kerman province of Iran against V. dahliae under laboratory and greenhouse conditions. Dual culture tests in the laboratory were conducted in a completely randomized design using 72 T. harzianum isolates. Twenty isolates showed the highest in vitro antagonistic activity. The results indicated that all 20 isolates were capable of inhibiting the mycelial growth of V. dahliae significantly. Among them, isolates Tr8 and Tr19 were the most effective by 88.89% and 85.12% inhibition, respectively. Extracted cell free metabolites of all effective isolates also inhibited the growth of V. dahliae in the culture medium significantly. According to the results, isolates Tr4 and Tr6 inhibited fungal pathogen growth by 94.94% and 88.15% respectively, through production of non-volatile metabolites. In the evaluation of volatile metabolites, isolates Tr5 and Tr4 were the most effective by 26.27% and 24.49% growth inhibition, respectively. Based on the results of the in vitro experiments, the five most effective isolates were selected for evaluation under greenhouse conditions for their biocontrol potential in controlling Verticillium wilt of pistachio. Results of the greenhouse, (in vivo experiments were positive and indicated that the occurrence of wilt disease in plants treated with the antagonists alone or in combination with pathogenic fungus was lower than in plants inoculated with pathogen alone. The overall results of this study suggest that Trichoderma fungal antagonist may be an effective biocontrol agent for the control of Verticillium wilt of pistachio.

  2. Disease control effect of strevertenes produced by Streptomyces psammoticus against tomato fusarium wilt.

    Science.gov (United States)

    Kim, Jeong Do; Han, Jae Woo; Lee, Sung Chul; Lee, Dongho; Hwang, In Cheon; Kim, Beom Seok

    2011-03-09

    During screening of microorganisms producing antifungal metabolites, Streptomyces psammoticus strain KP1404 was isolated. The culture extract of this strain showed potent disease control efficacy against Fusarium wilt on tomato plants. The antifungal metabolites ST-1 and ST-2 were isolated from the culture extract using a variety of chromatographic procedures. On the basis of MS and NMR spectrometric analysis, the structures of the antifungal active compounds ST-1 and ST-2 were determined to be the polyene antibiotics strevertene A and strevertene B, respectively. In vitro, strevertenes A and B showed inhibitory effects against the mycelial growth of Alternaria mali , Aspergillus oryzae , Cylindrocarpon destructans , Colletotrichum orbiculare , Fusarium oxysporum f.sp. lycopersici, and Sclerotinia sclerotiorum , even at concentrations of 4-16 μg/mL. Fusarium wilt development on tomato plants was strongly retarded by treatment with 1 μg/mL of these strevertenes. The disease control efficacies of strevertenes on Fusarium wilt were as remarkable as that of benomyl.

  3. Water Extract from Spent Mushroom Substrate of Hericium erinaceus Suppresses Bacterial Wilt Disease of Tomato

    Science.gov (United States)

    Kwak, A Min; Min, Kyeong Jin; Lee, Sang Yeop

    2015-01-01

    Culture filtrates of six different edible mushroom species were screened for antimicrobial activity against tomato wilt bacteria Ralstonia solanacearum B3. Hericium erinaceus, Lentinula edodes (Sanjo 701), Grifola frondosa, and Hypsizygus marmoreus showed antibacterial activity against the bacteria. Water, n-butanol, and ethyl acetate extracts of spent mushroom substrate (SMS) of H. erinaceus exhibited high antibacterial activity against different phytopathogenic bacteria: Pectobacterium carotovorum subsp. carotovorum, Agrobacterium tumefaciens, R. solanacearum, Xanthomonas oryzae pv. oryzae, X. campestris pv. campestris, X. axonopodis pv. vesicatoria, X. axonopodis pv. citiri, and X. axonopodis pv. glycine. Quantitative real-time PCR revealed that water extracts of SMS (WESMS) of H. erinaceus induced expressions of plant defense genes encoding β-1,3-glucanase (GluA) and pathogenesis-related protein-1a (PR-1a), associated with systemic acquired resistance. Furthermore, WESMS also suppressed tomato wilt disease caused by R. solanacearum by 85% in seedlings and promoted growth (height, leaf number, and fresh weight of the root and shoot) of tomato plants. These findings suggest the WESMS of H. erinaceus has the potential to suppress bacterial wilt disease of tomato through multiple effects including antibacterial activity, plant growth promotion, and defense gene induction. PMID:26539048

  4. The Use of Antioxidants to Control Root Rot and Wilt Diseases of Pepper

    Directory of Open Access Journals (Sweden)

    Montaser Fawzy ABDEL-MONAIM

    2010-06-01

    Full Text Available Ten isolates of Fusarium spp were isolated from pepper plants collected from different locations in New Valley Governorate, Egypt. Fusarium solani isolate FP2 and F. oxysporum isolate FP4 were highly pathogenic isolates but the other isolates moderate or less pathogenic to pepper plants (cv. Anaheim-M. The four antioxidant compounds (coumaric acid, citric acid, propylgalate and salicylic acid each at 100 and 200 ppm were evaluated for their in vitro and in vivo agonist to Fusarium pathogenic isolates caused root rot and wilt diseases in pepper plants. All tested antioxidant compounds reduced damping-off, root rot/wilt and area under root rot/wilt progress curve when used as seed soaking, seedling soaking, and soil drench especially at 200 ppm under greenhouse and field conditions compared with untreated plants. All chemicals increased fresh and dry weight of seedling grown in soil drenching or seed treatment with any antioxidants. At the same time, all tested chemicals significantly increase plant growth parameters i.e plant length, plant branching, and total yield per plant in case of seedling soaking or soil drench. In general, propylgalate at 200 ppm was more efficient in reducing infection with damping-off, root rot and wilt diseases as well as increasing the seedling fresh weight, dry weight, plant length, plant branching, number of pod plant-1 and pod yield plant-1. On the other hand, all tested antioxidants had less or no effect on mycelial dry weight and mycelial leaner growth. On the contrary, all chemicals much reduced spore formation in both Fusarium species at 100 or 200 ppm and the inhibitory effect of antioxidants increased with increasing their concentrations.

  5. Probing behavior of Dysmicoccus brevipes mealybug in pineapple plants

    Directory of Open Access Journals (Sweden)

    Lenira Viana Costa Santa-Cecília

    2016-12-01

    Full Text Available Differences in susceptibility to viruses in plants may be partially explained by the insect vector probing behavior and by the presence of phenolic compounds, which are often associated with defense strategies. This study aimed at detecting barriers that may difficult the probing activity of the Dysmicoccus brevipes (Pseudococcidae pineapple mealybug, a vector of the pineapple mealybug wilt-associated virus, as well as evaluating the phenolic content of plants, in order to verify any possible relationship with the probing behavior, by using the electrical penetration graphs (EPG technique. Seedlings of 'Smooth Cayenne' and 'Pérola' pineapple cultivars were used in the experiments. Only 28 % and 21 % of the mealybugs reached the phloem of the 'Smooth Cayenne' and 'Pérola' cultivars, respectively, over 16 h of recording, with an average of 9 h to reach the phloem vessels. The xylem phase was extended in both cultivars and represented approximately 31 % ('Smooth Cayenne' and 44 % ('Pérola' of the recording time. The phenolic contents of both cultivars were similar.

  6. Resistance screening trials on coconut varieties to Cape Saint Paul Wilt Disease in Ghana

    Directory of Open Access Journals (Sweden)

    Quaicoe Robert Nketsia

    2009-03-01

    Full Text Available The Cape Saint Paul Wilt Disease (CSPWD is a coconut lethal yellowing type disease (LY and is the single most serious threat to coconut cultivation in Ghana. The recommended disease management strategy is the cultivation of disease-resistant coconut varieties. More than 38 varieties have been screened for their resistance to CSPWD since 1956 and the results are reviewed in this paper. Two varieties, Sri Lanka Green Dwarf (SGD and Vanuatu Tall (VTT, have shown high resistance to the disease, and their hybrid (SGD × VTT is under observation to determine its performance. A programme to rehabilitate the CSPWD-devastated areas was started in 1999. Emerging results indicate that the MYD × VTT hybrid being used for the programme, succumbs to the disease under intense disease pressure. A redirection of the rehabilitation programme and the screening of more varieties are recommended.

  7. A review of coffee wilt disease, Gibberella xylarioides (Fusarium ...

    African Journals Online (AJOL)

    Coffee is vital to the economy of East and Central Africa, providing a major source of foreign exchange earnings and as a cash crop, supporting the livelihood of millions of people who are involved in cultivation, processing, marketing, and export. Coffee is attacked by various disease-causing organisms such as fungi, ...

  8. Chapter 11 - Progression of Laurel Wilt Disease in Georgia: 2009–11 (Project SC-EM-08-02)

    Science.gov (United States)

    R. Scott Cameron; Chip Bates; James Johnson

    2014-01-01

    Laurel wilt disease (LWD) is caused by the fungus Raffaelea lauricola and vectored by the redbay ambrosia beetle (RAB), Xyleborus glabratus (Fraedrich and others 2008). The pathogen and vector were apparently introduced from Asia through the Port of Savannah, and the disease has spread rapidly throughout the lower coastal plains forests in Georgia, killing nearly all...

  9. Selection and Characterization of Endophytic Bacteria as Biocontrol Agents of Tomato Bacterial Wilt Disease

    Directory of Open Access Journals (Sweden)

    ABDJAD ASIH NAWANGSIH

    2011-06-01

    Full Text Available Biological control of bacterial wilt pathogen (Ralstonia solanacearum of tomato using endophytic bacteria is one of the alternative control methods to support sustainable agriculture. This study was conducted to select and characterize endophytic bacteria isolated from healthy tomato stems and to test their ability to promote plant growth and suppress bacterial wilt disease. Among 49 isolates successfully isolated, 41 were non-plant pathogenic. Green house test on six selected isolates based on antagonistic effect on R. solanacearum or ability to suppress R. solanacearum population in dual culture assays obtained BC4 and BL10 isolates as promising biocontrol agents. At six weeks after transplanting, plants treated with BC4 isolate showed significantly lower disease incidence (33% than that of control (83%. Plants height was not significantly affected by endophytic bacterial treatments. Based on 16S rRNA sequence, BC4 isolate had 97% similarity with Staphylococcus epidermidis (accession number EU834240.1, while isolate BL10 had 98% similarity with Bacillus amyloliquefaciens strain JK-SD002 (accession number AB547229.1.

  10. An Integrated Insight into the Relationship between Soil Microbial Community and Tobacco Bacterial Wilt Disease

    Science.gov (United States)

    Yang, Hongwu; Li, Juan; Xiao, Yunhua; Gu, Yabing; Liu, Hongwei; Liang, Yili; Liu, Xueduan; Hu, Jin; Meng, Delong; Yin, Huaqun

    2017-01-01

    The soil microbial communities play an important role in plant health, however, the relationship between the below-ground microbiome and above-ground plant health remains unclear. To reveal such a relationship, we analyzed soil microbial communities through sequencing of 16S rRNA gene amplicons from 15 different tobacco fields with different levels of wilt disease in the central south part of China. We found that plant health was related to the soil microbial diversity as plants may benefit from the diverse microbial communities. Also, those 15 fields were grouped into ‘healthy’ and ‘infected’ samples based upon soil microbial community composition analyses such as unweighted paired-group method with arithmetic means (UPGMA) and principle component analysis, and furthermore, molecular ecological network analysis indicated that some potential plant-beneficial microbial groups, e.g., Bacillus and Actinobacteria could act as network key taxa, thus reducing the chance of plant soil-borne pathogen invasion. In addition, we propose that a more complex soil ecology network may help suppress tobacco wilt, which was also consistent with highly diversity and composition with plant-beneficial microbial groups. This study provides new insights into our understanding the relationship between the soil microbiome and plant health. PMID:29163453

  11. Detection and management of Xyleborus glabratus and other vectors of laurel wilt, a lethal disease affecting avocados in Florida

    Science.gov (United States)

    The redabay ambrosia beetle, Xyleborus glabratus, carries a phytopathogenic symbiont, Raffaelea lauricola, which causes laurel wilt, a lethal vascular disease of some Lauraceae species. Both X. glabratus and R. lauricola are natives of Asia that recently invaded much of the coastal plain of the sout...

  12. Search for alternate hosts of the coconut Cape Saint Paul Wilt Disease pathogen

    Directory of Open Access Journals (Sweden)

    Yankey Egya Ndede

    2009-03-01

    Full Text Available Lethal Yellowing disease locally called Cape Saint Paul wilt disease (CSPWD is the bane of the coconut industry in Ghana and is caused by a phytoplasma. In Ghana, there are areas where the disease has re-infected re-plantings long after decimating all the palms in the area. This brings to the fore the possibility of alternate hosts in the spread of the disease because the pathogen is an obligate parasite. In this work, a number of plants were screened for their host status to the CSPWD pathogen. The presence of phytoplasmas in these plants was tested by polymerase chain reaction analysis using universal phytoplasma primers P1/P7 and CSPWD-specific primers G813/GAKSR. Although Desmodium adscendens tested positive to the CSPWD-specific primers, cloning and sequencing did not confirm it as an alternate host. The identification of alternate hosts will help us to evolve sound control strategies against the spread of the disease.

  13. Significant relationship between soil bacterial community structure and incidence of bacterial wilt disease under continuous cropping system.

    Science.gov (United States)

    She, Siyuan; Niu, Jiaojiao; Zhang, Chao; Xiao, Yunhua; Chen, Wu; Dai, Linjian; Liu, Xueduan; Yin, Huaqun

    2017-03-01

    Soil bacteria are very important in biogeochemical cycles and play significant role in soil-borne disease suppression. Although continuous cropping is responsible for soil-borne disease enrichment, its effect on tobacco plant health and how soil bacterial communities change are yet to be elucidated. In this study, soil bacterial communities across tobacco continuous cropping time-series fields were investigated through high-throughput sequencing of 16S ribosomal RNA genes. The results showed that long-term continuous cropping could significantly alter soil microbial communities. Bacterial diversity indices and evenness indices decreased over the monoculture span and obvious variations for community structures across the three time-scale tobacco fields were detected. Compared with the first year, the abundances of Arthrobacter and Lysobacter showed a significant decrease. Besides, the abundance of the pathogen Ralstonia spp. accumulated over the monoculture span and was significantly correlated with tobacco bacterial wilt disease rate. Moreover, Pearson's correlation demonstrated that the abundance of Arthrobacter and Lysobacter, which are considered to be beneficial bacteria had significant negative correlation with tobacco bacterial wilt disease. Therefore, after long-term continuous cropping, tobacco bacterial wilt disease could be ascribed to the alteration of the composition as well as the structure of the soil microbial community.

  14. Cotton Wilt and the Environment

    Indian Academy of Sciences (India)

    as well as mature healthy plants growing in diseased soil. (2) Fusarium hyphae may not be present in the wilt-affected plants. (3) Superphosphate ... agencies, such as organic manure, aluminium salts, lime and water-logging. (8) Seedlings in the very first stages of wilt-infection, if transplanted into healthy soil, develop into ...

  15. Stability Analysis and Optimal Control Strategy for Prevention of Pine Wilt Disease

    Directory of Open Access Journals (Sweden)

    Kwang Sung Lee

    2014-01-01

    Full Text Available We propose a mathematical model of pine wilt disease (PWD which is caused by pine sawyer beetles carrying the pinewood nematode (PWN. We calculate the basic reproduction number R0 and investigate the stability of a disease-free and endemic equilibrium in a given mathematical model. We show that the stability of the equilibrium in the proposed model can be controlled through the basic reproduction number R0. We then discuss effective optimal control strategies for the proposed PWD mathematical model. We demonstrate the existence of a control problem, and then we apply both analytical and numerical techniques to demonstrate effective control methods to prevent the transmission of the PWD. In order to do this, we apply two control strategies: tree-injection of nematicide and the eradication of adult beetles through aerial pesticide spraying. Optimal prevention strategies can be determined by solving the corresponding optimality system. Numerical simulations of the optimal control problem using a set of reasonable parameter values suggest that reducing the number of pine sawyer beetles is more effective than the tree-injection strategy for controlling the spread of PWD.

  16. Seedling regeneration on decayed pine logs after the deforestation events caused by pine wilt disease

    Directory of Open Access Journals (Sweden)

    Y. Fukasawa

    2016-12-01

    Full Text Available Coarse woody debris (CWD forms an important habitat suitable for tree seedling establishment, and the CWD decay process influences tree seedling community. In Japan, a severe dieback of Pinus densiflora Sieb. & Zucc. caused by pine wilt disease (PWD damaged huge areas of pine stands but creates huge mass of pine CWD. It is important to know the factors influencing seedling colonization on pine CWD and their variations among geographical gradient in Japan to expect forest regeneration in post-PWD stands. I conducted field surveys on the effects of latitude, climates, light condition, decay type of pine logs, and log diameter on tree seedling colonization at ten geographically distinct sites in Japan. In total, 59 tree taxa were recorded as seedlings on pine logs. Among them, 13 species were recorded from more than five sites as adult trees or seedlings and were used for the analyses. A generalized linear model showed that seedling colonization of Pinus densiflora was negatively associated with brown rot in sapwood, while that of Rhus trichocarpa was positively associated with brown rot in heartwood. Regeneration of Ilex macropoda had no relationships with wood decay type but negatively associated with latitude and MAT, while positively with log diameter. These results suggested that wood decay type is a strong determinant of seedling establishment for certain tree species, even at a wide geographical scale; however, the effect is tree species specific.

  17. Towards allele mining of bacterial wilt disease resistance gene in tomato

    International Nuclear Information System (INIS)

    Galvez, H.F.; Narciso, J.O.; Opina, N.L.; Canama, A.O.; Colle, M.G.; Latiza, M.A.; Caspillo, C.L.; Bituin, J.L.; Frankie, R.B.; Hautea, D.M.

    2005-01-01

    Tomato (Lycopersicon esculentum Mill.) is the most important vegetable commodity of the Philippines. Bacterial wilt caused by Ralstonia solanacearum is one serious constraint in tomato production particularly during off-season planting. A major locus derived from H7996 that confers resistance to bacterial wilt has been mapped in the tomato genome. To validate the biological function of the resistance locus and generate multiple allele -mimics-, targeted mutation was induced in tomato using gamma ray and ethyl methane sulfonate (EMS) mutagens. Suitable mutagen treatment was established by evaluating a wide range of mutagen doses/concentrations for a) percent seed germination, b) reduction in plant height, and c) loss of resistance. Six hundred Gy and 1.0% EMS were identified to generate large M1 families of H7996. From 10,000 initial seeds treated with either gamma ray or EMS, a total of 3,663 M1 plants were generated. M2 seeds were harvested from all surviving M1 plants. Several DNA markers have been resourced and are being developed specific to the bacterial wilt resistant gene. In the large M2 population, of H7996, both the phenotypic manifestation of bacterial wilt susceptibility and nucleotide changes in the resistance locus will be evaluated. Large M3 families for the different allele series of the bacterial wilt resistance gene will be established for future high throughput TILLING (Targeting Induced Local Lesions in Genomes) analysis in the gene region

  18. Genome and Transcriptome Analysis of the Fungal Pathogen Fusarium oxysporum f. sp. cubense Causing Banana Vascular Wilt Disease

    Science.gov (United States)

    Zeng, Huicai; Fan, Dingding; Zhu, Yabin; Feng, Yue; Wang, Guofen; Peng, Chunfang; Jiang, Xuanting; Zhou, Dajie; Ni, Peixiang; Liang, Changcong; Liu, Lei; Wang, Jun; Mao, Chao

    2014-01-01

    Background The asexual fungus Fusarium oxysporum f. sp. cubense (Foc) causing vascular wilt disease is one of the most devastating pathogens of banana (Musa spp.). To understand the molecular underpinning of pathogenicity in Foc, the genomes and transcriptomes of two Foc isolates were sequenced. Methodology/Principal Findings Genome analysis revealed that the genome structures of race 1 and race 4 isolates were highly syntenic with those of F. oxysporum f. sp. lycopersici strain Fol4287. A large number of putative virulence associated genes were identified in both Foc genomes, including genes putatively involved in root attachment, cell degradation, detoxification of toxin, transport, secondary metabolites biosynthesis and signal transductions. Importantly, relative to the Foc race 1 isolate (Foc1), the Foc race 4 isolate (Foc4) has evolved with some expanded gene families of transporters and transcription factors for transport of toxins and nutrients that may facilitate its ability to adapt to host environments and contribute to pathogenicity to banana. Transcriptome analysis disclosed a significant difference in transcriptional responses between Foc1 and Foc4 at 48 h post inoculation to the banana ‘Brazil’ in comparison with the vegetative growth stage. Of particular note, more virulence-associated genes were up regulated in Foc4 than in Foc1. Several signaling pathways like the mitogen-activated protein kinase Fmk1 mediated invasion growth pathway, the FGA1-mediated G protein signaling pathway and a pathogenicity associated two-component system were activated in Foc4 rather than in Foc1. Together, these differences in gene content and transcription response between Foc1 and Foc4 might account for variation in their virulence during infection of the banana variety ‘Brazil’. Conclusions/Significance Foc genome sequences will facilitate us to identify pathogenicity mechanism involved in the banana vascular wilt disease development. These will thus advance

  19. Potential distribution of pine wilt disease under future climate change scenarios.

    Directory of Open Access Journals (Sweden)

    Akiko Hirata

    Full Text Available Pine wilt disease (PWD constitutes a serious threat to pine forests. Since development depends on temperature and drought, there is a concern that future climate change could lead to the spread of PWD infections. We evaluated the risk of PWD in 21 susceptible Pinus species on a global scale. The MB index, which represents the sum of the difference between the mean monthly temperature and 15 when the mean monthly temperatures exceeds 15°C, was used to determine current and future regions vulnerable to PWD (MB ≥ 22. For future climate conditions, we compared the difference in PWD risks among four different representative concentration pathways (RCPs 2.6, 4.5, 6.0, and 8.5 and two time periods (2050s and 2070s. We also evaluated the impact of climate change on habitat suitability for each Pinus species using species distribution models. The findings were then integrated and the potential risk of PWD spread under climate change was discussed. Within the natural Pinus distribution area, southern parts of North America, Europe, and Asia were categorized as vulnerable regions (MB ≥ 22; 16% of the total Pinus distribution area. Representative provinces in which PWD has been reported at least once overlapped with the vulnerable regions. All RCP scenarios showed expansion of vulnerable regions in northern parts of Europe, Asia, and North America under future climate conditions. By the 2070s, under RCP 8.5, an estimated increase in the area of vulnerable regions to approximately 50% of the total Pinus distribution area was revealed. In addition, the habitat conditions of a large portion of the Pinus distribution areas in Europe and Asia were deemed unsuitable by the 2070s under RCP 8.5. Approximately 40% of these regions overlapped with regions deemed vulnerable to PWD, suggesting that Pinus forests in these areas are at risk of serious damage due to habitat shifts and spread of PWD.

  20. Induced resistance by cresotic acid (3-hydroxy-4-methyl methylbenzoic acid) against wilt disease of melon and cotton

    International Nuclear Information System (INIS)

    Dong, H.; Li, Z.; Zhang, D.; Li, W.; Tang, W.

    2004-01-01

    Cresotic acid (3-hydroxy-4-methylbenzoic acid) was proved be active in controlling wilt diseases of melon and cotton plants grown in the house. Soil drench with 200-1000 ppm cresotic acid induced 62-77 %, 69-79 % and 50-60 % protection against Fusarium oxysporum f.sp melonis (FOM) in melon, Fusarium oxysporum f.sp vasinfectum (FOV) and Verticillium dahliae in cotton, respectively. Since no inhibitory effect of cresotic acid on mycelial growth of these three fungual pathogens was observed in vitro, it is suggested that control of these wilt diseases with cresotic acid resulted from induced resistance. Cresotic acid induced resistance in melon plants not only against race 0, race 1, race 2 and race 1,2, but also against a mixture of these four races of FOM, suggesting a non-race- specific resistance. Level of induced resistance by cresotic acid against FOM depended on inoculum pressure applied to melon plants. At 25 day after inoculation with FOM, percentage protection induced by cresotic acid under low inoculum pressure retained a level of 51 %, while under high inoculum pressure percentage protection decreased to only 10 %. High concentrations of cresotic acid significantly reduced plant growth. Reduction in fresh weight of melon (36-51%) and cotton (42-71%) was obtained with 500-1000 ppm cresotic acid, while only less than 8% reduction occurred with 100-200 ppm. (author)

  1. Disease interactions in a shared host plant: effects of pre-existing viral infection on cucurbit plant defense responses and resistance to bacterial wilt disease.

    Directory of Open Access Journals (Sweden)

    Lori R Shapiro

    Full Text Available Both biotic and abiotic stressors can elicit broad-spectrum plant resistance against subsequent pathogen challenges. However, we currently have little understanding of how such effects influence broader aspects of disease ecology and epidemiology in natural environments where plants interact with multiple antagonists simultaneously. In previous work, we have shown that healthy wild gourd plants (Cucurbita pepo ssp. texana contract a fatal bacterial wilt infection (caused by Erwinia tracheiphila at significantly higher rates than plants infected with Zucchini yellow mosaic virus (ZYMV. We recently reported evidence that this pattern is explained, at least in part, by reduced visitation of ZYMV-infected plants by the cucumber beetle vectors of E. tracheiphila. Here we examine whether ZYMV-infection may also directly elicit plant resistance to subsequent E. tracheiphila infection. In laboratory studies, we assayed the induction of key phytohormones (SA and JA in single and mixed infections of these pathogens, as well as in response to the feeding of A. vittatum cucumber beetles on healthy and infected plants. We also tracked the incidence and progression of wilt disease symptoms in plants with prior ZYMV infections. Our results indicate that ZYMV-infection slightly delays the progression of wilt symptoms, but does not significantly reduce E. tracheiphila infection success. This observation supports the hypothesis that reduced rates of wilt disease in ZYMV-infected plants reflect reduced visitation by beetle vectors. We also documented consistently strong SA responses to ZYMV infection, but limited responses to E. tracheiphila in the absence of ZYMV, suggesting that the latter pathogen may effectively evade or suppress plant defenses, although we observed no evidence of antagonistic cross-talk between SA and JA signaling pathways. We did, however, document effects of E. tracheiphila on induced responses to herbivory that may influence host

  2. Entomopathogenic fungi as a biological control agents for the vector of the laurel wilt disease, the redbay ambrosia beetle, Xyleborus glabratus (Coleoptera: Curculionidae)

    Science.gov (United States)

    The redbay ambrosia beetle (RAB), Xyleborus glabratus (Coleoptera: Curculionidae: Scolytinae) vectors the fungal pathogen, Raffaelea lauricola, which causes laurel wilt (LW), a lethal disease of trees in the family Lauraceae, including the most commercially important crop in this family, avocado, Pe...

  3. Determination of Tolerance Levels of Cotton Genotypes Obtained from F6-F7 Generation against Verticillium Wilt Disease Caused by Verticillium dahliae Kleb.

    OpenAIRE

    Oktay EROĞAN; Emine KARADEMIR; Çetin KARADEMIR; Aydın UNAY

    2013-01-01

    The susceptibility of cotton genotypes obtained from F6 and F7 generations to Verticillium wilt (VW) disease (Verticillium dahliae Kleb.), was studied under artificial and natural infestation during 2009 and 2010 growing seasons at the Cotton Research Institute’s, Nazilli, Aydın, Turkey. In this study, fifteen cotton breeding lines and two control varieties were used as plant material. During the cotton growing season, foliar disease index (FDI), vascular disease index (VDI) and pot disease i...

  4. Paternal inheritance in mealybugs (Hemiptera: Coccoidea: Pseudococcidae)

    Science.gov (United States)

    Kol-Maimon, Hofit; Mendel, Zvi; Franco, José Carlos; Ghanim, Murad

    2014-10-01

    Mealybugs have a haplodiploid reproduction system, with paternal genome elimination (PGE); the males are diploid soon after fertilization, but during embryogenesis, the male paternal set of chromosomes becomes heterochromatic (HC) and therefore inactive. Previous studies have suggested that paternal genes can be passed on from mealybug males to their sons, but not necessarily by any son, to the next generation. We employed crosses between two mealybug species— Planococcus ficus (Signoret) and Planococcus citri (Risso)—and between two populations of P. ficus, which differ in their mode of pheromone attraction, in order to demonstrate paternal inheritance from males to F2 through F1 male hybrids. Two traits were monitored through three generations: mode of male pheromone attraction (pherotype) and sequences of the internal transcribed spacer 2 (ITS2) gene segment (genotype). Our results demonstrate that paternal inheritance in mealybugs can occur from males to their F2 offspring, through F1 males (paternal line). F2 backcrossed hybrid males expressed paternal pherotypes and ITS2 genotypes although their mother originated through a maternal population. Further results revealed other, hitherto unknown, aspects of inheritance in mealybugs, such as that hybridization between the two species caused absence of paternal traits in F2 hybrid females produced by F1 hybrid females. Furthermore, hybridization between the two species raised the question of whether unattracted males have any role in the interactions between P. ficus and P. citri.

  5. High-resolution melt and morphological analyses of mealybugs (Hemiptera: Pseudococcidae) from cacao: tools for the control of Cacao swollen shoot virus spread.

    Science.gov (United States)

    Wetten, Andy; Campbell, Colin; Allainguillaume, Joël

    2016-03-01

    Mealybugs (Hemiptera: Coccoidea: Pseudococcidae) are key vectors of badnaviruses, including Cacao swollen shoot virus (CSSV), the most damaging virus affecting cacao (Theobroma cacao L.). The effectiveness of mealybugs as virus vectors is species dependent, and it is therefore vital that CSSV resistance breeding programmes in cacao incorporate accurate mealybug identification. In this work, the efficacy of a CO1-based DNA barcoding approach to species identification was evaluated by screening a range of mealybugs collected from cacao in seven countries. Morphologically similar adult females were characterised by scanning electron microscopy, and then, following DNA extraction, were screened with CO1 barcoding markers. A high degree of CO1 sequence homology was observed for all 11 individual haplotypes, including those accessions from distinct geographical regions. This has allowed the design of a high-resolution melt (HRM) assay capable of rapid identification of the commonly encountered mealybug pests of cacao. HRM analysis readily differentiated between mealybug pests of cacao that cannot necessarily be identified by conventional morphological analysis. This new approach, therefore, has potential to facilitate breeding for resistance to CSSV and other mealybug-transmitted diseases. © 2015 Society of Chemical Industry.

  6. Disease epidemiology and genetic diversity of fusarium oxysporum f. sp. elaeidis, cause of fusarium wilt of oil palm (Elaeis guineensis Jacq.)

    OpenAIRE

    Hefni Rusli, M.; Wheals, Alan E.; Sharma, Sweta; Seman, Idris A.; Cooper, Richard M.

    2017-01-01

    Vascular wilt disease caused by Fusarium oxysporum f. sp. elaeidis (Foe) has devasted oil palm in west and central Africa. This study investigates the spatial distribution of Foe, whereby non-random, clustered patterns of the disease were recorded in four separate plantations in Ghana; infection from tree to tree via elongating roots therefore plays a more significant role than aerial distribution by conidiospores, with management implications. Control of Foe with disease-resistant palm lines...

  7. Biological control of wilt disease complex on tomato crop caused by Meloidogyne javanica and Fusarium oxysporum f.sp. lycopersici by Verticillium leptobactrum.

    Science.gov (United States)

    Hajji-Hedfi, Lobna; Regaieg, Hajer; Larayedh, Asma; Chihani, Noura; Horrigue-Raouani, Najet

    2017-09-23

    The efficacy of Verticillium leptobactrum isolate (HR1) was evaluated in the control of root-knot nematode and Fusarium wilt fungus under laboratory and greenhouse conditions. Five concentrations of V. leptobactrum (HR1) isolate were tested for their nematicidal and fungicidal activities against Meloidogyne javanica and Fusarium oxysporum f.sp. lycopersici in vitro. Laboratory trials showed that mycelium growth inhibition of Fusarium wilt fungus was correlated to the increase of the concentration of culture filtrate. All dilutions showed efficiency in reducing the growth of Fusarium oxysporum f.sp. lycopersici. The greatest nematicidal activity was observed at 50, 75, and 100% filtrate dilutions. The egg hatching percentage reached 42%, and the juvenile's corrected mortality registered 90% for the above treatments. In greenhouse experiment, the biocontrol agent fungus enhanced significantly tomato growth components (height and weight of plant and root). The multiplication rate of root-knot nematode and the Fusarium wilt disease incidence declined significantly with soil application of V. leptobactrum as with chemical treatments. The isolate HR1 was efficient to control wilt disease complex caused by M. javanica and Fusarium oxysporum f.sp. lycopersici.

  8. Potato Bacterial Wilt Management in the Central Highlands of ...

    African Journals Online (AJOL)

    management measures of potato wilt, late blight and viruses. The result ... symptom less carriers of the pathogen (Rueda,. 1990 .... diffuse light store (DLS) based on cost sharing. Bacterial wilt ..... nitrogen from the air which increases the availability of the element to the plant and ..... Bacterial wilt disease in Asia and South.

  9. Spatial Distribution of Coffee Wilt Disease Under Roguing and Replanting Conditions: A Case Study from Kaweri Estate in Uganda.

    Science.gov (United States)

    Pinard, F; Makune, S E; Campagne, P; Mwangi, J

    2016-11-01

    Based on time and spatial dynamic considerations, this study evaluates the potential role of short- and long-distance dispersal in the spread of coffee wilt disease (CWD) in a large commercial Robusta coffee estate in Uganda (Kaweri, 1,755 ha) over a 4-year period (2008 to 2012). In monthly surveys, total disease incidence, expansion of infection foci, and the occurrence of isolated infected trees were recorded and submitted to spatial analysis. Incidence was higher and disease progression faster in old coffee plantings compared with young plantings, indicating a lack of efficiency of roguing for reducing disease development in old plantings. At large spatial scale (approximately 1 km), Moran indices (both global and local) revealed the existence of clusters characterized by contrasting disease incidences. This suggested that local environmental conditions were heterogeneous or there were spatial interactions among blocks. At finer spatial scale (approximately 200 m), O-ring statistics revealed positive correlation between distant infection sites across distances as great as 60 m. Although these observations indicate the role of short-distance dispersal in foci expansion, dispersal at greater distances (>20 m) appeared to also contribute to both initiation of new foci and disease progression at coarser spatial scales. Therefore, our results suggested the role of aerial dispersal in CWD progression.

  10. Dynamics of Colonization and Expression of Pathogenicity Related Genes in Fusarium oxysporum f.sp. ciceri during Chickpea Vascular Wilt Disease Progression.

    Directory of Open Access Journals (Sweden)

    Medha L Upasani

    Full Text Available Fusarium wilt caused by Fusarium oxysporum f.sp. ciceri (Foc is a constant threat to chickpea productivity in several parts of the world. Understanding the molecular basis of chickpea-Foc interaction is necessary to improve chickpea resistance to Foc and thereby the productivity of chickpea. We transformed Foc race 2 using green fluorescent protein (GFP gene and used it to characterize pathogen progression and colonization in wilt-susceptible (JG62 and wilt-resistant (Digvijay chickpea cultivars using confocal microscopy. We also employed quantitative PCR (qPCR to estimate the pathogen load and progression across various tissues of both the chickpea cultivars during the course of the disease. Additionally, the expression of several candidate pathogen virulence genes was analyzed using quantitative reverse transcriptase PCR (qRT-PCR, which showed their characteristic expression in wilt-susceptible and resistant chickpea cultivars. Our results suggest that the pathogen colonizes the susceptible cultivar defeating its defense; however, albeit its entry in the resistant plant, further proliferation is severely restricted providing an evidence of efficient defense mechanism in the resistant chickpea cultivar.

  11. Development and preventative effect against pine wilt disease of a novel liquid formulation of emamectin benzoate.

    Science.gov (United States)

    Takai, Kazuya; Suzuki, Toshio; Kawazu, Kazuyoshi

    2003-03-01

    Injection of the poorly water-soluble emamectin benzoate (EB) into pine trunks required the development of an efficient liquid formulation. For injection into big trees in forests a good rate of injection and a high active content were required. Tests on the viscosity and EB-solubilizing ability of 14 various solubilizers in diethylene glycol monobutyl ether (DGMBE) led to the selection of Sorpol SM-100PM as the solubilizer of the formulation. Relationships between the solubilizing ability and amounts of Sorpol SM-100PM and DGMBE relative to that of EB, and between the concentration of the latter and the viscosity or the injection rate of the formulation led to a novel 40 g litre(-1) emamectin benzoate formulation (Shot Wan Liquid Formulation), which was composed of EB (40), Sorpol SM-100PM (120), DGMBE (160) and distilled water (50 g litre(-1)) in methanol. Injection of this formulation at a dose of 10 g EB per unit volume of pine tree prevented over 90% of the trees from wilting caused by pine wood nematode, and this preventative effect continued for 3 years. Neither discolouration of the leaves nor injury around the injection hole on the trees was observed after injection of the formulation.

  12. Fungal cell wall polymer based nanoparticles in protection of tomato plants from wilt disease caused by Fusarium oxysporum f.sp. lycopersici.

    Science.gov (United States)

    Sathiyabama, M; Charles, R Einstein

    2015-11-20

    Cell wall polymer (chitosan) was isolated from Fusarium oxysporum f.sp. lycopersici. They were cross linked with sodium tripolyphosphate (TPP) to synthesize nanoparticles (CWP-NP). The nanoparticles were characterized by FTIR, DLS, SEM, XRD and NMR analyses. The isolated CWP-NP exhibit antifungal activity under in vitro condition. The foliar application of the CWP-NP to tomato plants challenged with F. oxysporum f. sp. lycopersici showed delay in wilt disease symptom expression and reduce the wilt disease severity. Treated plants also showed enhanced yield. These results suggested the role of the CWP-NP in protecting tomato plants from F. oxysporum f.sp. lycopersici infection. Copyright © 2015 Elsevier Ltd. All rights reserved.

  13. First report of Xyleborus glabratus (Coleoptera: Curculionidae: Scolytinae) and laurel wilt in Louisiana, USA: The disease continues westward on sassafras

    Science.gov (United States)

    Stephen W. Fraedrich; C. Wood Johnson; Roger D. Menard; Thomas C. Harrington; Rabiu Olatinwo; G. Susan Best

    2015-01-01

    Laurel wilt, caused by Raffaelea lauricola Harrington, Fraedrich & Aghayeva (Ophiostomatales: Ophiostomataceae), has spread rapidly through the coastal plains forests of the southeastern United States (USA) with devastating effects on redbay (Persea borbonia [L.] Spreng.; Laurales: Lauraceae) populations (Fraedrich et...

  14. Diversity of bacteria associated with Bursaphelenchus xylophilus and other nematodes isolated from Pinus pinaster trees with pine wilt disease.

    Directory of Open Access Journals (Sweden)

    Diogo Neves Proença

    Full Text Available The pinewood nematode (PWN, Bursaphelenchus xylophilus, has been thought to be the only causal agent of pine wilt disease (PWD, however, since bacteria have been suggested to play a role in PWD, it is important to know the diversity of the microbial community associated to it. This study aimed to assess the microbial community associated with B. xylophilus and with other nematodes isolated from pine trees, Pinus pinaster, with PWD from three different affected forest areas in Portugal. One hundred and twenty three bacteria strains were isolated from PWN and other nematodes collected from 14 P. pinaster. The bacteria strains were identified by comparative analysis of the 16S rRNA gene partial sequence. All except one gram-positive strain (Actinobacteria belonged to the gram-negative Beta and Gammaproteobacteria. Most isolates belonged to the genus Pseudomonas, Burkholderia and to the family Enterobacteriaceae. Species isolated in higher percentage were Pseudomonas lutea, Yersinia intermedia and Burkholderia tuberum. The major bacterial population associated to the nematodes differed according to the forest area and none of the isolated bacterial species was found in all different forest areas. For each of the sampled areas, 60 to 100% of the isolates produced siderophores and at least 40% produced lipases. The ability to produce siderophores and lipases by most isolates enables these bacteria to have a role in plant physiological response. This research showed a high diversity of the microbial community associated with B. xylophilus and other nematodes isolated from P. pinaster with PWD.

  15. Diversity of bacteria associated with Bursaphelenchus xylophilus and other nematodes isolated from Pinus pinaster trees with pine wilt disease.

    Science.gov (United States)

    Proença, Diogo Neves; Francisco, Romeu; Santos, Clara Vieira; Lopes, André; Fonseca, Luís; Abrantes, Isabel M O; Morais, Paula V

    2010-12-09

    The pinewood nematode (PWN), Bursaphelenchus xylophilus, has been thought to be the only causal agent of pine wilt disease (PWD), however, since bacteria have been suggested to play a role in PWD, it is important to know the diversity of the microbial community associated to it. This study aimed to assess the microbial community associated with B. xylophilus and with other nematodes isolated from pine trees, Pinus pinaster, with PWD from three different affected forest areas in Portugal. One hundred and twenty three bacteria strains were isolated from PWN and other nematodes collected from 14 P. pinaster. The bacteria strains were identified by comparative analysis of the 16S rRNA gene partial sequence. All except one gram-positive strain (Actinobacteria) belonged to the gram-negative Beta and Gammaproteobacteria. Most isolates belonged to the genus Pseudomonas, Burkholderia and to the family Enterobacteriaceae. Species isolated in higher percentage were Pseudomonas lutea, Yersinia intermedia and Burkholderia tuberum. The major bacterial population associated to the nematodes differed according to the forest area and none of the isolated bacterial species was found in all different forest areas. For each of the sampled areas, 60 to 100% of the isolates produced siderophores and at least 40% produced lipases. The ability to produce siderophores and lipases by most isolates enables these bacteria to have a role in plant physiological response. This research showed a high diversity of the microbial community associated with B. xylophilus and other nematodes isolated from P. pinaster with PWD.

  16. Effect of nutrition and environmental factors on the endoparasitic fungus Esteya vermicola, a biocontrol agent against pine wilt disease.

    Science.gov (United States)

    Xue, Jianjie; Zhang, Yongan; Wang, Chunyan; Wang, Yuzhu; Hou, Jingang; Wang, Zhen; Wang, Yunbo; Gu, Lijuan; Sung, Changkeun

    2013-09-01

    The nematophagous fungus Esteya vermicola has tremendous potential for biological control. This species exhibits strong infectious activity against pinewood nematodes, whereas the study on the effect of nutrition and environmental factors is still of paucity. Carbon (C), nitrogen (N), pH value, temperature, and water activity have great impact on the fungal growth, sporulation, and germination. In nutrition study, the greatest number of conidia (2.36 × 10(9) per colony) was obtained at the C:N ratio of 100:1 with a carbon concentration 32 g l(-1). In addition, the germination rate and radial growth of E. vermicola were used to evaluate the effects of environmental conditions and they were optimized as following: pH 5.5, 26 °C and water activity of 0.98. Our results also confirmed that variation of environmental factors has a detrimental influence on the efficacy of active conidia and growth of fungus. Moreover, under above optimal condition, the biocontrol efficacy was significantly improved in regard to the increase of adhesive and mortality rate, which highlight the study on the application of E. vermicola as pine wilt disease biocontrol agent.

  17. DENSITY AND DISTRIBUTION OF ENSET ROOT MEALYBUGS ON ...

    African Journals Online (AJOL)

    Administrator

    insect pest of enset (Ensete ventricosum) in southern Ethiopia. ... An average of 87 adult enset root mealybugs were collected from roots and corms per plant. The ..... (IPM) control options on enset root mealybug population numbers or when screening large numbers of enset clones for their resistance against this insect.

  18. Deep 16S rRNA Pyrosequencing Reveals a Bacterial Community Associated with Banana Fusarium Wilt Disease Suppression Induced by Bio-Organic Fertilizer Application

    Science.gov (United States)

    Ruan, Yunze; Xue, Chao; Zhang, Jian; Li, Rong; Shen, Qirong

    2014-01-01

    Our previous work demonstrated that application of a bio-organic fertilizer (BIO) to a banana mono-culture orchard with serious Fusarium wilt disease effectively decreased the number of soil Fusarium sp. and controlled the soil-borne disease. Because bacteria are an abundant and diverse group of soil organisms that responds to soil health, deep 16 S rRNA pyrosequencing was employed to characterize the composition of the bacterial community to investigate how it responded to BIO or the application of other common composts and to explore the potential correlation between bacterial community, BIO application and Fusarium wilt disease suppression. After basal quality control, 137,646 sequences and 9,388 operational taxonomic units (OTUs) were obtained from the 15 soil samples. Proteobacteria, Acidobacteria, Bacteroidetes, Gemmatimonadetes and Actinobacteria were the most frequent phyla and comprised up to 75.3% of the total sequences. Compared to the other soil samples, BIO-treated soil revealed higher abundances of Gemmatimonadetes and Acidobacteria, while Bacteroidetes were found in lower abundance. Meanwhile, on genus level, higher abundances compared to other treatments were observed for Gemmatimonas and Gp4. Correlation and redundancy analysis showed that the abundance of Gemmatimonas and Sphingomonas and the soil total nitrogen and ammonium nitrogen content were higher after BIO application, and they were all positively correlated with disease suppression. Cumulatively, the reduced Fusarium wilt disease incidence that was seen after BIO was applied for 1-year might be attributed to the general suppression based on a shift within the bacteria soil community, including specific enrichment of Gemmatimonas and Sphingomonas. PMID:24871319

  19. Insertional mutagenesis in the vascular wilt pathogen Verticillium dahliae

    NARCIS (Netherlands)

    Santhanam, P.

    2014-01-01

    Vascular wilt diseases caused by soil-borne pathogens are among the most

    devastating plant diseases worldwide. The ascomycete fungus Verticillium dahliae

    causes vascular wilt diseases in hundreds of dicotyledonous plant species, including

    important crops such as eggplant,

  20. Potential of contact insecticides to control Xyleborus glabratus (Coleoptera: Curculionidae), a vector of laurel wilt disease in avocados.

    Science.gov (United States)

    Carrillo, Daniel; Crane, Jonathan H; Peña, Jorge E

    2013-12-01

    Xyleborus glabratus Eichhoff (Coleoptera: Curculionidae: Scolytinae) is an invasive ambrosia beetle that vectors laurel wilt, a new disease that threatens avocado and other species in the Lauraceae Family. The lethal concentrations (LC50 & 90) of nine commercial insecticides to X. glabratus were determined by using a bolt-dip bioassay. Different formulations of bifenthrin, permethrin, fenpropathrin, z-cypermethrin + bifenthrin, 1-cyhalothrin + thiamethoxam, malathion, chlorpyrifos, carbaryl, and methomyl were tested. Four concentrations of each insecticide were tested (0.5, 0.1, 0.03, and 0.01 of the label rate) and with water as a control. Beetles were exposed to treated bolts and mortality registered 48 h later. After 2 wk, bolts were destructively sampled to determine the number of beetles that constructed galleries and were alive inside the wood. Probit analysis was used to determine the LC50 & 90. Six pesticides were applied directly to the trunk and limbs of avocado trees in a commercial grove. Limbs of treated trees were cut weekly after the application and exposed to X. glabratus to determine the number of beetles boring into the logs. The toxicity of pesticides to X. glabratus was greatly reduced 2 wk after application. Among the tested pesticides, malathion and z-cypermethrin + bifenthrin provided the best suppression of X. glabratus. Among the insecticides registered for use in avocado, fenpropathrin and malathion were the most effective in protecting trees from attack by X. glabratus. Other pesticides that are currently not registered for use in avocados could be useful for managing this ambrosia beetle.

  1. In vitro co-cultures of Pinus pinaster with Bursaphelenchus xylophilus: a biotechnological approach to study pine wilt disease.

    Science.gov (United States)

    Faria, Jorge M S; Sena, Inês; Vieira da Silva, Inês; Ribeiro, Bruno; Barbosa, Pedro; Ascensão, Lia; Bennett, Richard N; Mota, Manuel; Figueiredo, A Cristina

    2015-06-01

    Co-cultures of Pinus pinaster with Bursaphelenchus xylophilus were established as a biotechnological tool to evaluate the effect of nematotoxics addition in a host/parasite culture system. The pinewood nematode (PWN), Bursaphelenchus xylophilus, the causal agent of pine wilt disease (PWD), was detected for the first time in Europe in 1999 spreading throughout the pine forests in Portugal and recently in Spain. Plant in vitro cultures may be a useful experimental system to investigate the plant/nematode relationships in loco, thus avoiding the difficulties of field assays. In this study, Pinus pinaster in vitro cultures were established and compared to in vivo 1 year-old plantlets by analyzing shoot structure and volatiles production. In vitro co-cultures were established with the PWN and the effect of the phytoparasite on in vitro shoot structure, water content and volatiles production was evaluated. In vitro shoots showed similar structure and volatiles production to in vivo maritime pine plantlets. The first macroscopic symptoms of PWD were observed about 4 weeks after in vitro co-culture establishment. Nematode population in the culture medium increased and PWNs were detected in gaps of the callus tissue and in cavities developed from the degradation of cambial cells. In terms of volatiles main components, plantlets, P. pinaster cultures, and P. pinaster with B. xylophilus co-cultures were all β- and α-pinene rich. Co-cultures may be an easy-to-handle biotechnological approach to study this pathology, envisioning the understanding of and finding ways to restrain this highly devastating nematode.

  2. High throughput phenotyping of tomato spotted wilt disease in peanuts using unmanned aerial systems and multispectral imaging

    Science.gov (United States)

    The amount of visible and near infrared light reflected by plants varies depending on their health. In this study, multispectral images were acquired by quadcopter for detecting tomato spot wilt virus amongst twenty genetic varieties of peanuts. The plants were visually assessed to acquire ground ...

  3. Current •·esearcb trends on coffee wilt disease tracheomycosis

    African Journals Online (AJOL)

    being implemented are sensitisation offarmers and civic leaders about the disease, urging farmers to cut and burn ltfi'ected .... required for formulation of an integrated control procedure. .... screening methods and evidence for the horizontal.

  4. Occurrence of Root Rot and Vascular Wilt Diseases in Roselle (Hibiscus sabdariffa L.) in Upper Egypt

    OpenAIRE

    Hassan, Naglaa; Shimizu, Masafumi; Hyakumachi, Mitsuro

    2014-01-01

    Roselle (Hibiscus sabdariffa L.) family Malvaceae is an important crop used in food, cosmetics and pharmaceutics industries. Roselle is cultivated mainly in Upper Egypt (Qena and Aswan governorates) producing 94% of total production. Root rot disease of roselle is one of the most important diseases that attack both seedlings and adult plants causing serious losses in crop productivity and quality. The main objective of the present study is to identify and characterize pathogens associated wit...

  5. Biological control of fusarium wilt of tomato by antagonist fungi and ...

    African Journals Online (AJOL)

    Yomi

    2012-01-16

    Jan 16, 2012 ... Key words: Biological control, fusarium wilt, tomato, antagonist fungi, cyanobacteria. INTRODUCTION ... severely affected by wilt disease caused by F. oxysporum f. sp. ..... Changing options for the control of deciduous fruit.

  6. Trichoderma asperellum strain T34 controls Fusarium wilt disease in tomato plants in soilless culture through competition for iron.

    Science.gov (United States)

    Segarra, Guillem; Casanova, Eva; Avilés, Manuel; Trillas, Isabel

    2010-01-01

    Trichoderma asperellum strain T34 has been reported to control the disease caused by Fusarium oxysporum f.sp. lycopersici (Fol) on tomato plants. To study the importance of iron concentration in the growth media for the activity and competitiveness of T34 and the pathogen, we tested four iron concentrations in the nutrient solution [1, 10, 100, and 1000 microM provided as EDTA/Fe(III)] in a biological control experiment with T34 and Fol in tomato plants. The reduction of the Fusarium-infected shoot by T34 was only significant at 10 microM Fe. We hypothesized that Fe competition is one of the key factors in the biocontrol activity exerted by T34 against Fol, as an increase in Fe concentration over 10 microM would lead to the suppression of T34 siderophore synthesis and thus inhibition of Fe competition with Fol. T34 significantly reduced the populations of Fol at all the doses of Fe assayed. In contrast, Fol enhanced the populations of T34 at 1 and 10 microM Fe. Nevertheless, several plant physiological parameters like net CO(2) assimilation (A), stomatal conductance (g(s)), relative quantum efficiency of PSII (Phi(PSII)), and efficiency of excitation energy capture by open PSII reactive centers (Fv'/Fm') demonstrated the protection against Fol damage by treatment with T34 at 100 microM Fe. The first physiological parameter affected by the disease progression was g(s). Plant dry weight was decreased by Fe toxicity at 100 and 1,000 microM. T34-treated plants had significantly greater heights and dry weights than control plants at 1,000 microM Fe, even though T34 did not reduce the Fe content in leaves or stems. Furthermore, T34 enhanced plant height even at the optimal Fe concentration (10 microM) compared to control plants. In conclusion, T. asperellum strain T34 protected tomato plants from both biotic (Fusarium wilt disease) and abiotic stress [Fe(III) toxic effects].

  7. First report of Fusarium wilt of alfalfa caused by Fusarium oxysporum f. sp. medicaginis in Wisconsin

    Science.gov (United States)

    Fusarium wilt, caused by Fusarium oxysporum f. sp. medicaginis, is an economically important vascular disease of alfalfa (Medicago sativa) throughout the world. Alfalfa plants with foliar wilt symptoms and reddish-brown arcs in roots consistent with Fusarium wilt were observed in disease assessment ...

  8. How to identify and manage oak wilt in Texas

    Science.gov (United States)

    D.N. Appel; R.S. Cameron; A.D. Wilson; J.D. Johnson

    2008-01-01

    Transporting unseasoned firewood from diseased red oaks is a potential means of spreading the oak wilt fungus. Oak wilt cannot be transmitted by burning infected firewood, but fungal mats may form on firewood in storage. Presently, no vectors have been proven to transmit the fungus from live oaks to other oak trees, but diseased wood fromany oak species should never be...

  9. Synergistic effects of plant defense elicitors and Trichoderma harzianum on enhanced induction of antioxidant defense system in tomato against Fusarium wilt disease.

    Science.gov (United States)

    Zehra, Andleeb; Meena, Mukesh; Dubey, Manish Kumar; Aamir, Mohd; Upadhyay, R S

    2017-11-02

    Plant defense against their pathogens can be induced by a complex network of different inducers. The present study investigates the synergistic effect of Trichoderma harzianum, exogenous salicylic acid (SA) and methyl jasmonate (MeJA) over the response and regulation of the antioxidant defense mechanisms and lipid peroxidation in tomato plants against Fusarium wilt disease. In the present work, tomato plants were infected by Fusarium oxysporum f. sp. lycopersici 3 days after inoculated with T. harzianum and/or sprayed daily for 3 days with chemical inducers (SA and MeJA). Plants were analysed at 0, 24, 48, 72 and 96 h after inoculation with Fusarium oxysporum f. sp. lycopersici. Infection of tomato plants by pathogen led to strong reduction in the dry weight of roots and shoots with the enhanced concentration of H 2 O 2 and varying degree of lipid peroxidation. Concurrently, exogenous SA, when applied with pathogen greatly enhanced H 2 O 2 content as well as activities of antioxidant enzymes except catalase (CAT) and ascorbate peroxidase (APx). The pathogen challenged plants pretreated with T. harzianum and MeJA together exhibited less lipid peroxidation and as well as the elevated level of ascorbic acid and enhanced activities of antioxidant enzymes. All applied treatments protected tomato seedlings against Fusarium wilt disease but the percentage of protection was found higher in plants pretreated with the combination of T. harzianum and chemical inducers.

  10. Phylogeography of pink pineapple mealybugs, Dysmicoccus brevipes (Cockerell) reveals the history of pineapple introduction and cultivation in China.

    Science.gov (United States)

    He, Y B; Zhan, R L; Sun, G M; Wu, J B; Zhao, Y L

    2015-08-19

    The pink pineapple mealybug (PPM), Dysmicoccus brevipes (Cockerell) (Hemiptera: Pseudococcidae), is a widespread plant-sucking insect of considerable concern because it transmits the pineapple mealybug wilt-associated virus. Its distribution is closely linked with its host, the pineapple [Ananas comosus (L.) Merrill] because of its wingless and parthenogenetic characteristics. To investigate the history of D. brevipes introduction and the cultivation of pineapple in China, samples of D. brevipes were collected from the main pineapple production region in China, and from Thailand, and the mitochondrial cytochrome c oxidase subunit I (COI) gene was analyzed. Homologous sequences of D. brevipes COI from Brazil, Thailand, and Philippines that are deposited in GenBank were compared. Phylogenetic analyses suggest there are close genetic relationships between PPM populations from Hawaii, Brazil, the Philippines, and from Thailand and China, which probably originate from South America. It is suggested that most PPMs in China were introduced from South America by way of Southeast Asia, being accompanied by the pineapple seedling. Conversely, some PPMs represented by Haplotype-WN from Wanning of China, and Lampang of Thailand were found to differ greatly from populations in Hawaii, Brazil, the Philippines, Thailand, and China. It is possible that another route was used for the introduction and distribution of pineapple, or that pineapple might have originated in Southeast Asia.

  11. Association mapping of resistance to Verticillium wilt in Gossypium ...

    African Journals Online (AJOL)

    Verticillium wilt is a major disease affecting the growth of cotton. For screening the resistant genes, 320 Gossypium hirsutum germplasms were evaluated in Verticillium nursery, and association mapping was used to detect the markers associated with the Verticillium wilt resistance. 106 microsatellite marker primer pairs ...

  12. Ambrosia beetles associated with laurel wilt of avocado

    Science.gov (United States)

    Redbay ambrosia beetle, Xyleborus glabratus, is an exotic wood-boring pest first detected in 2002 near Savannah, Georgia. The beetle’s dominant fungal symbiont, Raffaelea lauricola, is the pathogen that causes laurel wilt, a lethal disease of trees in the family Lauraceae. Laurel wilt has since spr...

  13. Preparing soft-bodied arthropods for arthropods for microscope examination: Mealybugs (Insects: Hemiptera: Pseudococcidae)

    Science.gov (United States)

    Proper identification of mealybugs (Hemiptera: Pseudococcidae) require preparation of the specimen on a microscope slide. This training video provides visual instruction on how to prepare mealybug specimens on microscope slides for examination and identification. Steps ranging from collection, spec...

  14. Recovery Plan for Laurel Wilt of Avocado

    Science.gov (United States)

    Laurel wilt kills American members of the Lauraceae plant family, including avocado (Persea americana). The disease threatens commercial avocado production in Florida, as well as the National Germplasm Repository for avocado in Miami (USDA-ARS). Elsewhere in the US, major (California) and minor comm...

  15. Management of Fusarium Wilt using mycolytic enzymes produced by ...

    African Journals Online (AJOL)

    Aghomotsegin

    Trichoderma strain to manage the Fusarium wilt disease of Cicer aritenum under in vitro conditions. We also studied ... antibiosis, competition, parasitism and cell lysis can ideally be ... hydrolytic enzymes associated with fungal cell wall lysis,.

  16. Biological Control of Bacterial Wilt in South East Asia

    OpenAIRE

    Arwiyanto, Triwidodo

    2014-01-01

    Bacterial wilt disease caused by Ralstonia solanacearum destroys many crops of different plant families in South East Asia despite many researches about the disease, and the availability of developed control method in other parts of the world. There is no chemical available for the bacterial wilt pathogen and biological control is then chosen as an alternative to save the crops. Most of the biological control studies were based on antagonism between biological control agent and the pathogen. ...

  17. First report of Pineapple mealybug wilt associated virus-1 in Ecuador

    Science.gov (United States)

    In Ecuador, where pineapple represents one of the most important export commodities, virus testing has been neglected. In July 2014, a total of twenty MD2 hybrid pineapple plants showing virus-like symptoms (Fig. 1) were collected from a commercial planting located at the border of Santo Domingo and...

  18. Bioinformatics analysis to assess potential risks of allergenicity and toxicity of HRAP and PFLP proteins in genetically modified bananas resistant to Xanthomonas wilt disease.

    Science.gov (United States)

    Jin, Yuan; Goodman, Richard E; Tetteh, Afua O; Lu, Mei; Tripathi, Leena

    2017-11-01

    Banana Xanthomonas wilt (BXW) disease threatens banana production and food security throughout East Africa. Natural resistance is lacking among common cultivars. Genetically modified (GM) bananas resistant to BXW disease were developed by inserting the hypersensitive response-assisting protein (Hrap) or/and the plant ferredoxin-like protein (Pflp) gene(s) from sweet pepper (Capsicum annuum). Several of these GM banana events showed 100% resistance to BXW disease under field conditions in Uganda. The current study evaluated the potential allergenicity and toxicity of the expressed proteins HRAP and PFLP based on evaluation of published information on the history of safe use of the natural source of the proteins as well as established bioinformatics sequence comparison methods to known allergens (www.AllergenOnline.org and NCBI Protein) and toxins (NCBI Protein). The results did not identify potential risks of allergy and toxicity to either HRAP or PFLP proteins expressed in the GM bananas that might suggest potential health risks to humans. We recognize that additional tests including stability of these proteins in pepsin assay, nutrient analysis and possibly an acute rodent toxicity assay may be required by national regulatory authorities. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

  19. Analysis of root-knot nematode and fusarium wilt disease resistance in cotton (Gossypium spp.) using chromosome substitution lines from two alien species.

    Science.gov (United States)

    Ulloa, M; Wang, C; Saha, S; Hutmacher, R B; Stelly, D M; Jenkins, J N; Burke, J; Roberts, P A

    2016-04-01

    Chromosome substitution (CS) lines in plants are a powerful genetic resource for analyzing the contribution of chromosome segments to phenotypic variance. In this study, a series of interspecific cotton (Gossypium spp.) CS lines were used to identify a new germplasm resource, and to validate chromosomal regions and favorable alleles associated with nematode or fungal disease resistance traits. The CS lines were developed in the G. hirsutum L. TM-1 background with chromosome or chromosome segment substitutions from G. barbadense L. Pima 3-79 or G. tomentosum. Root-knot nematode (Meloidogyne incognita) and fusarium wilt (Fusarium oxysporum f. sp. vasinfectum) (races 1 and 4) resistance alleles and quantitative trait loci (QTL) previously placed on cotton chromosomes using SSR markers in two interspecific recombinant inbred line populations were chosen for testing. Phenotypic responses of increased resistance or susceptibility in controlled inoculation and infested field assays confirmed the resistance QTLs, based on substitution with the positive or negative allele for resistance. Lines CS-B22Lo, CS-B04, and CS-B18 showed high resistance to nematode root-galling, confirming QTLs on chromosomes 4 and 22 (long arm) with resistance alleles from Pima 3-79. Line CS-B16 had less fusarium race 1-induced vascular root staining and higher percent survival than the TM-1 parent, confirming a major resistance QTL on chromosome 16. Lines CS-B(17-11) and CS-B17 had high fusarium race 4 vascular symptoms and low survival due to susceptible alleles introgressed from Pima 3-79, confirming the localization on chromosome 17 of an identified QTL with resistance alleles from TM1 and other resistant lines. Analyses validated regions on chromosomes 11, 16, and 17 harboring nematode and fusarium wilt resistance genes and demonstrated the value of CS lines as both a germplasm resource for breeding programs and as a powerful genetic analysis tool for determining QTL effects for disease

  20. 'Candidatus Phytoplasma noviguineense', a novel taxon associated with Bogia coconut syndrome and banana wilt disease on the island of New Guinea.

    Science.gov (United States)

    Miyazaki, Akio; Shigaki, Toshiro; Koinuma, Hiroaki; Iwabuchi, Nozomu; Rauka, Gou Bue; Kembu, Alfred; Saul, Josephine; Watanabe, Kiyoto; Nijo, Takamichi; Maejima, Kensaku; Yamaji, Yasuyuki; Namba, Shigetou

    2018-01-01

    Bogia coconut syndrome (BCS) is one of the lethal yellowing (LY)-type diseases associated with phytoplasma presence that are seriously threatening coconut cultivation worldwide. It has recently emerged, and is rapidly spreading in northern parts of the island of New Guinea. BCS-associated phytoplasmas collected in different regions were compared in terms of 16S rRNA gene sequences, revealing high identity among them represented by strain BCS-Bo R . Comparative analysis of the 16S rRNA gene sequences revealed that BCS-Bo R shared less than a 97.5 % similarity with other species of 'Candidatus Phytoplasma', with a maximum value of 96.08 % (with strain LY; GenBank accession no. U18747). This result indicates the necessity and propriety of a novel taxon for BCS phytoplasmas according to the recommendations of the IRPCM. Phylogenetic analysis was also conducted on 16S rRNA gene sequences, resulting in a monophyletic cluster composed of BCS-Bo R and other LY-associated phytoplasmas. Other phytoplasmas on the island of New Guinea associated with banana wilt and arecanut yellow leaf diseases showed high similarities to BCS-Bo R and were closely related to BCS phytoplasmas. Based on the uniqueness of their 16S rRNA gene sequences, a novel taxon 'Ca.Phytoplasma noviguineense' is proposed for these phytoplasmas found on the island of New Guinea, with strain BCS-Bo R (GenBank accession no. LC228755) as the reference strain. The novel taxon is described in detail, including information on the symptoms of associated diseases and additional genetic features of the secY gene and rp operon.

  1. Mapping crop diseases using survey data: The case of bacterial wilt in bananas in the East African highlands

    NARCIS (Netherlands)

    Bouwmeester, H.; Heuvelink, G.B.M.; Stoorvogel, J.J.

    2016-01-01

    Globally, crop diseases result in significant losses in crop yields. To properly target interventions to control crop diseases, it is important to map diseases at a high resolution. However, many surveys of crop diseases pose challenges to mapping because available observations are only proxies of

  2. Combining fluorescent Pseudomonas spp. strains to enhance suppression of fusarium wilt of radish

    NARCIS (Netherlands)

    Boer, Marjan de; Sluis, Ientse van der; Loon, L.C. van; Bakker, P.A.H.M.

    1999-01-01

    Fusarium wilt diseases, caused by the fungus Fusarium oxysporum, lead to significant yield losses of crops. One strategy to control fusarium wilt is the use of antagonistic, root-colonizing Pseudomonas spp. It has been demonstrated that different strains of these bacteria suppress disease by

  3. Conditioning of mealybug (Hemiptera: Pseudococcidae) by Scanning Electron Microscopy

    International Nuclear Information System (INIS)

    Palma-Jimenez, Melissa; Blanco-Meneses, Monica

    2015-01-01

    The cleaning and correct observation of the mealybug specimens was determined by the conditioning methodology. The research was done in the Laboratorio del Centro de Investigacion en Estructuras Microscopicas (CIEMIC) of the Universidad de Costa Rica during the year 2012. A gradual improvement for the observation of the ultrastructures through the Scanning Electron Microscope was evidenced by the implementation of four types of methodologies. Each process was described in detail. The incorporation of 10% xylene (in some cases have been viable using ethanol at 95-100% ) was allowed to remove the wax from the body of the insect, to avoid this the collapse and to observe specific ultrastructures of the individual, they were the best results. The methodology used has reduced the time and costs in future taxonomic research of mealybug. (author) [es

  4. Effects of Endobacterium (Stenotrophomonas maltophilia on Pathogenesis-Related Gene Expression of Pine Wood Nematode (Bursaphelenchus xylophilus and Pine Wilt Disease

    Directory of Open Access Journals (Sweden)

    Long-Xi He

    2016-05-01

    Full Text Available Pine wilt disease (PWD caused by the pine wood nematode (PWN, Bursaphelenchus xylophilus, is responsible for devastating epidemics in pine trees in Asia and Europe. Recent studies showed that bacteria carried by the PWN might be involved in PWD. However, the molecular mechanism of the interaction between bacteria and the PWN remained unclear. Now that the whole genome of B. xylophilus (Bursaphelenchus xylophilus is published, transcriptome analysis is a unique method to study the role played by bacteria in PWN. In this study, the transcriptome of aseptic B. xylophilus, B. xylophilus treated with endobacterium (Stenotrophomonas maltophilia NSPmBx03 and fungus B. xylophilus were sequenced. We found that 61 genes were up-regulated and 830 were down-regulated in B. xylophilus after treatment with the endobacterium; 178 genes were up-regulated and 1122 were down-regulated in fungus B. xylophilus compared with aseptic B. xylophilus. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analyses were used to study the significantly changed biological functions and pathways for these differentially expressed genes. Many pathogenesis-related genes, including glutathinone S-transferase, pectate lyase, ATP-binding cassette transporter and cytochrome P450, were up-regulated after B. xylophilus were treated with the endobacterium. In addition, we found that bacteria enhanced the virulence of PWN. These findings indicate that endobacteria might play an important role in the development and virulence of PWN and will improve our understanding of the regulatory mechanisms involved in the interaction between bacteria and the PWN.

  5. Effects of Endobacterium (Stenotrophomonas maltophilia) on Pathogenesis-Related Gene Expression of Pine Wood Nematode (Bursaphelenchus xylophilus) and Pine Wilt Disease

    Science.gov (United States)

    He, Long-Xi; Wu, Xiao-Qin; Xue, Qi; Qiu, Xiu-Wen

    2016-01-01

    Pine wilt disease (PWD) caused by the pine wood nematode (PWN), Bursaphelenchus xylophilus, is responsible for devastating epidemics in pine trees in Asia and Europe. Recent studies showed that bacteria carried by the PWN might be involved in PWD. However, the molecular mechanism of the interaction between bacteria and the PWN remained unclear. Now that the whole genome of B. xylophilus (Bursaphelenchus xylophilus) is published, transcriptome analysis is a unique method to study the role played by bacteria in PWN. In this study, the transcriptome of aseptic B. xylophilus, B. xylophilus treated with endobacterium (Stenotrophomonas maltophilia NSPmBx03) and fungus B. xylophilus were sequenced. We found that 61 genes were up-regulated and 830 were down-regulated in B. xylophilus after treatment with the endobacterium; 178 genes were up-regulated and 1122 were down-regulated in fungus B. xylophilus compared with aseptic B. xylophilus. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analyses were used to study the significantly changed biological functions and pathways for these differentially expressed genes. Many pathogenesis-related genes, including glutathinone S-transferase, pectate lyase, ATP-binding cassette transporter and cytochrome P450, were up-regulated after B. xylophilus were treated with the endobacterium. In addition, we found that bacteria enhanced the virulence of PWN. These findings indicate that endobacteria might play an important role in the development and virulence of PWN and will improve our understanding of the regulatory mechanisms involved in the interaction between bacteria and the PWN. PMID:27231904

  6. DETECTING FORESTS DAMAGED BY PINE WILT DISEASE AT THE INDIVIDUAL TREE LEVEL USING AIRBORNE LASER DATA AND WORLDVIEW-2/3 IMAGES OVER TWO SEASONS

    Directory of Open Access Journals (Sweden)

    Y. Takenaka

    2017-10-01

    Full Text Available Pine wilt disease is caused by the pine wood nematode (Bursaphelenchus xylophilus and Japanese pine sawyer (Monochamus alternatus. This study attempted to detect damaged pine trees at different levels using a combination of airborne laser scanning (ALS data and high-resolution space-borne images. A canopy height model with a resolution of 50 cm derived from the ALS data was used for the delineation of tree crowns using the Individual Tree Detection method. Two pan-sharpened images were established using the ortho-rectified images. Next, we analyzed two kinds of intensity-hue-saturation (IHS images and 18 remote sensing indices (RSI derived from the pan-sharpened images. The mean and standard deviation of the 2 IHS images, 18 RSI, and 8 bands of the WV-2 and WV-3 images were extracted for each tree crown and were used to classify tree crowns using a support vector machine classifier. Individual tree crowns were assigned to one of nine classes: bare ground, Larix kaempferi, Cryptomeria japonica, Chamaecyparis obtusa, broadleaved trees, healthy pines, and damaged pines at slight, moderate, and heavy levels. The accuracy of the classifications using the WV-2 images ranged from 76.5 to 99.6 %, with an overall accuracy of 98.5 %. However, the accuracy of the classifications using the WV-3 images ranged from 40.4 to 95.4 %, with an overall accuracy of 72 %, which suggests poorer accuracy compared to those classes derived from the WV-2 images. This is because the WV-3 images were acquired in October 2016 from an area with low sun, at a low altitude.

  7. Bacterial wilt of potato (Ralstonia solanacearum race 3, biovar 2): disease management, pathogen survival and possible eradication

    NARCIS (Netherlands)

    Messiha, N.A.S.

    2006-01-01

    Potato brown rot, caused by Ralstonia solanacearum race 3 biovar 2 (Phylovar II, sequevar 1), is a serious endemic disease in the Nile Delta of Egypt. It is a quarantine disease in the EU, and export of potatoes from

  8. Genetic variation in native populations of the laurel wilt pathogen, Raffaelea lauricola , in Taiwan and Japan and the introduced population in the United States

    Science.gov (United States)

    Caroline E. Wuest; Thomas C. Harrington; Stephen W. Fraedrich; Hye-Young Yun; Sheng-Shan Lu

    2017-01-01

    Laurel wilt is a vascular wilt disease caused by Raffaelea lauricola, a mycangial symbiont of an ambrosia beetle, Xyleborus glabratus. The fungus and vector are native to Asia but were apparently introduced to the Savannah, GA, area 15 or more years ago. Laurel wilt has caused widespread mortality on redbay (Persea borbonia) and other members of the Lauraceae in the...

  9. Recovery plan for laurel wilt of avocado, caused by Raffaelea lauricola

    Science.gov (United States)

    Laurel wilt kills American members of the Lauraceae plant family, including avocado (Persea americana), an important commercial fruit crop. The disease threatens commercial production in the US and other countries, and currently impacts the avocado industry in Florida. As laurel wilt spreads, the N...

  10. Identification of potential insect vectors of the Cape Saint Paul Wilt Disease of coconut in Ghana by PCR

    Directory of Open Access Journals (Sweden)

    Pilet Fabian

    2009-03-01

    Full Text Available The vector of the phytoplasma responsible for the coconut lethal yellowing disease in West Africa is unknown to date. However, it is known that phytoplasmas are transmitted by leafhoppers and planthoppers, which are supposed to be the only ones able to inject the phytoplasma in the phloem. Whereas the presence of phytoplasma in the insect does not prove its capacity to transmit the disease. We have tested a large number of insects for the presence of phytoplamas by PCR (direct PCR and Nested PCR using both primer pairs specific for all phytoplasmas and those specific for the coconut lethal yellowing disease phytoplasma. In effect the evidence of one or several species carrying the phytoplasma would direct us on the insects to focus on in our transmission cages trials.

  11. Distinct roles for soil fungal and bacterial communities associated with the suppression of vanilla Fusarium wilt disease

    NARCIS (Netherlands)

    Xiong, Wu; Li, Rong; Ren, Yi; Liu, Chen; Zhao, Qingyun; Wu, Huasong; Jousset, Alexandre; Shen, Qirong

    2017-01-01

    Characterizing microbial communities associated with disease-suppressive soil is an important first step toward understanding the potential of microbiota to protect crops against plant pathogens. In the present study, we compared microbial communities in suppressive- and conducive-soils associated

  12. Banana Xanthomonas wilt in Ethiopia: Occurrence and insect vector ...

    African Journals Online (AJOL)

    Bacterial wilt caused by Xanthomonas vasicola pv. musacearum (Xvm) is an important disease of enset and banana in south and south-western Ethiopia where, the diversity of the insect fauna on banana inflorescences was unknown and the role of insects as vectors of the disease had not been studied. The objectives of ...

  13. Bacterial Wilt in China: History, Current Status, and Future Perspectives

    Science.gov (United States)

    Jiang, Gaofei; Wei, Zhong; Xu, Jin; Chen, Huilan; Zhang, Yong; She, Xiaoman; Macho, Alberto P.; Ding, Wei; Liao, Boshou

    2017-01-01

    Bacterial wilt caused by plant pathogenic Ralstonia spp. is one of the most important diseases affecting the production of many important crops worldwide. In China, a large scientific community has been dedicated to studying bacterial wilt and its causative agent, Ralstonia pseudosolanacearum and R. solanacearum. Most of their work was published in Chinese, which has hindered international communication and collaboration in this field. In this review, we summarize the status of knowledge on geographical distribution, diversity, and host range of Ralstonia spp., as well as, the impact of bacterial wilt on important crops and disease control approaches, in China. We present areas of research and publications by Chinese scientists and propose the promotion of collaborative research within China and with the international community. PMID:28955350

  14. Male-produced aggregation pheromone of Carpophilus sayi, a nitidulid vector of oak wilt disease, and pheromonal comparison with Carpophilus lugubris

    Science.gov (United States)

    Robert J. Bartelt; John F. Kyhl; Angie K. Ambourn; Jennifer Juzwik; Steven J. Seybold

    2004-01-01

    Carpophilus sayi, a nitidulid beetle vector of the oak wilt fungus, Ceratocystis fagacearum, was shown to have a male-produced aggregation pheromone. Six male-specific chemicals were identified from collections of volatiles. The two major compounds were (2E,4E,6E,8E)-3,5-dimethyl-7-ethyl-2,4,6,8- undecatetraene and (2E,4E,6E,8E...

  15. Reduction of Fusarium wilt in watermelon by Pseudomonas chlororaphis PCL1391 and P. fluorescens WCS365

    Directory of Open Access Journals (Sweden)

    G.T. Tziros

    2007-12-01

    Full Text Available Fusarium wilt of watermelon (Citrullus lanatus caused by Fusarium oxysporum f. sp. niveum is a devastatine soil-borne disease that causes extensive losses throughout the world. Two known Pseudomonas biocontrol strains were used separately and in combination to assess their antagonistic effectiveness against F. oxysporum f. sp. niveum in pot experiments. P. chlororaphis PCL1391 signifi cantly reduced disease severity. P. fl uorescens WCS365 was less effective in disease suppression, while a combination of the two bacteria had intermediate effects. The biological control of Fusarium wilt with P. chlororaphis offers a potentially useful tool in an integrated pest management program to control Fusarium wilt of watermelon.

  16. Molecular identification of Fusarium spp. causing wilt of chickpea and the first report of Fusarium redolens in Turkey

    Science.gov (United States)

    Chickpea (Cicer arietinum L.) is an important food legume crop and Fusarium wilt caused by Fusarium oxysporum f. sp. ciceris is one of the most important diseases of chickpea in Turkey. Fusarium redolens is known to cause wilt-like disease of chickpea in other countries, but has not been reported fr...

  17. Evaluation of tomato rootstocks and its use to control bacterial wilt diseaseAvaliação de porta-enxertos de tomateiro e o uso da enxertia no controle da murcha bacteriana

    Directory of Open Access Journals (Sweden)

    Francisco Ferraz Laranjeira

    2012-05-01

    Full Text Available Tomato plants are susceptible to bacterial wilting, which causes production losses varying from 10 to 100 %. A method for controlling this disease is the use of grafting on resistant rootstocks. This work had the objective of evaluating tomato genotypes for the resistance to Ralstonia solanacearum and the grafting technique as an alternative for the bacterial wilt control in the region of Recôncavo Baiano, Brazil. To evaluate the resistance to R. solanacearum, four local genotypes, collected in different regions of Bahia, the cv. Santa Clara as a susceptible treatment, and the Hawaii 7996 (H7996, as a resistant treatment were studied. For the evaluation of grafting method for control of bacterial wilt, the H7996 was used as rootstock, and the cvs. Santa Clara, Santa Cruz Kada, and Débora Plus were used as the scion plants. Both experiments were evaluated in an area infested with R. solanacearum, for a period of 65 days for the selection of the rootstocks and 45 days for the evaluation of the grafting method. Only the H7996 can be recommended as a R. solanacearum resistant rootstock. The other genotypes showed susceptibility to the pathogen. The grafting on the H7996 did not show incompatibility with the scion tomato cultivars tested and reached 100 % control of the bacterial wilt disease, for all treatments, suggesting that this method can be used as an alternative for the bacterial wilt control, allowing the production of susceptible tomato cultivars in areas infested with R. solanacearum A suscetibilidade do tomateiro à murcha bacteriana (Ralstonia solanacearum causa perdas que vão de 10 a 100 % na produção e uma das alternativas de controle que vem sendo utilizada é a enxertia com porta-enxerto resistente. Este trabalho teve o objetivo avaliar genótipos de tomateiro quanto à resistência a R. solanacearum e a enxertia como alternativa para o controle da murcha bacteriana do tomateiro na região do Recôncavo Baiano. Para avalia

  18. Effect of solarization with fresh chicken manure on verticillium wilt ...

    African Journals Online (AJOL)

    The present study was carried out to evaluate the effect of reducing wilt disease through the medium of fresh chicken manure (FCM) mixed with soil before solarized and then artificial Verticillium dahliae (V.d) inoculation on yield of eggplant (Solanum melongena L.) under field conditions. According to the splitplot design, ...

  19. (SRAP) markers linked to bacterial wilt resistance genes i

    African Journals Online (AJOL)

    SAM

    2014-03-19

    Mar 19, 2014 ... Bacterial wilt caused by Ralstonia solanacearum is one of the most economically important diseases affecting potato (Solanum tuberosum). It is necessary to develop more molecular markers for potential use in potato genetic research. A highly resistant primitive cultivated species Solanum phureja was.

  20. REACTION OF Musa balbisiana TO BANANA BACTERIAL WILT ...

    African Journals Online (AJOL)

    Prof. Adipala Ekwamu

    2Makerere University, Department of Agricultural Production, P. O. Box 7062, Kampala, Uganda. Corresponding author: kumalfred@gmail.com. (Received 7 February, 2012; accepted 3 September, 2013). ABSTRACT. Banana bacterial wilt (Xanthomonas campestris) is an emerging disease of bananas in Uganda.

  1. Anaerobic soil disinfestation for controlling Fusarium wilt in strawberies

    Science.gov (United States)

    A strategy to apply a high rate of carbon resource in the conduct of a fall bed anaerobic soil disinfestation (ASD) treatment did not provide effective control of Fusarium wilt in California strawberries. The lack of disease control efficacy resulted from an increase in soil populations of the caus...

  2. Mechanical transmission and survival of bacterial wilt on enset ...

    African Journals Online (AJOL)

    The transmission of enset bacterial wilt with contaminated knives and the survival of the causal agent in soil and enset plant debris was studied at the Awassa Agricultural Research Center, Awassa, Ethiopia. Contaminated knives were found to transmit the pathogen from infected to healthy plants. Disease symptoms were ...

  3. Laurel wilt: A global threat to avocado production

    Science.gov (United States)

    Laurel wilt kills American members of the Lauraceae plant family, including avocado (Persea americana). The disease threatens commercial avocado production in Florida, as well as the National Germplasm Repository for avocado in Miami (USDA-ARS). Elsewhere in the US, major (California) and minor comm...

  4. Fusarium Wilt Affecting Chickpea Crop

    Directory of Open Access Journals (Sweden)

    Warda Jendoubi

    2017-03-01

    Full Text Available Chickpea (Cicer arietinum L. contributes 18% of the global production of grain legume and serves as an important source of dietary protein. An important decrease in cropping area and production has been recorded during the last two decades. Several biotic and abiotic constraints underlie this decrease. Despite the efforts deployed in breeding and selection of several chickpea varieties with high yield potential that are tolerant to diseases, the situation has remained the same for the last decade. Fusarium wilt caused by Fusarium oxysporum f. sp. ciceris (Foc is the major soilborne fungus affecting chickpeas globally. Fusarium wilt epidemics can devastate crops and cause up to 100% loss in highly infested fields and under favorable conditions. To date, eight pathogenic races of Foc (races 0, 1A, 1B/C, 2, 3, 4, 5 and 6 have been reported worldwide. The development of resistant cultivars is the most effective method to manage this disease and to contribute to stabilizing chickpea yields. Development of resistant varieties to fusarium wilt in different breeding programs is mainly based on conventional selection. This method is time‐consuming and depends on inoculum load and specific environmental factors that influence disease development. The use of molecular tools offers great potential for chickpea improvement, specifically by identifying molecular markers closely linked to genes/QTLs controlling fusarium wilt.

  5. Bacteriophage-Based Bacterial Wilt Biocontrol for an Environmentally Sustainable Agriculture

    OpenAIRE

    ?lvarez, Bel?n; Biosca, Elena G.

    2017-01-01

    Bacterial wilt diseases caused by Ralstonia solanacearum, R. pseudosolanacearum, and R. syzygii subsp. indonesiensis (former R. solanacearum species complex) are among the most important plant diseases worldwide, severely affecting a high number of crops and ornamentals. Difficulties of bacterial wilt control by non-biological methods are related to effectiveness, bacterial resistance and environmental impact. Alternatively, a great many biocontrol strategies have been carried out, with the a...

  6. Fusarium oxysporum and the Fusarium Wilt Syndrome.

    Science.gov (United States)

    Gordon, Thomas R

    2017-08-04

    The Fusarium oxysporum species complex (FOSC) comprises a multitude of strains that cause vascular wilt diseases of economically important crops throughout the world. Although sexual reproduction is unknown in the FOSC, horizontal gene transfer may contribute to the observed diversity in pathogenic strains. Development of disease in a susceptible crop requires F. oxysporum to advance through a series of transitions, beginning with spore germination and culminating with establishment of a systemic infection. In principle, each transition presents an opportunity to influence the risk of disease. This includes modifications of the microbial community in soil, which can affect the ability of pathogen propagules to survive, germinate, and infect plant roots. In addition, many host attributes, including the composition of root exudates, the structure of the root cortex, and the capacity to recognize and respond quickly to invasive growth of a pathogen, can impede development of F. oxysporum.

  7. Identification of resistant sources in chickpea against fusarium wilt

    International Nuclear Information System (INIS)

    Ahmad, M.A.; Ayub, N.; Akram, A.

    2010-01-01

    Wilt caused by Fusarium oxysporum Schlechtend.Fr. f. sp. ciceris is a devastating disease of chickpea in Pakistan. In the present study 321 genotypes from different sources were evaluated under controlled condition to identify genetic sources of resistance against this disease at seedling and reproductive stage. Disease reaction at two stages revealed considerable variation among the genotypes. At seedling stage disease incidence varied from 0 to 29.3% whereas at reproductive stage ranged from 0 to 57%. At seedling stage 173 genotypes were resistant, 54 were tolerant and 94 were susceptible, whereas at reproductive stage, 102 genotypes were resistant, 36 were tolerant and 183 were susceptible. Eighty two genotypes showed steady resistance at both stages. These genotypes may be exploited for the development of resistant cultivars against wilt. (author

  8. Fungal diversity associated with verticillium wilt of cotton

    International Nuclear Information System (INIS)

    Khaskheli, M.I.; Sun, J.L.; Li, F.

    2014-01-01

    The association of fungal diversity with Verticillium wilt is rarely known, which is important to know for the control of this detrimental disease. Our study is the preliminary attempt to find the associations of fungal diversity with Verticillium wilt and provides the baseline information for biological control. About 30 different fungi from soil and 23 from cotton plants were isolated and confirmed through molecular characterization. The colony forming unit (CFU)/g dry soil of fungi before and after planting cotton showed significant variation among all the fungi. The overall frequency of all fungi for soil after sowing was significantly higher than before sowing. A. alternata, F. equiseti, F. concentricum, A. flavus, F. proliferatum, and Chaetomium sp. associated with high resistance (Arcot-1) to Verticillium wilt, whereas, V. dahliae, A.niger and Paecilomyces sp., with high susceptible (Arcot-438) germplasm. However, T. basicola, C. ramotenellum and G. intermedia were isolated from both. Soil plating was comparatively easiest than soil dilution method for the determination of frequency percentage, however, later method is useful for the screening of single spore isolation. Most of the antagonistic species were screened from soil; nevertheless, Paecilomyces and Chaetomium spp. were screened from plant and soil. In vitro test of T. longibrachiatum. T. atroviride, Paecilomyces and T. viride showed the strongest efficacy against V. dahliae. These efficient bio-agents can be used as an effective tool for other future studies regarding to Verticillium wilt of cotton. (author)

  9. Complex of primary and secondary parasitoids (Hymenoptera: Encyrtidae and Signiphoridae) of Hypogeoccoccus spp. mealybugs (Hemiptera: Pseudococcidae) in the New World

    Science.gov (United States)

    Parasitoids, both primary and secondary (hyperparasitoids), of Hypogeococcus spp. mealybugs (Hemiptera: Pseudococcidae) are reviewed to report results of the surveys in the New World conducted during 2009–2017 for perspective natural enemies of the Harrisia cactus mealybug, Hypogeococcus sp., which ...

  10. Microbial associates of the vine mealybug Planococcus ficus (Hemiptera: Pseudococcidae) under different rearing conditions.

    Science.gov (United States)

    Iasur-Kruh, Lilach; Taha-Salaime, Leena; Robinson, Wyatt E; Sharon, Rakefet; Droby, Samir; Perlman, Steve J; Zchori-Fein, Einat

    2015-01-01

    Sap-feeding insects harbor diverse microbial endosymbionts that play important roles in host ecology and evolution, including contributing to host pest status. The vine mealybug, Planococcus ficus, is a serious pest of grapevines, vectoring a number of pathogenic grape viruses. Previous studies have shown that virus transmission is abolished when mealybugs are raised in the laboratory on potato. To examine the possible role of microbial symbionts in virus transmission, the archaeal, bacterial, and fungal microbiota of field and laboratory P. ficus were characterized using molecular and classical microbiological methods. Lab and field colonies of P. ficus harbored different microbiota. While both were dominated by the bacterial obligate nutritional symbionts Moranella and Tremblaya, field samples also harbored a third bacterium that was allied with cluster L, a lineage of bacterial symbionts previously identified in aphids. Archaea were not found in any of the samples. Fungal communities in field-collected mealybugs were dominated by Metschnikowia and Cladosporium species, while those from laboratory-reared mealybugs were dominated by Alternaria and Cladosporium species. In conclusion, this study has identified a diverse set of microbes, most of which appear to be facultatively associated with P. ficus, depending on environmental conditions. The role of various members of the mealybug microbiome, as well as how the host plant affects microbial community structure, remains to be determined.

  11. Molecular and Morphological Identification of Mealybug Species (Hemiptera: Pseudococcidae) in Brazilian Vineyards

    Science.gov (United States)

    Pacheco da Silva, Vitor C.; Bertin, Aline; Blin, Aurélie; Germain, Jean-François; Bernardi, Daniel; Rignol, Guylène; Botton, Marcos; Malausa, Thibaut

    2014-01-01

    Mealybugs (Hemiptera: Pseudococcidae) are pests constraining the international trade of Brazilian table grapes. They damage grapes by transmitting viruses and toxins, causing defoliation, chlorosis, and vigor losses and favoring the development of sooty mold. Difficulties in mealybug identification remain an obstacle to the adequate management of these pests. In this study, our primary aim was to identify the principal mealybug species infesting the major table grape-producing regions in Brazil, by morphological and molecular characterization. Our secondary aim was to develop a rapid identification kit based on species-specific Polymerase Chain Reactions, to facilitate the routine identification of the most common pest species. We surveyed 40 sites infested with mealybugs and identified 17 species: Dysmicoccus brevipes (Cockerell), Dysmicoccus sylvarum Williams and Granara de Willink, Dysmicoccus texensis (Tinsley), Ferrisia cristinae Kaydan and Gullan, Ferrisia meridionalis Williams, Ferrisia terani Williams and Granara de Willink, Phenacoccus baccharidis Williams, Phenacoccus parvus Morrison, Phenacoccus solenopsis Tinsley, Planococcus citri (Risso), Pseudococcus viburni (Signoret), Pseudococcus cryptus Hempel, four taxa closely related each of to Pseudococcus viburni, Pseudococcus sociabilis Hambleton, Pseudococcus maritimus (Ehrhorn) and Pseudococcus meridionalis Prado, and one specimen from the genus Pseudococcus Westwood. The PCR method developed effectively identified five mealybug species of economic interest on grape in Brazil: D. brevipes, Pl. citri, Ps. viburni, Ph. solenopsis and Planococcus ficus (Signoret). Nevertheless, it is not possible to assure that this procedure is reliable for taxa that have not been sampled already and might be very closely related to the target species. PMID:25062012

  12. Laboratory Evaluation of Different Insecticides against Hibiscus Mealybug, Maconellicoccus hirsutus (Hemiptera: Pseudococcidae

    Directory of Open Access Journals (Sweden)

    Samman Fatima

    2016-01-01

    Full Text Available Hibiscus mealybug, Maconellicoccus hirsutus (Hemiptera: Pseudococcidae, is the major pest of many vegetables, fruits, crops, and ornamental plants causing losses to the farmers and its control has been an issue of significance in the pest management. This study was aimed at evaluating different concentrations (0.06%, 0.1%, and 0.14% of Telsta, Advantage, Talstar, Imidacloprid, and their mixtures against hibiscus mealybug in the Laboratory of Systematics and Pest Management at University of Gujrat, Pakistan. The toxic effect was evaluated in the laboratory bioassay after 24 and 48 h of the application of insecticides. The highest mortality (95.83% was shown by Talstar and Talstar + Imidacloprid at the concentration of 0.14% after 48 h followed by Advantage + Talstar with 87.50% mortality at 0.14% concentration after 48 h of application. The study also showed that the least effective treatment observed was Advantage + Telsta with no mortality after 24 h and 25% mortality after 48 h at 0.14% concentration. The study revealed that the concentration 0.14% was highly effective in lowering the mealybug population and insecticide mixtures were effective in reducing mealybug density. The study emphasizes the use of such insecticide mixtures to develop better management strategy for mealybug populations attacking ornamental plants. However effects of such insecticide mixtures on other organisms and biological control agents should be checked under field conditions.

  13. Molecular and morphological identification of mealybug species (Hemiptera: Pseudococcidae in Brazilian vineyards.

    Directory of Open Access Journals (Sweden)

    Vitor C Pacheco da Silva

    Full Text Available Mealybugs (Hemiptera: Pseudococcidae are pests constraining the international trade of Brazilian table grapes. They damage grapes by transmitting viruses and toxins, causing defoliation, chlorosis, and vigor losses and favoring the development of sooty mold. Difficulties in mealybug identification remain an obstacle to the adequate management of these pests. In this study, our primary aim was to identify the principal mealybug species infesting the major table grape-producing regions in Brazil, by morphological and molecular characterization. Our secondary aim was to develop a rapid identification kit based on species-specific Polymerase Chain Reactions, to facilitate the routine identification of the most common pest species. We surveyed 40 sites infested with mealybugs and identified 17 species: Dysmicoccus brevipes (Cockerell, Dysmicoccus sylvarum Williams and Granara de Willink, Dysmicoccus texensis (Tinsley, Ferrisia cristinae Kaydan and Gullan, Ferrisia meridionalis Williams, Ferrisia terani Williams and Granara de Willink, Phenacoccus baccharidis Williams, Phenacoccus parvus Morrison, Phenacoccus solenopsis Tinsley, Planococcus citri (Risso, Pseudococcus viburni (Signoret, Pseudococcus cryptus Hempel, four taxa closely related each of to Pseudococcus viburni, Pseudococcus sociabilis Hambleton, Pseudococcus maritimus (Ehrhorn and Pseudococcus meridionalis Prado, and one specimen from the genus Pseudococcus Westwood. The PCR method developed effectively identified five mealybug species of economic interest on grape in Brazil: D. brevipes, Pl. citri, Ps. viburni, Ph. solenopsis and Planococcus ficus (Signoret. Nevertheless, it is not possible to assure that this procedure is reliable for taxa that have not been sampled already and might be very closely related to the target species.

  14. Comparative Microbiome Analysis of a Fusarium Wilt Suppressive Soil and a Fusarium Wilt Conducive Soil From the Châteaurenard Region

    Directory of Open Access Journals (Sweden)

    Katarzyna Siegel-Hertz

    2018-04-01

    Full Text Available Disease-suppressive soils are soils in which specific soil-borne plant pathogens cause only limited disease although the pathogen and susceptible host plants are both present. Suppressiveness is in most cases of microbial origin. We conducted a comparative metabarcoding analysis of the taxonomic diversity of fungal and bacterial communities from suppressive and non-suppressive (conducive soils as regards Fusarium wilts sampled from the Châteaurenard region (France. Bioassays based on Fusarium wilt of flax confirmed that disease incidence was significantly lower in the suppressive soil than in the conducive soil. Furthermore, we succeeded in partly transferring Fusarium wilt-suppressiveness to the conducive soil by mixing 10% (w/w of the suppressive soil into the conducive soil. Fungal diversity differed significantly between the suppressive and conducive soils. Among dominant fungal operational taxonomic units (OTUs affiliated to known genera, 17 OTUs were detected exclusively in the suppressive soil. These OTUs were assigned to the Acremonium, Chaetomium, Cladosporium, Clonostachys, Fusarium, Ceratobasidium, Mortierella, Penicillium, Scytalidium, and Verticillium genera. Additionally, the relative abundance of specific members of the bacterial community was significantly higher in the suppressive and mixed soils than in the conducive soil. OTUs found more abundant in Fusarium wilt-suppressive soils were affiliated to the bacterial genera Adhaeribacter, Massilia, Microvirga, Rhizobium, Rhizobacter, Arthrobacter, Amycolatopsis, Rubrobacter, Paenibacillus, Stenotrophomonas, and Geobacter. Several of the fungal and bacterial genera detected exclusively or more abundantly in the Fusarium wilt-suppressive soil included genera known for their activity against F. oxysporum. Overall, this study supports the potential role of known fungal and bacterial genera in Fusarium wilt suppressive soils from Châteaurenard and pinpoints new bacterial and fungal

  15. Effectiveness of composts and Trichoderma strains for control of Fusarium wilt of tomato

    Directory of Open Access Journals (Sweden)

    Yousra TAGHDI

    2015-09-01

    Full Text Available Fusarium wilt caused by Fusarium oxysporum f. sp. lycopersici (FOL is a major limiting disease in tomato production in Morocco. Commercial and locally produced Moroccan composts and peat were found to reduce Fusarium wilt in tomato plants. We explored the presence of Trichoderma strains in these materials, and in six soils sampled in the North West of Morocco, where a low incidence of Fusarium wilt had been previously observed. The most abundant Trichoderma-like fungus was selected from each soil, compost or peat sample. Twelve Trichoderma strains were isolated and identified molecularly. Trichoderma asperellum CT9 and Trichoderma virens ST11 showed the greatest overall antagonistic activity against FOL, Rhizoctonia solani, Botrytis cinerea and Pythium ultimum. The three strains evaluated in in planta tests, CT9, ST11 and T. virens ST10, reduced tomato Fusarium wilt, and strain ST11  also promoted growth of tomato plants.

  16. Soil Acidification Aggravates the Occurrence of Bacterial Wilt in South China

    Directory of Open Access Journals (Sweden)

    Chen Xu

    2017-04-01

    Full Text Available Soil acidification is a major problem in modern agricultural systems and is an important factor affecting the soil microbial community and soil health. However, little is known about the effect of soil acidification on soil-borne plant diseases. We performed a 4-year investigation in South China to evaluate the correlation between soil acidification and the occurrence of bacterial wilt. The results showed that the average soil pH in fields infected by bacterial wilt disease was much lower than that in non-disease fields. Moreover, the proportion of infected soils with pH lower than 5.5 was much higher than that of non-infected soils, and this phenomenon became more obvious as the area of bacterial wilt disease increased at soil pH lower than 5.5 from 2011 to 2014. Then, in a field pot experiment, bacterial wilt disease developed more quickly and severely in acidic conditions of pH 4.5, 5.0, and 5.5. These results indicate that soil acidification can cause the outbreak of bacterial wilt disease. Further experiments showed that acidic conditions (pH 4.5–5.5 favored the growth of the pathogen Ralstonia solanacearum but suppressed the growth and antagonistic activity of antagonistic bacteria of Pseudomonas fluorescens and Bacillus cereus. Moreover, acidic conditions of pH 5.5 were conducive to the expression of the virulence genes PopA, PrhA, and SolR but restrained resistance gene expression in tobacco. Finally, application of wood ash and lime as soil pH amendments improved soil pH and reduced the occurrence of bacterial wilt. Together, these findings improve our understanding of the correlation between soil acidification and soil-borne plant diseases and also suggest that regulation of soil acidification is the precondition and foundation of controlling bacterial wilt.

  17. Weed hosts of cotton mealybug, Phenacoccus solenopsis Tinsley (Hemiptera: Pseudococcidae).

    Science.gov (United States)

    Vennila, S; Prasad, Y G; Prabhakar, M; Agarwal, Meenu; Sreedevi, G; Bambawale, O M

    2013-03-01

    The exotic cotton mealybug, Phenacoccus solenopsis Tinsley (Hemiptera: Pseudococcidae) invaded India during 2006, and caused widespread infestation across all nine cotton growing states. P. solenopsis also infested weeds that aided its faster spread and increased severity across cotton fields. Two year survey carried out to document host plants of P. solenopsis between 2008 and 2010 revealed 27, 83, 59 and 108 weeds belonging to 8, 18, 10 and 32 families serving as alternate hosts at North, Central, South and All India cotton growing zones, respectively. Plant species of four families viz., Asteraceae, Amaranthaceae, Malvaceae and Lamiaceae constituted almost 50% of the weed hosts. While 39 weed species supported P. solenopsis multiplication during the cotton season, 37 were hosts during off season. Higher number of weeds as off season hosts (17) outnumbering cotton season (13) at Central over other zones indicated the strong carryover of the pest aided by weeds between two cotton seasons. Six, two and seven weed hosts had the extreme severity of Grade 4 during cotton, off and cotton + off seasons, respectively. Higher number of weed hosts of P. solenopsis were located at roadside: South (12) > Central (8) > North (3) zones. Commonality of weed hosts was higher between C+S zones, while no weed host was common between N+S zones. Paper furnishes the wide range of weed hosts of P. solenopsis, discusses their significance, and formulated general and specific cultural management strategies for nationwide implementation to prevent its outbreaks.

  18. Occurrence of new species of mealybug on cotton fields in the states of Bahia and Paraíba, Brazil

    Directory of Open Access Journals (Sweden)

    Carlos Alberto Domingues da Silva

    2012-01-01

    Full Text Available The cotton mealybug, Phenacoccus solenopsis Tinsley (Hemiptera: Pseudococcidae has been reported occurring in several countries causing severe losses in economically important crops, including cotton. Based on information reported by farmers in the regions of the Southwest and Middle São Francisco, Bahia and also in the regions of the Agreste and Semi-arid of the Paraiba State, high infestations of cotton mealybugs have occurred in these regions during the cotton season of 2007 and 2008. The cotton mealybug was identified as P. solenopsis and this represents the first record of this insect attacking cotton in Brazil.

  19. Control of Fusarium Wilt of Chili With Chitinolytic Bacteria

    Directory of Open Access Journals (Sweden)

    DWI SURYANTO

    2010-03-01

    Full Text Available Biological control of plant disease using antagonistic microorganism has been obtaining much attention and implemented for decades. One of the potential microorganisms used in this strategy is chitinolytic bacteria. Utilization of this bacteria ranges from cell life, enzymes, genes, or other metabolites. In this study, we examined the ability of chitinolytic bacteria as a biocontrol agent of Fusarium wilt of red chili (Capsicum annuum L. seedlings. The ability of chitinolytic bacteria to suppress the disease was evaluated by soaking red chili seeds in the bacterial isolates solution for 30 minutes prior seedling. Percentage of seedling of treated chili seed at end of study (4-weeks ranging from 46 to 82.14%. Relative reduction of the seedling damping-off was observed in all bacterial treatment ranged from 28.57 to 60.71%. Furthermore, manifestation of bacterial suppression to Fusarium wilt was also exhibited by increasing of seedling height (ranged from 7.33 to 7.87 cm compared to 6.88 cm and dry-weight (ranged from 2.7 to 4.3 mg compared to 2.3 mg. However, no significant effect was observed in leaf number. Then, from all chitinolytic isolates tested, BK08 was the most potential candidate for biological control agent of Fusarium wilt in chili seedling.

  20. Quantification of Fusarium oxysporum in fumigated soils by a newly developed real-time PCR assay to assess the efficacy of fumigants for Fusarium wilt disease in strawberry plants.

    Science.gov (United States)

    Li, Yuan; Mao, Liangang; Yan, Dongdong; Ma, Taotao; Shen, Jin; Guo, Meixia; Wang, Qiuxia; Ouyang, Canbin; Cao, Aocheng

    2014-11-01

    Two soil fumigants, chloropicrin (CP) and dimethyl disulfide (DMDS), were used to control Fusarium wilt disease (FWD) which caused large economic losses in strawberries. The fumigants were evaluated alone and in combination in a laboratory study and in strawberry greenhouses. Laboratory tests found that combinations of CP and DMDS indicated a positive synergistic activity on Fusarium oxysporum. A newly developed quantitative assay for F. oxysporum involving real-time PCR was used successfully to evaluate F. oxysporum control by the fumigants; it provided similar results to the selective medium but was less time-consuming and less labor intensive. Greenhouse trials revealed that the combination of CP and DMDS successfully suppressed the incidence of FWD and sharply reduced the population density of F. oxysporum, which significantly increased fruit branch number and maintained a good strawberry yield, higher than methyl bromide (MB) treatment. All of the treatments provided significantly better results than the non-treated control. This study confirms that the newly developed real-time PCR quantitative assay for F. oxysporum was suitable for the control efficacy evaluation of soil fumigants and that the novel fumigant combination of CP and DMDS offers a promising effective alternative to MB for the control of F. oxysporum in strawberry greenhouses. © 2013 Society of Chemical Industry.

  1. Molecular evidence for ongoing complementarity and horizontal gene transfer in endosymbiotic systems of mealybugs

    Directory of Open Access Journals (Sweden)

    Sergio eLópez-Madrigal

    2014-08-01

    Full Text Available Intracellular bacterial supply of essential amino acids is common among sap-feeding insects, thus complementing the scarcity of nitrogenous compounds in plant phloem. This is also the role of the two mealybug endosymbiotic systems whose genomes have been sequenced. In the nested endosymbiotic system from Planococcus citri (Pseudococcinae, Candidatus Tremblaya princeps and Candidatus Moranella endobia cooperate to synthesize essential amino acids, while in Phenacoccus avenae (Phenacoccinae this function is performed by its single endosymbiont Candidatus Tremblaya phenacola. However, little is known regarding the evolution of essential amino acid supplementation strategies in other mealybug systems. To address this knowledge gap, we screened for the presence of six selected loci involved in essential amino acid biosynthesis in five additional mealybug species. We found evidence of ongoing complementarity among endosymbionts from insects of subfamily Pseudococcinae, as well as horizontal gene transfer affecting endosymbionts from insects of family Phenacoccinae, providing a more comprehensive picture of the evolutionary history of these endosymbiotic systems. Additionally, we report two diagnostic motifs to help identify invasive mealybug species.

  2. Parasitoid complex of the mealybug Oracella acuta (Lobdell) (Hemiptera: Pseudococcidae), in Georgia, USA

    Science.gov (United States)

    Jiang-Hua Sun; Stephen R. Clarke; Gary L. Debarr; C. Wayne Berisford

    2004-01-01

    The parasitoid complex of the mealybug Oracella acuta (Lobdell) was examined in two field populations in Georgia in 1995-96. Allotropa n. sp. and Zarhopalus debarri Sun were the primary endoparasitoids emerging from 0. acuta. Adult abundance varied seasonally, with Allotropa...

  3. Molecular and morphological identification of the mealybug pest species, Phenacoccus solani Ferris (Hemiptera: Pseudococcidae), in Egypt

    Science.gov (United States)

    During the summer and autumn of 2016, heavy infestations of the mealybug, Phenacoccus solani Ferris (Hemiptera: Pseudococcidae), were observed on pumpkins, Cucurbita spp. (Cucurbitaceae). This was the first record of the species in Egypt. Several populations have been collected in various pumpkin fr...

  4. Scale insects, mealybugs, whiteflies and psyllids (Hemiptera, Sternorrhyncha) as prey of ladybirds. (Review)

    Czech Academy of Sciences Publication Activity Database

    Hodek, Ivo; Honěk, A.

    2009-01-01

    Roč. 51, č. 2 (2009), s. 232-243 ISSN 1049-9644 Grant - others:MzeČR(CZ) 002700604; GA ČR(CZ) GA522/08/1300 Institutional research plan: CEZ:AV0Z50070508 Keywords : scale insects * mealybugs * whiteflies Subject RIV: EH - Ecology, Behaviour Impact factor: 1.612, year: 2009

  5. A new class of mealybug pheromones: a hemiterpene ester in the sex pheromone of Crisicoccus matsumotoi

    Science.gov (United States)

    Tabata, Jun; Narai, Yutaka; Sawamura, Nobuo; Hiradate, Syuntaro; Sugie, Hajime

    2012-07-01

    Mealybugs, which include several agricultural pests, are small sap feeders covered with a powdery wax. They exhibit clear sexual dimorphism; males are winged but fragile and short lived, whereas females are windless and less mobile. Thus, sex pheromones emitted by females facilitate copulation and reproduction by serving as a key navigation tool for males. Although the structures of the hitherto known mealybug pheromones vary among species, they have a common structural motif; they are carboxylic esters of monoterpene alcohols with irregular non-head-to-tail linkages. However, in the present study, we isolated from the Matsumoto mealybug, Crisicoccus matsumotoi (Siraiwa), a pheromone with a completely different structure. Using gas chromatography-mass spectrometry and nuclear magnetic resonance spectroscopy, we identified the pheromone as 3-methyl-3-butenyl 5-methylhexanoate. Its attractiveness to males was confirmed in a series of field trapping experiments involving comparison between the isolated natural product and a synthetic sample. This is the first report of a hemiterpene mealybug pheromone. In addition, the acid moiety (5-methylhexanoate) appears to be rare in insect pheromones.

  6. Control of the cassava mealybug in Africa: lessons from a biological ...

    African Journals Online (AJOL)

    Control of the cassava mealybug in Africa: lessons from a biological control project. ... Such studies are needed in order to attribute the observed effects to various causes and to advance the science of biological control. ( 4) It is concluded that biological control is the basis ofiPM but cannot usually be manipulated by the ...

  7. Identification of grape cultivars and rootstocks with resistance to vine mealybug

    Science.gov (United States)

    Vine mealybug, an insect pest capable of causing direct and indirect damage to grape vineyards, costs California growers millions of dollars annually. Insecticide sprays used to manage the pest provide inconsistent results, and sustainable methods of control are needed. A previous study identified a...

  8. Incidence of a New Pest, the Cotton Mealybug Phenacoccus solenopsis Tinsley, on Sesame in North Ethiopia

    Directory of Open Access Journals (Sweden)

    Zenawi Gebregergis

    2018-01-01

    Full Text Available Sesame (Sesamum indicum is one of the most important cash crops grown extensively for its seeds in Ethiopia. Production of sesame in the country is very crucial in many aspects, but the invasion of the cotton mealybug, Phenacoccus solenopsis Tinsley, is becoming a big deal in its production. A survey for mealybug infestation was conducted during 2016 production season in 15 localities of “Kafta Humera” district so as to assess the incidence and severity of the pest. In each locality 2 sesame farms have been selected and 6 samples per farm (2 samples from the road sides, 2 from camp surrounding, and 2 from the central part of the farms have been checked. During the survey, “Bowal” and “Sherif Hamad” have scored the higher incidence and severity of mealybugs. Road sides and camp surrounding of the farms were shown to have severe infestation. Stony and oxen plowed farms were also intensively invaded with cotton mealybugs. The pest has different natural means to infest new areas; thus its control measure has to be developing timely.

  9. Fire ants protect mealybugs against their natural enemies by utilizing the leaf shelters constructed by the leaf roller Sylepta derogata.

    Directory of Open Access Journals (Sweden)

    Aiming Zhou

    Full Text Available The importance of mutualism is receiving more attention in community ecology. In this study, the fire ant Solenopsis invicta was found to take advantage of the shelters constructed by the leaf roller Sylepta derogata to protect mealybugs (Phenacoccus solenopsis against their natural enemies. This protective effect of fire ant tending on the survival of mealybugs in shelters was observed when enemies and leaf rollers were simultaneously present. Specifically, fire ants moved the mealybugs inside the shelters produced by S. derogata on enemy-infested plants. Compared with that in plants without ants, the survival of mealybugs in shelters in the presence of natural enemies in plants with ants markedly improved. Both the protection of ants and the shelters provided by leaf rollers did not affect the survival of mealybugs in the absence of enemies in plants. Ants and leaf rollers significantly improved the survival of mealybugs in predator-infested plants, whereas no such improvement was observed in parasitoid-infested ones.

  10. Bacteriophage-Based Bacterial Wilt Biocontrol for an Environmentally Sustainable Agriculture

    Directory of Open Access Journals (Sweden)

    Belén Álvarez

    2017-07-01

    Full Text Available Bacterial wilt diseases caused by Ralstonia solanacearum, R. pseudosolanacearum, and R. syzygii subsp. indonesiensis (former R. solanacearum species complex are among the most important plant diseases worldwide, severely affecting a high number of crops and ornamentals. Difficulties of bacterial wilt control by non-biological methods are related to effectiveness, bacterial resistance and environmental impact. Alternatively, a great many biocontrol strategies have been carried out, with the advantage of being environmentally friendly. Advances in bacterial wilt biocontrol include an increasing interest in bacteriophage-based treatments as a promising re-emerging strategy. Bacteriophages against the bacterial wilt pathogens have been described with either lytic or lysogenic effect but, they were proved to be active against strains belonging to R. pseudosolanacearum and/or R. syzygii subsp. indonesiensis, not to the present R. solanacearum species, and only two of them demonstrated successful biocontrol potential in planta. Despite the publication of three patents on the topic, until now no bacteriophage-based product is commercially available. Therefore, there is still much to be done to incorporate valid bacteriophages in an integrated management program to effectively fight bacterial wilt in the field.

  11. Bacteriophage-Based Bacterial Wilt Biocontrol for an Environmentally Sustainable Agriculture.

    Science.gov (United States)

    Álvarez, Belén; Biosca, Elena G

    2017-01-01

    Bacterial wilt diseases caused by Ralstonia solanacearum , R. pseudosolanacearum , and R. syzygii subsp. indonesiensis (former R. solanacearum species complex) are among the most important plant diseases worldwide, severely affecting a high number of crops and ornamentals. Difficulties of bacterial wilt control by non-biological methods are related to effectiveness, bacterial resistance and environmental impact. Alternatively, a great many biocontrol strategies have been carried out, with the advantage of being environmentally friendly. Advances in bacterial wilt biocontrol include an increasing interest in bacteriophage-based treatments as a promising re-emerging strategy. Bacteriophages against the bacterial wilt pathogens have been described with either lytic or lysogenic effect but, they were proved to be active against strains belonging to R. pseudosolanacearum and/or R. syzygii subsp. indonesiensis , not to the present R. solanacearum species, and only two of them demonstrated successful biocontrol potential in planta . Despite the publication of three patents on the topic, until now no bacteriophage-based product is commercially available. Therefore, there is still much to be done to incorporate valid bacteriophages in an integrated management program to effectively fight bacterial wilt in the field.

  12. Rhizobacteria induces resistance against Fusarium wilt of tomato by increasing the activity of defense enzymes

    Directory of Open Access Journals (Sweden)

    Hélvio Gledson Maciel Ferraz

    2014-09-01

    Full Text Available Fusarium wilt, caused by Fusarium oxysporum f.sp. lycopersici (Fol, is one of the most important diseases that affect tomato yield worldwide. This study investigated the potential of three antagonists, Streptomyces setonii (UFV 618, Bacillus cereus (UFV 592 and Serratia marcescens (UFV 252, and as positive control the hormone jasmonic acid (JA, to reduce Fusarium wilt symptoms and to potentiate the defense enzymes in the stem tissues of tomato plants infected by Fol. The seeds were microbiolized with each antagonist, and the soil was also drenched with them. The plants were sprayed with JA 48 h before Fol inoculation. The area under the Fusarium wilt index progress curve was reduced by 54, 48, 47 and 45% for the UFV 618, JA, UFV 592 and UFV 252 treatments, respectively. The three antagonists, and even the JA spray, efficiently reduced the Fusarium wilt symptoms on the tomato plant stems, which can be explained by the lower malondialdehyde concentration (an indication of oxidative damage to lipids in the plasma membranes and the greater activities of peroxidases, polyphenoloxidases, glucanases, chitinases, phenylalanine ammonia-lyases and lipoxygenases, which are commonly involved in host resistance against fungal diseases. These results present a novel alternative that can be used in the integrated management of Fusarium wilt on tomatoes.

  13. Using genetic information to inform Redbay restoration in Laurel Wilt epidemic areas

    Science.gov (United States)

    K.E. Smith; M.A. Hughes; C.S. Echt; S.A. Josserand; C.D. Nelson; J.M. Davis; J.A. Smith

    2017-01-01

    Laurel wilt disease is incited by the exotic fungus Raffaelea lauricola and transmitted by the Asian redbay ambrosia beetle (Xyleborus glabratus). The disease has spread from Savannah, Georgia in 2002 across the coastal southeast as far south as the Everglades, and in 2014 was discovered as far west as Texas. Mortality is severe, with locations in...

  14. Towards the development of a laurel wilt screening program in redbay (Persea borbonia)

    Science.gov (United States)

    Marc Hughes; Jason Smith

    2012-01-01

    Laurel wilt is a highly destructive disease of redbay (Persea borbonia (L.) Spreng.) and other Lauraceous natives in the southeastern United States. The disease and associated vector, the redbay ambrosia beetle (Xyleborus glabratus), has spread through the United States coastal plain. The presence of surviving and...

  15. Effect of insecticides on mealybug destroyer (Coleoptera: Coccinellidae) and parasitoid Leptomastix dactylopii (Hymenoptera: Encyrtidae), natural enemies of citrus mealybug (Homoptera: Pseudococcidae).

    Science.gov (United States)

    Cloyd, Raymond A; Dickinson, Amy

    2006-10-01

    In this study, we measured, under laboratory conditions, the direct and indirect effects of insecticides on mealybug destroyer, Cryptolaemus montrouzieri Mulsant (Coleoptera: Coccinellidae), and parasitoid Leptomastix dactylopii Howard (Hymenoptera: Encyrtidae), natural enemies of citrus mealybug, Planococcus citri (Risso) (Homoptera: Pseudococcidae). The adult stages of both natural enemies were exposed to sprays of the insecticides buprofezin, pyriproxyfen, flonicamid, acetamiprid, dinotefuran, and clothianidin at label-recommended rates to assess direct mortality after 24, 48, and 72 h, respectively. The effects of the insecticides on L. dactylopii parasitization rate and percentage of parasitoid emergence also were monitored using the label and 4x the recommended label rate. Dinotefuran was extremely detrimental to the adult parasitoid at the label rate with 100% mortality after 24 h. Buprofezin, pyriproxyfen, and flonicamid were not harmful to L. dactylopii when applied at the label rate. At 4x the recommended label rate, dinotefuran, acetamiprid, and clothianidin were all harmful to the parasitoid with 100% mortality 72 h after application. Both buprofezin and flonicamid were not toxic to L. dactylopii with 100% adult survival after 72 h. Pyriproxyfen and flonicamid, at both the label and 4x the recommended label rate, did not negatively affect L. dactylopii parasitization rate or percentage of parasitoid emergence. Acetamiprid, dinotefuran, and clothianidin were toxic to C. montrouzieri adults with 100% mortality after 48 h, whereas buprofezin, pyriproxyfen, and flonicamid demonstrated minimal (10-20% mortality after 48 h) harmful effects to the predator. Based on the results from our study, the indirect effects of the insect growth regulator (IGR) buprofezin were not decisive; however, the IGR pyriproxyfen and the insecticide flonicamid were not directly or indirectly harmful to the predator C. montrouzieri and parastioid L. dactylopii, indicating that

  16. Differential impacts of six insecticides on a mealybug and its coccinellid predator.

    Science.gov (United States)

    Barbosa, Paulo R R; Oliveira, Martin D; Barros, Eduardo M; Michaud, J P; Torres, Jorge B

    2018-01-01

    Broad-spectrum insecticides may disrupt biological control and cause pest resurgence due to their negative impacts on natural enemies. The preservation of sustainable pest control in agroecosystems requires parallel assessments of insecticide toxicity to target pests and their key natural enemies. In the present study, the leaf dipping method was used to evaluate the relative toxicity of six insecticides to the striped mealybug, Ferrisia dasylirii (Cockerell) (Hemiptera: Pseudococcidae) and its predator, Tenuisvalvae notata (Mulsant) (Coleoptera: Coccinellidae). Three neurotoxic insecticides, lambda-cyhalothrin, methidathion and thiamethoxam, caused complete mortality of both pest and predator when applied at their highest field rates. In contrast, lufenuron, pymetrozine and pyriproxyfen caused moderate mortality of third-instar mealybug nymphs, and exhibited low or no toxicity to either larvae or adults of the lady beetle. At field rates, lufenuron and pymetrozine had negligible effects on prey consumption, development or reproduction of T. notata, but adults failed to emerge from pupae when fourth instar larvae were exposed to pyriproxyfen. In addition, pyriproxyfen caused temporary sterility; T. notata females laid non-viable eggs for three days after exposure, but recovered egg fertility thereafter. Our results indicate that the three neurotoxic insecticides can potentially control F. dasylirii, but are hazardous to its natural predator. In contrast, lufenuron and pymetrozine appear compatible with T. notata, although they appear less effective against the mealybug. Although the acute toxicity of pyriproxyfen to T. notata was low, some pupal mortality and reduced egg fertility suggest that this material could impede the predator's numerical response to mealybug populations. Copyright © 2017 Elsevier Inc. All rights reserved.

  17. Sex Pheromone of the Cotton Mealybug, Phenacoccus solenopsis, with an Unusual Cyclobutane Structure.

    Science.gov (United States)

    Tabata, Jun; Ichiki, Ryoko T

    2016-11-01

    The cotton mealybug, Phenacoccus solenopsis, the distribution of which was formerly limited to Nearctic and Neotropical regions, recently invaded many countries in various regions including Asia, Africa, and the Pacific. More recently, P. solenopsis was newly recorded in Japan and is currently an emerging pest of agricultural crops. In this study, we determined the structure of a sex pheromone of P. solenopsis in order to develop an effective lure for monitoring this pest. From volatiles emitted by virgin adult females, we isolated a compound attractive to males. By means of coupled gas chromatography-mass spectrometry and nuclear magnetic resonance spectroscopy, we identified this as (2,2-dimethyl-3-isopropylidenecyclobutyl)methyl 3-methylbut-2-enoate. This compound was synthesized and shown to be attractive to male P. solenopsis. Analysis by gas chromatography using an enantioselective stationary phase and polarimetry analyses of the natural pheromone and synthetic enantiomers showed the natural compound to be the (R)-(-)-enantiomer. This compound is an ester of maconelliol, which has an unusual cyclobutane structure found in sex pheromones of other mealybug species, and senecioic acid, also found in the pheromones of other mealybug species. However, this is the first example of the ester of maconelliol and senecioic acid as a natural product.

  18. Investigating Biological Control Agents for Controlling Invasive Populations of the Mealybug Pseudococcus comstocki in France.

    Directory of Open Access Journals (Sweden)

    Thibaut Malausa

    Full Text Available Pseudococcus comstocki (Hemiptera: Pseudococcidae is a mealybug species native to Eastern Asia and present as an invasive pest in northern Italy and southern France since the start of the century. It infests apple and pear trees, grapevines and some ornamental trees. Biocontrol programmes against this pest proved successful in central Asia and North America in the second half of the 20th century. In this study, we investigated possible biocontrol agents against P. comstocki, with the aim of developing a biocontrol programme in France. We carried out systematic DNA-barcoding at each step in the search for a specialist parasitoid. First we characterised the French target populations of P. comstocki. We then identified the parasitoids attacking P. comstocki in France. Finally, we searched for foreign mealybug populations identified a priori as P. comstocki and surveyed their hymenopteran parasitoids. Three mealybug species (P. comstocki, P. viburni and P. cryptus were identified during the survey, together with at least 16 different parasitoid taxa. We selected candidate biological control agent populations for use against P. comstocki in France, from the species Allotropa burrelli (Hymenoptera: Platygastridae and Acerophagus malinus (Hymenoptera: Encyrtidae. The coupling of molecular and morphological characterisation for both pests and natural enemies facilitated the programme development and the rejection of unsuitable or generalist parasitoids.

  19. Seasonal phenology, spatial distribution, and sampling plan for the invasive mealybug Phenacoccus peruvianus (Hemiptera: Pseudococcidae).

    Science.gov (United States)

    Beltrá, A; Garcia-Marí, F; Soto, A

    2013-06-01

    Phlenacoccus peruvianus Granara de Willink (Hemiptera: Pseudococcidae) is an invasive mealybug of Neotropical origin. In recent years it has invaded the Mediterranean Basin causing significant damages in bougainvillea and other ornamental plants. This article examines its phenology, location on the plant and spatial distribution, and presents a sampling plan to determine P. peruvianus population density for the management of this mealybug in southern Europe. Six urban green spaces with bougainvillea plants were periodically surveyed between March 2008 and September 2010 in eastern Spain, sampling bracts, leaves, and twigs. Our results show that P. peruvianus abundance was high in spring and summer, declining to almost undetectable levels in autumn and winter. The mealybugs showed a preference for settling on bracts and there were no significant migrations between plant organs. P. peruvianus showed a highly aggregated distribution on bracts, leaves, and twigs. We recommend abinomial sampling of 200 leaves and an action threshold of 55% infested leaves for integrated pest management purposes on urban landscapes and enumerative sampling for ornamental nursery management and additional biological studies.

  20. Analysis of root-knot nematode and fusarium wilt disease resistance in cotton (Gossypium spp.) using chromosome substitution lines from two alien species

    Science.gov (United States)

    To Identify a new germplasm resource, and to validate chromosomal regions and favorable alleles associated with nematode and fungal disease resistance traits, a series of interspecific cotton (Gossypium spp.) chromosome substitution (CS) lines were used in this study. The CS lines were developed in ...

  1. Density-dependent benefits in ant-hemipteran mutualism? The case of the ghost ant Tapinoma melanocephalum (Hymenoptera: Formicidae and the invasive mealybug Phenacoccus solenopsis (Hemiptera: Pseudococcidae.

    Directory of Open Access Journals (Sweden)

    Aiming Zhou

    Full Text Available Although density-dependent benefits to hemipterans from ant tending have been measured many times, few studies have focused on integrated effects such as interactions between ant tending, natural enemy density, and hemipteran density. In this study, we tested whether the invasive mealybug Phenacoccus solenopsis is affected by tending by ghost ants (Tapinoma melanocephalum, the presence of parasitoids, mealybug density, parasitoid density and interactions among these factors. Our results showed that mealybug colony growth rate and percentage parasitism were significantly affected by ant tending, parasitoid presence, and initial mealybug density separately. However, there were no interactions among the independent factors. There were also no significant interactions between ant tending and parasitoid density on either mealybug colony growth rate or percentage parasitism. Mealybug colony growth rate showed a negative linear relationship with initial mealybug density but a positive linear relationship with the level of ant tending. These results suggest that benefits to mealybugs are density-independent and are affected by ant tending level.

  2. Mealybugs (Hemiptera: Coccomorpha: Pseudococcidae) with oral rim ducts; description of a new genus and species from Turkey, and discussion of their higher classification within the Pseudococcidae.

    Science.gov (United States)

    Kaydan, Mehmet Bora; Szita, Éva

    2017-02-03

    A new monotypic mealybug genus with oral rim ducts, Bromusicoccus Kaydan gen. n. (Hemiptera: Pseudococcidae: Pseudococcinae), is described from Turkey. The higher classification of mealybug genera with oral rim tubular ducts worldwide is discussed and a key is provided to separate them.

  3. Absorption and translocation of 32P through root feeding by root (Wilt) affected coconut palms

    International Nuclear Information System (INIS)

    Beena George, S.; Moossa, P.P.; Sureshkumar, P.

    2017-01-01

    An investigation was carried out during 2015-16 to study the absorption and translocation of 32 P by root (wilt) affected coconut palms through root feeding in the Department of Soil Science and Agricultural Chemistry, College of Horticulture, Vellanikkara. Root (wilt) is one of the major diseases affecting coconut production in India. Etiology of the disease has been examined from several angles and it was found that nutrition imbalance in association with root (wilt) and it remains so even if integrated nutrient management practices are applied to diseased palms. Absorption and translocation of nutrients in three different types of coconut palms (healthy, apparently healthy and diseased palms) were studied using radioactive phosphorusin laterite soil. Ten morphologically uniform palms of same age were selected from each type of palms. Four active young roots were excavated from each palm and 32 P was applied by root feeding and index leaves were radio assayed for 32 P count at 24 hours, 15 and 30 days after application. The results revealed that healthy palms recorded significantly higher count rate(581 to 25158.66 cpm g -1 ) with root feeding compared to diseased palms(263 to 1068.38 cpm g - 1 ). From the present study it was clear that root (wilt) disease cannot be managed by soil application of nutrients because roots of the diseased palms are not able to translocate these nutrients. Since nutrient imbalance was one of the major problems noticed in root (wilt) affected palms, further study is required to find out proper method of nutrient application. (author)

  4. First report of laurel wilt, caused by Raffaelea lauricola , on Sassafras ( Sassafras albidum ) in Arkansas

    Science.gov (United States)

    Rabiu Olatinwo; C. Barton; Stephen Fraedrich; W. Johnson; J. Hwang

    2016-01-01

    Laurel wilt, caused by Raffaelea lauricola T.C. Harrin., Aghayeva & Fraedrich, is a lethal disease that affects members of the laurel family (Lauraceae) including avocado (Persea americana Mill), redbay (Persea borbonia [L.] Spreng., Nees), and sassafras (Sassafras albidum [Nutt.]). The fungus is a symbiont of an exotic ambrosia beetle (Xyleborus glabratus...

  5. First report of laurel wilt, caused by Raffaelea lauricola , on spicebush ( Lindera benzoin ) in South Carolina

    Science.gov (United States)

    S. W. Fraedrich; T. C. Harrington; B. A. McDaniel; G. S. Best

    2016-01-01

    Most members of the laurel family (Lauraceae) indigenous to the United States appear to be highly susceptible to laurel wilt, a disease caused by Raffaelea lauricola T.C. Harr., Aghayeva & Fraedrich, a fungal symbiont of the redbay ambrosia beetle (Xyleborus glabratus Eichhoff) (Fraedrich et al. 2008; Harrington et al. 2008). The beetle and fungus were...

  6. Breeding and genetics of lettuce for resistance against race 2 Verticillium wilt

    Science.gov (United States)

    Verticillium wilt, caused by Verticillium dahliae Kleb., is an economically important disease of lettuce in central coastal California. Most isolates of the pathogen detected in the Salinas Valley belong to race 1 for which complete resistance exists. However, adequate level of resistance is not ava...

  7. Biological Control of Fusarium Wilt of Tomato – A Review | Monda ...

    African Journals Online (AJOL)

    Fusarium wilt of tomato (Lycopersicum esculentum) caused by Fusarium oxysporum f.sp. lycopersici leads to high losses of tomatoes in many countries. Increasing restraints on the use of pesticides encourages adoption of use of alternative strategies of controlling the disease. Alternative strategies include use of biocontrol ...

  8. Aerial remote sensing survey of Fusarium wilt of cotton in New Mexico and Texas

    Science.gov (United States)

    Fusarium wilt of cotton, caused by the fungus Fusarium oxysporum f. sp. vasinfectum (FOV), is a widespread cotton disease, but the more virulent FOV race 4 (FOV4) has recently been identified in the New Mexico-Texas border area near El Paso, Texas. A preliminary aerial remote sensing survey was cond...

  9. Screening of wild and cultivated Capsicum germplasm reveals new sources of Verticillium wilt resistance

    Science.gov (United States)

    Verticillium wilt caused by Verticillium dahliae is an important soilborne disease of pepper (Capsicum species) worldwide. Most commercial pepper cultivars lack resistance to this pathogen. Our objective was to identify resistance to multiple V. dahliae isolates in wild and cultivated Capsicum acces...

  10. Recent advances in the control of oak wilt in the United States

    Science.gov (United States)

    Dan A. Wilson

    2005-01-01

    Oak wilt, caused by Ceratocystis fagacearum (T.W.Bretz) J. Hunt, is probably the most destructive disease of oak trees (Quercus species) in the United States, and is currently causing high morality at epiphytotic proportions in central Texas. The serious potential for damage pro,pted an increase in federal funding within the past...

  11. Biological control of fusarium wilt of tomato by antagonist fungi and ...

    African Journals Online (AJOL)

    Biological control of Fusarium oxysporum f. sp. lycopersici (FOL) causing wilt disease of tomato was studied in vitro as well as under pot conditions. Dual culture technique showed that Aspergillus niger, Penicillium citrinum, Penicillium sp. and Trichoderma harzianum inhibited the radial colony growth of the test pathogen.

  12. Comparison of ambrosia beetle communities in two hosts with laurel wilt: swampbay vs. avocado

    Science.gov (United States)

    The invasive redbay ambrosia beetle, Xyleborus glabratus (Coleoptera: Curculionidae: Scolytinae), is an exotic wood-boring pest first detected in 2002 near Savannah, Georgia. The beetle’s dominant fungal symbiont, Raffaelea lauricola, is the pathogen that causes laurel wilt, a lethal disease of tre...

  13. Vertical distribution and daily flight periodicity of ambrosia beetles associated with laurel wilt affected avocado orchards.

    Science.gov (United States)

    Recently, ambrosia beetles have emerged as significant pests of avocado (Persea americana Mill.; Lauraceae) due to their association with fungal pathogens, in particular, the causal agent of laurel wilt disease, Raffaelea lauricola. The objective of this study was to provide insights into the intera...

  14. Influence of mating disruption on the reproductive biology of the vine mealybug, Planococcus ficus (Hemiptera: Pseudococcidae), under field conditions.

    Science.gov (United States)

    Cocco, Arturo; Muscas, Enrico; Mura, Alessandra; Iodice, Andrea; Savino, Francesco; Lentini, Andrea

    2018-05-08

    Although mating disruption is increasingly being used to control the worldwide grapevine pest vine mealybug, Planococcus ficus (Signoret) (Hemiptera: Pseudococcidae), its mode of action remains unclear. A three-year field experiment was carried out to investigate the effects of mating disruption on the development and reproduction of the vine mealybug. The influence of mating disruption applied over consecutive years on the pest population density was also evaluated. The percentage of ovipositing females was significantly reduced in disrupted plots by 18.8-66.2%, depending on the year. The absence of ovipositing females in disrupted plots in the autumn of the second and third year indicates the effectiveness of mating disruption throughout the whole growing season. Mating disruption consistently prolonged the pre-oviposition period in all years by up to 12.5 days. Our findings provide new insights into the mechanisms underlying the pheromone-based control of the vine mealybug and indicate that the reduction of the pest population density is due to both a decrease and delay in female mating. In addition, the population density of vine mealybugs under mating disruption decreased over years, indicating that consecutive applications of this control strategy would significantly increase the effectiveness of controlling the vine mealybug by mating disruption. This article is protected by copyright. All rights reserved.

  15. Biological Control of Bacterial Wilt in South East Asia

    Directory of Open Access Journals (Sweden)

    Triwidodo Arwiyanto

    2014-12-01

    Full Text Available Bacterial wilt disease caused by Ralstonia solanacearum destroys many crops of different plant families in South East Asia despite many researches about the disease, and the availability of developed control method in other parts of the world. There is no chemical available for the bacterial wilt pathogen and biological control is then chosen as an alternative to save the crops. Most of the biological control studies were based on antagonism between biological control agent and the pathogen. The biological control agents were intended to reduce the initial inoculum of the pathogen. The effort to minimize the initial inoculum of the pathogen by baiting with the use of hypersensitive host-plant was only reliable when conducted in the greenhouse experiments. Various microorganisms have been searched as possible biological control agents, for instance avirulent form of the pathogen, soil or rhizosphere bacteria (Bacillus spp. and fluorescent pseudomonads, actinomycetes (Streptomyces spp., yeast (Pichia uillermondii, Candida ethanolica, and a consortium of microorganisms known as effective microorganisms (EM. None of these biological control agents has been used in field application and they need further investigation in order to effectively control bacterial wilt. Opportunities and challenges in developing biological control to combat bacterial wilt are discussed in the paper. Penyakit layu bakteri yang disebabkan oleh Ralstonia solanacearum menghancurkan banyak tanaman dalam famili yang berbeda di Asia Tenggara meskipun telah banyak penelitian tentang metode pengendaliannya. Penyakit ini sulit dikendalikan karena banyaknya variabilitas patogen dan belum tersedianya sumber ketahanan yang mapan. Di samping itu, sampai saat ini belum ada bahan kimia yang tersedia untuk patogen layu bakteri ini sehingga pengendalian biologi kemudian dipilih sebagai cara alternatif untuk menyelamatkan tanaman. Sebagian besar penelitian pengendalian biologi didasarkan

  16. Ocorrência de cochonilhas em espinheira-santa (Maytenus ilicifolia Mart. ex Reissek Occurrence of mealybugs in "espinheira-santa" (Maytenus ilicifolia Mart. ex Reissek

    Directory of Open Access Journals (Sweden)

    J.M. Vitória

    2013-01-01

    Full Text Available Maytenus ilicifolia é uma espécie medicinal nativa do Brasil que vem sendo cultivada para atender a crescente demanda do mercado. Os fatores que interferem na produção, tal como a incidência de pragas e doenças, devem ser estudados para garantir o incremento na produtividade. O objetivo deste trabalho foi registrar a ocorrência e a identificação de cochonilhas associadas a 15 acessos de espinheira-santa (Maytenus ilicifolia do Banco Ativo de Germoplasma da Embrapa Clima Temperado e do Instituto Federal Sul-rio-grandense. Foi registrada a quantidade de plantas infestadas em cada acesso e identificado, em laboratório, as espécies de cochonilhas infestantes. O número de plantas infestadas variou entre os acessos. Foram identificadas as cochonilhas Ceroplastes sp. e Saissetia oleae, família Coccidae. Dos 10 acessos infestados, 23 (11,3% plantas apresentaram infestação com Ceroplastes sp. e, apenas uma (0,5%, com Saissetia oleae. O acesso 133 mostrou a maior incidência de Ceroplastes sp. (33,3%, seguido do acesso 130 (25,0%. O acesso 123 foi o que apresentou menor quantidade de plantas infestadas (4,8%. Saissetia oleae ocorreu em apenas uma planta, pertencente ao acesso 136 (5,6%.Maytenus ilicifolia is a medicinal species native to Brazil which has been cultivated to meet the growing market demand. Factors that interfere with the production, such as the incidence of pests and diseases, should be studied to ensure increased productivity. The aim of this study was to record the occurrence and the identification of mealybugs associated with 15 "espinheira-santa" (Maytenus ilicifolia accessions from the Active Germplasm Bank of "Embrapa Clima Temperado" and "Instituto Federal Sul-rio-grandense". The quantity of infested plants in each accession was recorded and the species of infested mealybugs were identified in the laboratory. The number of infested plants varied among accessions. The identified mealybugs were Ceroplastes sp. and

  17. A model for multiseasonal spread of verticillium wilt of lettuce.

    Science.gov (United States)

    Wu, B M; Subbarao, K V

    2014-09-01

    Verticillium wilt, caused by Verticillium dahliae, is a destructive disease in lettuce, and the pathogen is seedborne. Even though maximum seed infestation rates of lettuce seed lots, it is necessary to establish acceptable contamination thresholds to prevent introduction and establishment of the pathogen in lettuce production fields. However, introduction of inoculum into lettuce fields for experimental purposes to determine its long term effects is undesirable. Therefore, we constructed a simulation model to study the spread of Verticillium wilt following pathogen introduction from seed. The model consists of four components: the first for simulating infection of host plants, the second for simulating reproduction of microsclerotia on diseased plants, the third for simulating the survival of microsclerotia, and the fourth for simulating the dispersal of microsclerotia. The simulation results demonstrated that the inoculum density-disease incidence curve parameters and the dispersal gradients affect disease spread in the field. Although a steep dispersal gradient facilitated the establishment of the disease in a new field with a low inoculum density, a long-tail gradient allowed microsclerotia to be dispersed over greater distances, promoting the disease spread in fields with high inoculum density. The simulation results also revealed the importance of avoiding successive lettuce crops in the same field, reducing survival rate of microsclerotia between crops, and the need for breeding resistance against V. dahliae in lettuce cultivars to lower the number of microsclerotia formed on each diseased plant. The simulation results, however, suggested that, even with a low seed infestation rate, the pathogen would eventually become established if susceptible lettuce cultivars were grown consecutively in the same field for many years. A threshold for seed infestation can be established only when two of the three drivers of the disease-(i) low microsclerotia production per

  18. Continous application of bioorganic fertilizer induced resilient culturable bacteria community associated with banana Fusarium wilt suppression

    Science.gov (United States)

    Fu, Lin; Ruan, Yunze; Tao, Chengyuan; Li, Rong; Shen, Qirong

    2016-06-01

    Fusarium wilt of banana always drives farmers to find new land for banana cultivation due to the comeback of the disease after a few cropping years. A novel idea for solving this problem is the continuous application of bioorganic fertilizer (BIO), which should be practiced from the beginning of banana planting. In this study, BIO was applied in newly reclaimed fields to pre-control banana Fusarium wilt and the culturable rhizobacteria community were evaluated using Biolog Ecoplates and culture-dependent denaturing gradient gel electrophoresis (CD-DGGE). The results showed that BIO application significantly reduced disease incidences and increased crop yields, respectivly. And the stabilized general bacterial metabolic potential, especially for the utilization of carbohydrates, carboxylic acids and phenolic compounds, was induced by BIO application. DGGE profiles demonstrated that resilient community structure of culturable rhizobacteria with higher richness and diversity were observed in BIO treated soils. Morever, enriched culturable bacteria affiliated with Firmicutes, Gammaproteobacteria and Actinobacteria were also detected. In total, continuous application of BIO effectively suppressed Fusarium wilt disease by stabilizing culturable bacterial metabolic potential and community structure. This study revealed a new method to control Fusarium wilt of banana for long term banana cultivation.

  19. Methylation-sensitive amplified polymorphism analysis of Verticillium wilt-stressed cotton (Gossypium).

    Science.gov (United States)

    Wang, W; Zhang, M; Chen, H D; Cai, X X; Xu, M L; Lei, K Y; Niu, J H; Deng, L; Liu, J; Ge, Z J; Yu, S X; Wang, B H

    2016-10-06

    In this study, a methylation-sensitive amplification polymorphism analysis system was used to analyze DNA methylation level in three cotton accessions. Two disease-sensitive near-isogenic lines, PD94042 and IL41, and one disease-resistant Gossypium mustelinum accession were exposed to Verticillium wilt, to investigate molecular disease resistance mechanisms in cotton. We observed multiple different DNA methylation types across the three accessions following Verticillium wilt exposure. These included hypomethylation, hypermethylation, and other patterns. In general, the global DNA methylation level was significantly increased in the disease-resistant accession G. mustelinum following disease exposure. In contrast, there was no significant difference in the disease-sensitive accession PD94042, and a significant decrease was observed in IL41. Our results suggest that disease-resistant cotton might employ a mechanism to increase methylation level in response to disease stress. The differing methylation patterns, together with the increase in global DNA methylation level, might play important roles in tolerance to Verticillium wilt in cotton. Through cloning and analysis of differently methylated DNA sequences, we were also able to identify several genes that may contribute to disease resistance in cotton. Our results revealed the effect of DNA methylation on cotton disease resistance, and also identified genes that played important roles, which may shed light on the future cotton disease-resistant molecular breeding.

  20. Biological control agent against verticillium wilt

    CSIR Research Space (South Africa)

    Gumede, WHN

    2006-04-01

    Full Text Available Verticillium wilt Presented at the 14th Biennial congress of the South African Society for Microbiology WHN Gumede CSIR Biosciences 11-04-06 Slide 2 © CSIR 2006 www.csir.co.za INTRODUCTION • Historical background • Application...

  1. Potency of Six Isolates of Biocontrol Agents Endophytic Trichoderma Against Fusarium Wilt on Banana

    OpenAIRE

    Taribuka, J; Wibowo, A; Widyastuti, S M; Sumardiyono, C

    2017-01-01

    Fusarium wilt caused by F. oxysporum f.sp. cubense is one of very damaging banana plant diseases which can cause plant death. Disease control using intensive chemical fungicides will have negative impacts on the environment and humans. Endophytic Trichoderma is one of the biological control agents which can reduce the amount of inoculum of pathogens, so it can reduce disease intensity. The objectives of this study was to assess the ability of endophytic Trichoderma in inducing plant resistanc...

  2. Management of vascular wilt of lentil through host plant resistance, biological control agents and chemicals

    International Nuclear Information System (INIS)

    Rafique, K.; Rauf, C.A.; Naz, F.

    2016-01-01

    The management of devastating lentil (Lens culinaris Medik.) wilt disease was investigated through evaluation of host plant resistance, biological control agents and seed treatment with different fungicides against a known most aggressive isolate i.e. FWL12 (KP297995) of Fusarium oxysporum f. sp. lentis. The In vitro screening of germplasm (23 advanced lines and cultivars) for host resistance by root dip method revealed five cultivars viz. Markaz-09, Masoor-86, Masoor-2006, Punjab Masoor-00518 and Punjab Masoor-09 resistant with 20 to 46.67% incidence, 4.44 to 12.95% severity index and 9.60 to 24.94% yield reduction compared with highly susceptible (100% incidence) local lentil line (NARC-08-1). The later line was treated with Trichoderma species as antagonists in pot experiment by drenching. The bio-control treatment revealed maximum positive effect of T. harzianum (26.7% incidence, 8.9% severity index and 16.27% yield reduction), followed by T. viride (66.7% incidence, 17.8% severity index and 31.13% yield reduction). On inoculated untreated control, the fungus produced the characteristic wilt symptoms and significantly caused increased severity index, incidence and decreased 100% yield. In vitro evaluation of four fungicides at five concentrations (10, 20, 30, 50 and 100 ppm) revealed maximum inhibition of the test fungus with benomyl (85.9%), followed by thiophanate methyl (81.2%). Determination of the efficacy of two best fungicides viz. benomyl and thiophanate methyl in reducing wilt infection through In vivo seed treatment of NARC-08-1 in previously inoculated potting mixture revealed 100% seed germination and suppressed wilt disease, the most effective being benomyl with 6.7% incidence, 1.5% wilt severity and 17.16% yield reduction compared to the control. The study concluded that the genetic diversity already present in lentil cultivars is an important source, which could be exploited for breeding wilt resistant lentil genotypes. Moreover, being seed and

  3. Identification of molecular markers associated with Verticillium wilt resistance in alfalfa (Medicago sativa L.) using high-resolution melting.

    Science.gov (United States)

    Zhang, Tiejun; Yu, Long-Xi; McCord, Per; Miller, David; Bhamidimarri, Suresh; Johnson, David; Monteros, Maria J; Ho, Julie; Reisen, Peter; Samac, Deborah A

    2014-01-01

    Verticillium wilt, caused by the soilborne fungus, Verticillium alfalfae, is one of the most serious diseases of alfalfa (Medicago sativa L.) worldwide. To identify loci associated with resistance to Verticillium wilt, a bulk segregant analysis was conducted in susceptible or resistant pools constructed from 13 synthetic alfalfa populations, followed by association mapping in two F1 populations consisted of 352 individuals. Simple sequence repeat (SSR) and single nucleotide polymorphism (SNP) markers were used for genotyping. Phenotyping was done by manual inoculation of the pathogen to replicated cloned plants of each individual and disease severity was scored using a standard scale. Marker-trait association was analyzed by TASSEL. Seventeen SNP markers significantly associated with Verticillium wilt resistance were identified and they were located on chromosomes 1, 2, 4, 7 and 8. SNP markers identified on chromosomes 2, 4 and 7 co-locate with regions of Verticillium wilt resistance loci reported in M. truncatula. Additional markers identified on chromosomes 1 and 8 located the regions where no Verticillium resistance locus has been reported. This study highlights the value of SNP genotyping by high resolution melting to identify the disease resistance loci in tetraploid alfalfa. With further validation, the markers identified in this study could be used for improving resistance to Verticillium wilt in alfalfa breeding programs.

  4. Identification of molecular markers associated with Verticillium wilt resistance in alfalfa (Medicago sativa L. using high-resolution melting.

    Directory of Open Access Journals (Sweden)

    Tiejun Zhang

    Full Text Available Verticillium wilt, caused by the soilborne fungus, Verticillium alfalfae, is one of the most serious diseases of alfalfa (Medicago sativa L. worldwide. To identify loci associated with resistance to Verticillium wilt, a bulk segregant analysis was conducted in susceptible or resistant pools constructed from 13 synthetic alfalfa populations, followed by association mapping in two F1 populations consisted of 352 individuals. Simple sequence repeat (SSR and single nucleotide polymorphism (SNP markers were used for genotyping. Phenotyping was done by manual inoculation of the pathogen to replicated cloned plants of each individual and disease severity was scored using a standard scale. Marker-trait association was analyzed by TASSEL. Seventeen SNP markers significantly associated with Verticillium wilt resistance were identified and they were located on chromosomes 1, 2, 4, 7 and 8. SNP markers identified on chromosomes 2, 4 and 7 co-locate with regions of Verticillium wilt resistance loci reported in M. truncatula. Additional markers identified on chromosomes 1 and 8 located the regions where no Verticillium resistance locus has been reported. This study highlights the value of SNP genotyping by high resolution melting to identify the disease resistance loci in tetraploid alfalfa. With further validation, the markers identified in this study could be used for improving resistance to Verticillium wilt in alfalfa breeding programs.

  5. Fusarium Wilt Caused by Fusarium oxysporum on Passionfruit in Korea

    Directory of Open Access Journals (Sweden)

    Jae-Ho Joa

    2018-03-01

    Full Text Available From 2014 to 2016, Fusarium wilt disease was found on fassionfruit in Iksan and Jeju, Korea. Symptoms included wilting of foliage, drying and withering of leaves, and stunting of the plants. The infected plants eventually died during growth. Colonies on potato dextrose agar were pinkish white, and felted with cottony and aerial mycelia with 35 mm after one week. Macroconidia were falcate to almost straight, thin-walled and usually 2-3 septate. Microconidia were usually formed on monophialides of the hyphae and were hyaline, smooth, oval to ellipsoidal, aseptate or medianly 1-septate, very occasionally 2-septate, slightly constricted at the septa, 3-12 x 2.5-6 μm. On the basis of the morphological characteristics and phylogenetic analyses of two molecular markers, internal transcribed spacer rDNA and translation elongation factor 1α, the fungus was identified as Fusarium oxysporum. Pathogenicity of a representative isolate was proved by artificial inoculation, fulfilling Koch's postulates. To our knowledge, this is the first report on the occurrence of F. oxysporum on fassionfruit in Korea.

  6. Biology of Pink Hibiscus MealybugMaconellicoccushirsutus (Green on Chinese Hibiscus Shrubs in Khuzestan Province

    Directory of Open Access Journals (Sweden)

    M. Sadat Alizadeh

    2017-12-01

    Full Text Available Introduction: The pink hibiscus mealybug, Maconellicoccushirsutus (Green (Hem.:Pseudococcidae is one of the serious economic pests of agricultural crops in tropical and subtropical regions.This pesthas spread through Asia, Africa, America and Australia, and infests more than 330 host plants which some of them have the important role in theeconomy. This sap-feeding insect secrets honeydew which provides suitablemedium for black sooty moldgrowth. It also releases a toxin during feeding, which results in severe stunting, decline, and deformation of twigs. It has recorded as a pest on different host plants in southern Iranian provinces since the 1990s.In Khuzestan province, it was first observed on Chinese hibiscus shrubs in urban landscapes of Ahvaz in February 2009. The evergreen hibiscus shrub is very common in the urban landscape of warmcities of Khuzestan province. The severity of mealybug damage to hibiscus shrubs causedto becut off in some regions. As there is no data on the biology of M. hirsutus in Iran,in the present study, the biologyof this pestwas investigatedat different temperatures in laboratory conditions as well as its population fluctuations on Chinese hibiscus shrubs in urban landscapes of Ahvaz. Materials and methods: Biology of the pest species was evaluated at five laboratory constant temperatures 15, 20, 25, 30and 35±2°C (65±5% RH and a photoperiod of L: D 14:10 h on Chinese hibiscus leaves in plastic boxes (8×6×2 cm. Number ofM. hirsutusgenerations was also studied in clip cages on hibiscus shrubs in Ahvaz urban landscapes within a year. Population fluctuations of the insect were also investigated on those shrubs in two different regions of Ahvaz for 16 months. For this purpose, random sampling was done on five shrubs in each region bi-weekly. Eight twigs, 5 cm in length, were cut from the upper and lower halves of each shrub quadrant and a number of all mealybug developmental stages per twig were counted and recorded

  7. Nitrate Increased Cucumber Tolerance to Fusarium Wilt by Regulating Fungal Toxin Production and Distribution

    Directory of Open Access Journals (Sweden)

    Jinyan Zhou

    2017-03-01

    Full Text Available Cucumber Fusarium wilt, induced by Fusarium oxysporum f. sp. cucumerinum (FOC, causes severe losses in cucumber yield and quality. Nitrogen (N, as the most important mineral nutrient for plants, plays a critical role in plant–pathogen interactions. Hydroponic assays were conducted to investigate the effects of different N forms (NH4+ vs. NO3‒ and supply levels (low, 1 mM; high, 5 mM on cucumber Fusarium wilt. The NO3‒-fed cucumber plants were more tolerant to Fusarium wilt compared with NH4+-fed plants, and accompanied by lower leaf temperature after FOC infection. The disease index decreased as the NO3‒ supply increased but increased with the NH4+ level supplied. Although the FOC grew better under high NO3− in vitro, FOC colonization and fusaric acid (FA production decreased in cucumber plants under high NO3− supply, associated with lower leaf membrane injury. There was a positive correlation between the FA content and the FOC number or relative membrane injury. After the exogenous application of FA, less FA accumulated in the leaves under NO3− feeding, accompanied with a lower leaf membrane injury. In conclusion, higher NO3− supply protected cucumber plants against Fusarium wilt by suppressing FOC colonization and FA production in plants, and increasing the plant tolerance to FA.

  8. Nitrate Increased Cucumber Tolerance to Fusarium Wilt by Regulating Fungal Toxin Production and Distribution.

    Science.gov (United States)

    Zhou, Jinyan; Wang, Min; Sun, Yuming; Gu, Zechen; Wang, Ruirui; Saydin, Asanjan; Shen, Qirong; Guo, Shiwei

    2017-03-11

    Cucumber Fusarium wilt, induced by Fusarium oxysporum f. sp. cucumerinum (FOC), causes severe losses in cucumber yield and quality. Nitrogen (N), as the most important mineral nutrient for plants, plays a critical role in plant-pathogen interactions. Hydroponic assays were conducted to investigate the effects of different N forms (NH₄⁺ vs. NO₃ ‒ ) and supply levels (low, 1 mM; high, 5 mM) on cucumber Fusarium wilt. The NO₃ ‒ -fed cucumber plants were more tolerant to Fusarium wilt compared with NH₄⁺-fed plants, and accompanied by lower leaf temperature after FOC infection. The disease index decreased as the NO₃ ‒ supply increased but increased with the NH₄⁺ level supplied. Although the FOC grew better under high NO₃ - in vitro, FOC colonization and fusaric acid (FA) production decreased in cucumber plants under high NO₃ - supply, associated with lower leaf membrane injury. There was a positive correlation between the FA content and the FOC number or relative membrane injury. After the exogenous application of FA, less FA accumulated in the leaves under NO₃ - feeding, accompanied with a lower leaf membrane injury. In conclusion, higher NO₃ - supply protected cucumber plants against Fusarium wilt by suppressing FOC colonization and FA production in plants, and increasing the plant tolerance to FA.

  9. Effect of Nutrition Solution pH and Electrical Conductivity on Fusarium Wilt on Strawberry Plants in Hydroponic Culture

    Directory of Open Access Journals (Sweden)

    Myeong Hyeon Nam

    2018-03-01

    Full Text Available Fusarium wilt on strawberry plants caused by Fusarium oxysporum f. sp. fragariae (Fof is a major disease in Korea. The prevalence of this disease is increasing, especially in hydroponic cultivation in strawberry field. This study assessed the effect of nutrition solution pH and electrical conductivity (EC on Fusarium wilt in vitro and in field trials. pH levels of 5.0, 5.5, 6.0, 6.5, 7.0, and 7.5 were assayed in vitro and in field trials. EC levels at 0, 0.5, 0.8, 1.0, and 1.5 dS∙m⁻¹ were assayed in field trials. Mycelial growth of Fof increased with increasing pH and was highest at 25°C pH 7 and lowest at 20°C, pH 5.0 in vitro. The incidence of Fusarium wilt was lowest in the pH 6.5 treatment and highest in the pH 5 treatment in field trials. At higher pH levels, the EC decreased in the drain solution and the potassium content of strawberry leaves increased. In the EC assay, the severity of Fusarium wilt and nitrogen content of leaves increased as the EC increased. These results indicate that Fusarium wilt is related to pH and EC in hydroponic culture of strawberry plants.

  10. Aggressiveness of Cephalosporium maydis causing late wilt of maize in Spain

    OpenAIRE

    García-Carneros, Ana B.; Girón, I.; Molinero-Ruiz, Leire

    2012-01-01

    Late wilt of maize, caused by the vascular and soilborne pathogen Cephalosporium maydis, was identified in the Iberian Peninsula in 2008. During the last years the incidence and economical impact of the disease has importantly increased both in Portugal and Spain. Varieties of maize displaying tolerance to the pathogen are available, but the effectiveness can be dependent on the virulence of the fungus (i.e. ability to cause disease on a specific genotype). On the other hand, strains of crop ...

  11. Host preference of the vector beetle, host resistance, and expanding patterns of Japanese oak wilt in a stand

    Science.gov (United States)

    Kazuyoshi Futai; Hiroaki Kiku; Hong-ye Qi; Hagus Tarn; Yuko Takeuchi; Michimasa. Yamasaki

    2012-01-01

    Since the early 1980s, an epidemic forest disease, Japanese Oak Wilt (JOW), has been spreading from coastal areas along the Sea of Japan to the interior of Honshu island and has been devastating huge areas of forests by killing an enormous number of oak trees in urban fringe mountains, gardens, and parks. The disease is caused by a fungus, Raffaelea...

  12. Wheat Intercropping Enhances the Resistance of Watermelon to Fusarium Wilt

    OpenAIRE

    Huifang Lv; Huifang Lv; Haishun Cao; Muhammad A. Nawaz; Hamza Sohail; Yuan Huang; Fei Cheng; Qiusheng Kong; Zhilong Bie

    2018-01-01

    A fungus Fusarium oxysporum F. sp. niveum (FON) is the causal organism of Fusarium wilt in watermelon. In this study, we evaluated the effect of wheat intercropping on the Fusarium wilt of watermelon. Our results showed that wheat intercropping decreases the incidence of Fusarium wilt of watermelon, likely due to the secretion of coumaric acid from the roots of wheat that dramatically inhibits FON spore germination, sporulation, and growth. The secretion of p-hydroxybenzoic acid, ferulic acid...

  13. Field evaluation of two systemic neonicotinoid insecticides against pink hibiscus mealybug (Maconellicoccus hirsutus (Green))on mulberry trees

    Science.gov (United States)

    Infestations of the pink hibiscus mealybug, Maconellicoccus hirsutus (Green), in ornamental trees were already in an advanced state at the time of its discovery in the Imperial Valley of California (USA) in August 1999. Concern about the spread of M. hirsutus beyond the Imperial Valley led to the p...

  14. Efficacy of Isaria fumosorosea Wize (Hypocreales: Cordycipitaceae) on the leaf phylloplane over time for controlling Madeira mealybug nymphs preshipping

    Science.gov (United States)

    The efficacy of Isaria fumosorosea (= PFR 97®) on the leaf phylloplane over time for controlling Madeira mealybug nymphs before shipping plant products was assessed under laboratory conditions. Hibiscus leaves were dipped into beakers filled with 0, 1, 2, 4, 8, and 10 g of PFR 97® / L of water and t...

  15. Population growth and within-plant distribution of the striped mealybug Ferrisia virgata (Cockerell (Hemiptera, Pseudococcidae on cotton

    Directory of Open Access Journals (Sweden)

    Martin D. Oliveira

    2014-03-01

    Full Text Available Population growth and within-plant distribution of the striped mealybug Ferrisia virgata (Cockerell (Hemiptera, Pseudococcidae on cotton. The striped mealybug, Ferrisia virgata (Cockerell (Hemiptera, Pseudococcidae, is a widely distributed and polyphagous pest species, which naturally occurs on cotton plants in Brazil. This study evaluated the establishment and population growth as well as the within-plant distribution of F. virgata on four cotton cultivars: CNPA 7H (white fibers, BRS Verde, BRS Safira, and BRS Rubi (colored fibers. The experiment was conducted in a complete randomized design with four treatments (cultivars and 18 replications of each. Thus, cotton plants of each cultivar were infested with 100 newly hatched nymphs of F. virgata. The number of adult female mealybugs and the total number of mealybugs per plant were quantified, respectively, at 25 and 50 days after infestation. The developmental and pre-reproductive periods were also determined. Furthermore, we verified the distribution of F. virgata on the plant parts at 25 and 50 days after infestation. Ferrisia virgata showed similar growth of 412-fold in the four cotton cultivars studied. Also, the nymphs were spread on infested leaves; the secondgeneration nymphs were spread and established in all plant parts. Our results characterize F. virgata as having much potential as an important cotton pest in Brazil.

  16. Biotransfer of Cd along a soil-plant- mealybug-ladybird food chain: A comparison with host plants.

    Science.gov (United States)

    Wang, Xingmin; Zhang, Can; Qiu, Baoli; Ashraf, Umair; Azad, Rashid; Wu, Jianhui; Ali, Shaukat

    2017-02-01

    Agro-ecosystem contamination by the heavy metals present in different agricultural products is a serious challenge faced by the living organisms. This study explains the cadmium (Cd) transfer from soils contaminated with different cadmium concentrations through a plant (eggplant and tomato) - mealybug (Dysmicoccus neobrevipes) - predator (Cryptolaemus-montrouzieri) food chain. The soils were amended with Cd at the rates of 0, 12.5, 25 and 50 mg/kg (w/w). Our findings showed that considerably higher Cd transfer through tomato plant. Cadmium was biomagnified during soil-root transfer while bio-minimization of Cd was observed for shoot-mealybug - ladybird transfer. Our results further showed sequestration of Cd during the metamorphosis of ladybird beetle whilst transfer of Cd through soil-plant-mealybug-ladybird multi-trophic food chain increased in a dose dependent manner. Our results emphasize the need of further studies to elaborate possible mechanisms of Cd bio-minimization by plants, mealybugs and ladybirds observed during this study. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. Effects Of Irradiation On Mealybug Dysmicoccus neobrevipes (Hemiptera: Pseudococcidae) Infesting On Dragon Fruits

    International Nuclear Information System (INIS)

    Doan Thi The; Nguyen Thuy Khanh; Vo Kim Lang; Cao Van Chung; Tran Thien An; Nguyen Hoang Hanh Thi

    2011-01-01

    Since 2008 APHIS/USDA approved to import dragon fruit into the United States from Vietnam if fruits are treated with the minimum absorbed dose of 400 Gy to control fruit flies and mealybugs. However, a lower dose could be accepted if released data is enough to demonstrate that it is efficient to inhibit the development and stop the reproduction of adult females for three species of mealybugs (Order: Hemiptera; Family: Pseudococcidae) infesting on dragon fruit. Four development stages including 1 st , 2 nd , 3 rd instars and adult of Dymicoccus neobrevipes by isolating and rearing in the laboratory conditions were irradiated in Co-60 source gamma with dosages of 100, 200, 300 and 400 Gy. The main purposes of the study are to find the most tolerant stage and to determine the most optimal dose to control D. neobrevipes. The initial obtained results showed that the adult stage is the most radiotolerant and the dose of 200 Gy could be an effective dose to inhibit development and to control reproduction of D. neobrevipes. (author)

  18. Effects of gamma irradiation on different stages of mealybug Dysmicoccus neobrevipes (Hemiptera: Pseudococcidae)

    International Nuclear Information System (INIS)

    The, Doan Thi; Khanh, Nguyen Thuy; Lang, Vo Thi Kim; Van Chung, Cao; An, Tran Thi Thien; Thi, Nguyen Hoang Hanh

    2012-01-01

    Utilization of phytosanitary irradiation as a potential treatment to disinfest agricultural commodities in trade has expanded rapidly in the recent years. Cobalt-60 gamma ray target doses of 100, 150, 200 and 250 Gy were used to irradiate immatures and adults of Dysmicoccus neobrevipes (Beardsley) (Hemiptera: Pseudococcidae) infesting dragon fruits to find the most tolerant stage and the most optimal dose range for quarantine treatment. In general, irradiation affected significantly all life stages of D. neobrevipes mortality and adult reproduction. The pattern of tolerance to irradiation in D. neobrevipes was 1st instars<2nd instars<3rd instars< adults, in which the adult is the most tolerant stage. Based on obtained results after 21 days of irradiation, predicted doses for 100% mortality of each different development stage in the above mentioned pattern were 224.6, 241.3, 330.9 and 581.5 Gy, respectively. No survived female adult produced offspring at 200 and 250 Gy. Dose range between 200 and 250 Gy could be efficient to prevent the reproduction of this mealybug. - Highlights: → Gamma Co-60 irradiation as a potential phytosanitary for quarantine treatments. → Reproduction ability of D. neobrevipes has been efficiently inhibited at low dose. → Pattern of tolerance to irradiation was 1st<2nd<3rd instars< adults. → Doses from 200 to 250 Gy could be efficient to prevent the reproduction of mealybug.

  19. Effects of gamma irradiation on different stages of mealybug Dysmicoccus neobrevipes (Hemiptera: Pseudococcidae)

    Energy Technology Data Exchange (ETDEWEB)

    The, Doan Thi, E-mail: doanthithe@yahoo.com [Research and Development Center for Radiation Technology, Vietnam Atomic Energy Institute, 202A Street 11, Linh Xuan Ward, Thu Duc District, Ho Chi Minh City (Viet Nam); Khanh, Nguyen Thuy; Lang, Vo Thi Kim; Van Chung, Cao [Research and Development Center for Radiation Technology, Vietnam Atomic Energy Institute, 202A Street 11, Linh Xuan Ward, Thu Duc District, Ho Chi Minh City (Viet Nam); An, Tran Thi Thien; Thi, Nguyen Hoang Hanh [Agriculture and Forestry University, Linh Trung Ward, Thu Duc District, Ho Chi Minh City (Viet Nam)

    2012-01-15

    Utilization of phytosanitary irradiation as a potential treatment to disinfest agricultural commodities in trade has expanded rapidly in the recent years. Cobalt-60 gamma ray target doses of 100, 150, 200 and 250 Gy were used to irradiate immatures and adults of Dysmicoccus neobrevipes (Beardsley) (Hemiptera: Pseudococcidae) infesting dragon fruits to find the most tolerant stage and the most optimal dose range for quarantine treatment. In general, irradiation affected significantly all life stages of D. neobrevipes mortality and adult reproduction. The pattern of tolerance to irradiation in D. neobrevipes was 1st instars<2nd instars<3rd instarsmealybug. - Highlights: > Gamma Co-60 irradiation as a potential phytosanitary for quarantine treatments. > Reproduction ability of D. neobrevipes has been efficiently inhibited at low dose. > Pattern of tolerance to irradiation was 1st<2nd<3rd instars Doses from 200 to 250 Gy could be efficient to prevent the reproduction of mealybug.

  20. Suppression of jasmonic acid-dependent defense in cotton plant by the mealybug Phenacoccus solenopsis.

    Directory of Open Access Journals (Sweden)

    Pengjun Zhang

    Full Text Available The solenopsis mealybug, Phenacoccus solenopsis, has been recently recognized as an aggressively invasive pest in China, and is now becoming a serious threat to the cotton industry in the country. Thus, it is necessary to investigate the molecular mechanisms employed by cotton for defending against P. solenopsis before the pest populations reach epidemic levels. Here, we examined the effects of exogenous jasmonic acid (JA, salicylic acid (SA, and herbivory treatments on feeding behavior and on development of female P. solenopsis. Further, we compared the volatile emissions of cotton plants upon JA, SA, and herbivory treatments, as well as the time-related changes in gossypol production and defense-related genes. Female adult P. solenopsis were repelled by leaves from JA-treated plant, but were not repelled by leaves from SA-treated plants. In contrast, females were attracted by leaves from plants pre-infested by P. solenopsis. The diverse feeding responses by P. solenopsis were due to the difference in volatile emission of plants from different treatments. Furthermore, we show that JA-treated plants slowed P. solenopsis development, but plants pre-infested by P. solenopsis accelerated its development. We also show that P. solenopsis feeding inhibited the JA-regulated gossypol production, and prevented the induction of JA-related genes. We conclude that P. solenopsis is able to prevent the activation of JA-dependent defenses associated with basal resistance to mealybugs.

  1. Assessing the Cost of an Invasive Forest Pathogen: A Case Study with Oak Wilt

    Science.gov (United States)

    Haight, Robert G.; Homans, Frances R.; Horie, Tetsuya; Mehta, Shefali V.; Smith, David J.; Venette, Robert C.

    2011-03-01

    Economic assessment of damage caused by invasive alien species provides useful information to consider when determining whether management programs should be established, modified, or discontinued. We estimate the baseline economic damage from an invasive alien pathogen, Ceratocystis fagacearum, a fungus that causes oak wilt, which is a significant disease of oaks ( Quercus spp.) in the central United States. We focus on Anoka County, Minnesota, a 1,156 km2 mostly urban county in the Minneapolis-Saint Paul metropolitan region. We develop a landscape-level model of oak wilt spread that accounts for underground and overland pathogen transmission. We predict the economic damage of tree mortality from oak wilt spread in the absence of management during the period 2007-2016. Our metric of economic damage is removal cost, which is one component of the total economic loss from tree mortality. We estimate that Anoka County has 5.92 million oak trees and 885 active oak wilt pockets covering 5.47 km2 in 2007. The likelihood that landowners remove infected oaks varies by land use and ranges from 86% on developed land to 57% on forest land. Over the next decade, depending on the rates of oak wilt pocket establishment and expansion, 76-266 thousand trees will be infected with discounted removal cost of 18-60 million. Although our predictions of removal costs are substantial, they are lower bounds on the total economic loss from tree mortality because we do not estimate economic losses from reduced services and increased hazards. Our predictions suggest that there are significant economic benefits, in terms of damage reduction, from preventing new pocket establishment or slowing the radial growth of existing pockets.

  2. Using a kairomone-based attracting system to enhance biological control of mealybugs (Hemiptera: Pseudococcidae by Anagyrus sp. near pseudococci (Hymenoptera: Encyrtidae in Sicilian vineyards

    Directory of Open Access Journals (Sweden)

    Ramzi Mansour

    2010-11-01

    Full Text Available The “potato trap” technique was applied for the fi rst time in Italian (Sicily vineyards in an attempt to assess: a the impact of the kairomonal activity of the vine mealybug sex pheromone (S-(+-lavandulyl senecioate (LS on the parasitism of mealybugs by the encyrtid Anagyrus sp. near pseudococci, b the influence of two commonly used insecticides on the parasitization activity of A. sp. near pseudococci towards mealybugs, and c the efficiency of the release of A. sp. near pseudococci in enhancing parasitism rates of mealybugs. The number of captured A. sp. near pseudococci females in LS baited traps was significantly higher than that in unbaited traps. The minimal number of days for the first parasitoid emergence in LS baited traps was almost 3 days earlier, compared to unbaited control, suggesting a faster host detection by the encyrtid when LS is applied. These findings resulted in a significant increase in parasitism of mealybugs by A. sp. near pseudococci in LS baited traps relative to unbaited traps suggesting that the LS is used by the encyrtid as kairomone to ensure greater potential for host searching activity. Insecticide treatments significantly affected parasitization activity of A. sp. near pseudococci on mealybugs when compared to an untreated control with parasitoid release. The buprofezin, chlorpyriphos-methyl and untreated control with no parasitoid release treatments had statistically similar numbers of emerged parasitoids from exposed mealybugs. The obtained results provide evidence that, in the absence of conventional insecticides applications, the use of the LS could be a promising tool to improve and strengthen biological control of mealybugs by A. sp. near pseudococci within Sicilian vineyard conditions.

  3. Transcriptional responses of Italian ryegrass during interaction with Xanthomonas translucens pv. graminis reveal novel candidate genes for bacterial wilt resistance

    DEFF Research Database (Denmark)

    Wichmann, Fabienne; Asp, Torben; Widmer, Franko

    2011-01-01

    Xanthomonas translucens pv. graminis (Xtg) causes bacterial wilt, a severe disease of forage grasses such as Italian ryegrass (Lolium multiflorum Lam.). In order to gain a more detailed understanding of the genetic control of resistance mechanisms and to provide prerequisites for marker assisted...... selection, the partial transcriptomes of two Italian ryegrass genotypes, one resistant and one susceptible to bacterial wilt were compared at four time points after Xtg infection. A cDNA microarray developed from a perennial ryegrass (Lolium perenne) expressed sequence tag set consisting of 9,990 unique...

  4. Oak Wilt: People and Trees, A Community Approach to Management

    Science.gov (United States)

    J. Juzwik; S. Cook; L. Haugen; J. Elwell

    2004-01-01

    Version 1.3. This self-paced short course on CD-ROM was designed as a learning tool for urban and community foresters, city administrators, tree inspectors, parks and recreation staff, and others involved in oak wilt management.Click the "View or print this publication" link below to request your Oak Wilt: People and...

  5. Inheritance and identification of SCAR marker linked to bacterial wilt ...

    African Journals Online (AJOL)

    In the present work, the combinations (F1) were crossed between highly resistant and susceptible to bacterial wilt eggplant parents and its F2, BC1 segregation population plants were inoculated with race1 of Ralstonia solanacearum in greenhouse. In this paper, we reported that the inheritance of bacterial wilt resistance in ...

  6. Effects of Biochar Amendment on Tomato Bacterial Wilt Resistance and Soil Microbial Amount and Activity

    Directory of Open Access Journals (Sweden)

    Yang Lu

    2016-01-01

    Full Text Available Bacterial wilt is a serious soilborne disease of Solanaceae crops which is caused by Ralstonia solanacearum. The important role of biochar in enhancing disease resistance in plants has been verified; however, the underlying mechanism remains not fully understood. In this study, two different biochars, made from peanut shell (BC1 and wheat straw (BC2, were added to Ralstonia solanacearum-infected soil to explore the interrelation among biochar, tomato bacterial wilt, and soil microbial properties. The results showed that both BC1 and BC2 treatments significantly reduced the disease index of bacterial wilt by 28.6% and 65.7%, respectively. The populations of R. solanacearum in soil were also significantly decreased by biochar application. Ralstonia solanacearum infection significantly reduced the densities of soil bacteria and actinomycetes and increased the ratio of soil fungi/bacteria in the soil. By contrast, BC1 and BC2 addition to pathogen-infected soil significantly increased the densities of soil bacteria and actinomycetes but decreased the density of fungi and the ratios of soil fungi/bacteria and fungi/actinomycetes. Biochar treatments also increased soil neutral phosphatase and urease activity. Furthermore, higher metabolic capabilities of microorganisms by biochar application were found at 96 and 144 h in Biolog EcoPlates. These results suggest that both peanut and wheat biochar amendments were effective in inhibiting tomato bacterial wilt caused by R. solanacearum. The results suggest a relationship between the disease resistance of the plants and the changes in soil microbial population densities and activity.

  7. Risk analysis and guidelines for harvest activities in wisconsin oak timberlands to minimize oak wilt threat

    Science.gov (United States)

    Jennifer Juzwik; Jane Cummings-Carlson; Kyoko Scanlon

    2010-01-01

    Oaks (Quercus spp.) are an important species group in the forests of Wisconsin. The State’s timberland typed as oak-hickory forest was estimated at 2.9 million acres in 1996. Growing stock volume for red oak was estimated at 2.4 billion cubic feet, whereas select white oak volume was estimated to be 927 million cubic feet. Oak wilt, the oak disease...

  8. Development of SRAP, SRAP-RGA, RAPD and SCAR markers linked with a Fusarium wilt resistance gene in eggplant.

    Science.gov (United States)

    Mutlu, Nedim; Boyaci, Filiz Hatice; Göçmen, Münevver; Abak, Kazim

    2008-11-01

    Fusarium wilt (Fusarium oxysporum Schlecht. f. sp. melongenae) is a vascular disease of eggplant (Solanum melongena L.). The objectives of this work were (1) to confirm the monogenic inheritance of fusarium wilt resistance in eggplant, (2) to identify molecular markers linked to this resistance, and (3) to develop SCAR markers from most informative markers. We report the tagging of the gene for resistance to fusarium wilt (FOM) in eggplant using SRAP, RGA, SRAP-RGA and RAPD markers. Analysis of segregation data confirmed the monogenic inheritance of resistance. DNA from F(2) and BC(1) populations of eggplant segregating for fusarium wilt resistance was screened with 2,316 primer combinations to detect polymorphism. Three markers were linked within 2.6 cM of the gene. The codominant SRAP marker Me8/Em5 and dominant SRAP-RGA marker Em12/GLPL2 were tightly linked to each other and mapped 1.2 cM from the resistance gene, whereas RAPD marker H12 mapped 2.6 cM from the gene and on the same side as the other two markers. The SRAP marker was converted into two dominant SCAR markers that were confirmed to be linked to the resistance gene in the F(2,) BC(1) and F(2) of BC(3) generations of the same cross. These markers provide a starting point for mapping the eggplant FOM resistance gene in eggplant and for exploring the synteny between solanaceous crops for fusarium wilt resistance genes. The SCAR markers will be useful for identifying fusarium wilt-resistant genotypes in marker-assisted selection breeding programs using segregating progenies of the resistant eggplant progenitor used in this study.

  9. BIOLOGY AND CONTROL OF THE APPLE MEALYBUG PHENACOCCUS ACERIS (SIGNORET) IN BELGIUM.

    Science.gov (United States)

    Bangels, E; Peusens, G; Bylemans, D; Belien, T

    2014-01-01

    Although in general very rare, some outbreaks of the apple mealybug Phenococcus aceris (Signoret) (Hemiptera: Pseudococcidae) were reported in the Belgian fruit growing area recently. This insect is known to be geographically widespread, to have a broad host range and to infest apple trees. Damage at harvest is considerable when sooty molds, a consequence of the pest's honeydew production, cover the fruits. Indirect damage of an infection is caused in cherry cultivation through transmission of the Little cherry virus (LChV2). Efficacy trials were executed in infested apple orchards in the Belgian fruit growing area and the life cycle of the pest on apple was studied more into detail. Apple mealybugs are univoltine, overwinter as 2nd instar nymphs inside a white cocoon on the tree (under the bark, in crevices) and leave their overwintering site in early spring (mid March). On sunny days the nymphs become active, move around and attach to start feeding (mid April). After a final moult into the adult form, females lay eggs in a cocoon-like white structure (from flowering on). Following hatching (end May), massive numbers of young nymphs spread out on the underside of the leaves (mid June) where they feed through suction. In order to manage this pest the efficacy of several plant protection products was tested in two infested apple orchards. Results indicated that mortality was high after an application of compounds belonging to the neonicotinoid insecticides. Different application timings and control strategies are possible, with active nymphs being the most vulnerable life stage. The observed degree of parasitation in our trial orchards also indicates a biological control contribution of parasitic wasps that should be taken into account. A decent IPM-strategy based on our results solved the problem in both apple orchards.

  10. Evidence for gene flow between two sympatric mealybug species (Insecta; Coccoidea; Pseudococcidae.

    Directory of Open Access Journals (Sweden)

    Hofit Kol-Maimon

    Full Text Available Occurrence of inter-species hybrids in natural populations might be evidence of gene flow between species. In the present study we found evidence of gene flow between two sympatric, genetically related scale insect species--the citrus mealybug Planococcus citri (Risso and the vine mealybug Planococcus ficus (Signoret. These species can be distinguished by morphological, behavioral, and molecular traits. We employed the sex pheromones of the two respective species to study their different patterns of male attraction. We also used nuclear ITS2 (internal transcribed spacer 2 and mitochondrial COI (Cytochrome c oxidase sub unit 1 DNA sequences to characterize populations of the two species, in order to demonstrate the outcome of a possible gene flow between feral populations of the two species. Our results showed attraction to P. ficus pheromones of all tested populations of P. citri males but not vice versa. Furthermore, ITS2 sequences revealed the presence of 'hybrid females' among P. citri populations but not among those of P. ficus. 'hybrid females' from P. citri populations identified as P. citri females according to COI sequences. We offer two hypotheses for these results. 1 The occurrence of phenotypic and genotypic traits of P. ficus in P. citri populations may be attributed to both ancient and contemporary gene flow between their populations; and 2 we cannot rule out that an ancient sympatric speciation by which P. ficus emerged from P. citri might have led to the present situation of shared traits between these species. In light of these findings we also discuss the origin of the studied species and the importance of the pherotype phenomenon as a tool with which to study genetic relationships between congener scale insects.

  11. Biological control of chickpea wilt caused by fusarium oxysporum f.sp.ciceris

    International Nuclear Information System (INIS)

    Yousif, F. A.; Suliman, W. S.

    2010-01-01

    This study was conducted in an attempt to control chickpea (Cicer arietinum L.) wilt, caused by fusarium oxysporum f.sp. ciceris, using antagonistic properties of soil microorganisms. It also aimed at avoiding problems resulting from the use of chemical fungicides. A trichoderma sp. was isolated from the rhizosphere of a resistant chickpea variety (ICCV-2) and a bacillus sp. from the rhizosphere and rhizoplane of the same variety. Both microorganisms proved to be effective in controlling the disease. In addition, trichoderma harzianum, which was obtained from Giza Research Station in Egypt, was also antagonistic to fusarium oxysporum f. sp. ciceris Wilt incidence was significantly reduced when chickpea was grown in posts containing soil mixed with any of the three antagonists or when chickpea seeds were initially treated with the seed-dressing fungicide vincit at 2 ml/kg seeds. Trichoderma harzianum proved to be the best bioagent as it gave the lowest disease incidence. In the field, the two trichoderma spp. were as effective as vincit in causing reduction in the wilt incidence. At the higher concentration of 140 g/m''2, the two antagonists were effective throughout the growth period, but they were less effective at the lower concentration of 70 g/m''2 particularly at the seedling stage.(Author)

  12. Host-Induced Silencing of Pathogenicity Genes Enhances Resistance to Fusarium oxysporum Wilt in Tomato.

    Science.gov (United States)

    Bharti, Poonam; Jyoti, Poonam; Kapoor, Priya; Sharma, Vandana; Shanmugam, V; Yadav, Sudesh Kumar

    2017-08-01

    This study presents a novel approach of controlling vascular wilt in tomato by RNAi expression directed to pathogenicity genes of Fusarium oxysporum f. sp. lycopersici. Vascular wilt of tomato caused by Fusarium oxysporum f. sp. lycopersici leads to qualitative and quantitative loss of the crop. Limitation in the existing control measures necessitates the development of alternative strategies to increase resistance in the plants against pathogens. Recent findings paved way to RNAi, as a promising method for silencing of pathogenicity genes in fungus and provided effective resistance against fungal pathogens. Here, two important pathogenicity genes FOW2, a Zn(II)2Cys6 family putative transcription regulator, and chsV, a putative myosin motor and a chitin synthase domain, were used for host-induced gene silencing through hairpinRNA cassettes of these genes against Fusarium oxysporum f. sp. lycopersici. HairpinRNAs were assembled in appropriate binary vectors and transformed into tomato plant targeting FOW2 and chsV genes, for two highly pathogenic strains of Fusarium oxysporum viz. TOFOL-IHBT and TOFOL-IVRI. Transgenic tomatoes were analyzed for possible attainment of resistance in transgenic lines against fungal infection. Eight transgenic lines expressing hairpinRNA cassettes showed trivial disease symptoms after 6-8 weeks of infection. Hence, the host-induced posttranscriptional gene silencing of pathogenicity genes in transgenic tomato plants has enhanced their resistance to vascular wilt disease caused by Fusarium oxysporum.

  13. Effects of soil application of fly ash on the fusarial wilt on tomato cultivars

    Energy Technology Data Exchange (ETDEWEB)

    Khan, M.R.; Singh, W.N. [Aligarh Muslim University, Aligarh (India). Dept. of Plant Protection, Rafi Ahmad Kidwai Institute of Agricultural Science

    2001-07-01

    A study was carried out in microplots to evaluate the effect of fly ash on the plant growth and yield of tomato cultivars, Pusa Ruby, Pusa Early Dwarf and New Uday, and on wilt disease caused by Fusarium oxysporum f. sp. lycopersici. Fly ash was applied to soil by broadcast or in rows at the rate of 1, 2, 3 and 4 kg ash m{sup -2} in place of inorganic fertilizers. In control plots, NPK (about 40 : 20 : 20 kg acre{sup -1}) and compost were added in place of fly ash. Ash application greatly increased the soil contents of P, K, B, Ca, Mg, Mn, Zn, carbonates, bicarbonates and sulphates. Plants grown in the ash-treated plots, especially at 3 or 4 kg dose, showed luxuriant growth and greener foliage, and plant growth and yield of the three cultivars were significantly increased in comparison with the plants grown in plots without fly ash. The wilt fungus, F. oxysporum f. sp. lycopersiciat the inoculum level of 2 g plant{sup -1} caused significant suppression of growth and yield in all three cultivars. Application of fly ash, however, checked the suppressive effect of the fungus, leading to a significant increase in the considered variables compared with the inoculated control. Soil population of the fungus gradually decreased with an increase in ash dose. Row application was found to be relatively more effective in enhancing the yield of tomato cultivars and suppressing the wilt disease.

  14. Wilted cucumber plants infected by Fusarium oxysporum f. sp. cucumerinum do not suffer from water shortage.

    Science.gov (United States)

    Sun, Yuming; Wang, Min; Li, Yingrui; Gu, Zechen; Ling, Ning; Shen, Qirong; Guo, Shiwei

    2017-09-01

    Fusarium wilt is primarily a soil-borne disease and results in yield loss and quality decline in cucumber (Cucumis sativus). The main symptom of fusarium wilt is the wilting of entire plant, which could be caused by a fungal toxin(s) or blockage of water transport. To investigate whether this wilt arises from water shortage, the physiological responses of hydroponically grown cucumber plants subjected to water stress using polyethylene glycol (PEG, 6000) were compared with those of plants infected with Fusarium oxysporum f. sp. cucumerinum (FOC). Parameters reflecting plant water status were measured 8d after the start of treatment. Leaf gas exchange parameters and temperature were measured with a LI-COR portable open photosynthesis system and by thermal imaging. Chlorophyll fluorescence and chloroplast structures were assessed by imaging pulse amplitude-modulated fluorometry and transmission electron microscopy, respectively. Cucumber water balance was altered after FOC infection, with decreased water absorption and hydraulic conductivity. However, the responses of cucumber leaves to FOC and PEG differed in leaf regions. Under water stress, measures of lipid peroxidation (malondialdehyde) and chlorophyll fluorescence indicated that the leaf edge was more seriously injured, with a higher leaf temperature and disrupted leaf water status compared with the centre. Here, abscisic acid (ABA) and proline were negatively correlated with water potential. In contrast, under FOC infection, membrane damage and a higher temperature were observed in the leaf centre while ABA and proline did not vary with water potential. Cytologically, FOC-infected cucumber leaves exhibited circular chloroplasts and swelled starch grains in the leaf centre, in which they again differed from PEG-stressed cucumber leaves. This study illustrates the non-causal relationship between fusarium wilt and water transport blockage. Although leaf wilt occurred in both water stress and FOC infection, the

  15. Three new species of mealybug (Hemiptera, Coccomorpha, Pseudococcidae) on persimmon fruit trees (Diospyros kaki) in southern Brazil.

    Science.gov (United States)

    Pacheco da Silva, Vitor C; Kaydan, Mehmet Bora; Germain, Jean-François; Malausa, Thibaut; Botton, Marcos

    2016-01-01

    Brazil has the greatest insect diversity in the world; however, little is known about its scale insect species (Hemiptera: Coccomorpha). Mealybugs (Pseudococcidae) have been found in at least 50% of persimmon orchards Diospyros kaki L. in the southern part of the country. In this study three new mealybug species on persimmon trees located in the Serra Gaúcha Region, RS, Brazil, namely, Anisococcus granarae Pacheco da Silva & Kaydan, sp. n., Ferrisia kaki Kaydan & Pacheco da Silva, sp. n. and Pseudococcus rosangelae Pacheco da Silva & Kaydan, sp. n. are described. In addition, an identification key for the genera occurring on fruit orchards and vineyards in Brazil is provided, together with illustrations and molecular data for the new species.

  16. Transfer of lead (Pb) in the soil-plant-mealybug-ladybird beetle food chain, a comparison between two host plants.

    Science.gov (United States)

    Zhang, Can; Wang, Xingmin; Ashraf, Umair; Qiu, Baoli; Ali, Shaukat

    2017-09-01

    Contamination of soil with heavy metals has become an issue of concern on global scale. This study investigates the translocation of lead (Pb) along the soil - plant (eggplant and tomato) - mealybug (Dysmicoccus neobrevipes) - ladybird beetle (Cryptolaemus montrouzieri) food chain. Soil amendments used for this study were adjusted to 0, 25, 50 and 100mg/kg of Pb (w/w). The results revealed significantly higher transfer of Pb in tomato when compared to eggplant. Bio-magnification of Pb (2-4 times) was observed for soil - root transfer whereas Pb was bio-minimized in later part of food chain (shoot - mealybug - ladybird transfer). A dose dependent increase in transfer of Pb across the multi-trophic food chain was observed for both host plants. A decrease in coefficients of Pb transfer (from root - shoot and shoot - mealybug) was observed with increase in Pb concentrations. Our results also showed removal of Pb from the bodies of ladybird beetle during metamorphosis. Further studies are required to explain the mechanisms or physiological pathways involved in the bio-minimization of Pb across the food chain. Copyright © 2017 Elsevier Inc. All rights reserved.

  17. Ecological implications of Laurel Wilt infestation on Everglades Tree Islands, southern Florida

    Science.gov (United States)

    Snyder, James R.

    2014-01-01

    There is a long history of introduced pests attacking native forest trees in the United States (Liebhold and others, 1995; Aukema and others, 2010). Well-known examples include chestnut blight that decimated the American chestnut (Castanea dentata), an extremely important tree in the eastern United States, both as a food source for wildlife and humans and for the wood; Dutch elm disease that attacks native elms (Ulmus spp.), including those commonly planted as shade trees along city streets; and the balsam wooly adelgid (Adelges piceae), an insect that is destroying Fraser firs (Abies fraseri) in higher elevations of Great Smoky Mountains National Park. Laurel wilt, a fungal disease transmitted by the redbay ambrosia beetle (Xyleborus glabratus), is a 21st-century example of an introduced forest pest that attacks native tree species in the laurel family (Lauraceae) (Mayfield, 2007; Hulcr and Dunn, 2011).The introduction of laurel wilt disease has been traced to the arrival of an Asian ambrosia beetle (Xyleborus glabratus) at Port Wentworth, Georgia, near Savannah, in 2002, apparently accidently introduced in wooden shipping material (Mayfield, 2007). Within the next 2 years, it was determined that the non-native wood-boring insect was the vector of an undescribed species of fungus, responsible for killing large numbers of red bay (Persea borbonia) trees in the surrounding area. Dispersing female redbay ambrosia beetles drill into live trees and create tunnels in the wood. They carry with them fungal spores in specialized organs called mycangia at the base of each mandible and sow the spores in the tunnels they excavate. The fungus, since named Raffaelea lauricola (Harrington and others, 2008), is the food source for adults and larvae. The introduction of Raffaelea lauricola causes the host plant to react in such a way as to block the vascular tissue, resulting in loss of water conduction, wilt, and death (Kendra and others, 2013).Although first seen in red bay

  18. Hairy root transgene expression analysis of a secretory peroxidase (PvPOX1) from common bean infected by Fusarium wilt.

    Science.gov (United States)

    Xue, Renfeng; Wu, Xingbo; Wang, Yingjie; Zhuang, Yan; Chen, Jian; Wu, Jing; Ge, Weide; Wang, Lanfen; Wang, Shumin; Blair, Matthew W

    2017-07-01

    Plant peroxidases (POXs) are one of the most important redox enzymes in the defense responses. However, the large number of different plant POX genes makes it necessary to carefully confirm the function of each paralogous POX gene in specific tissues and disease interactions. Fusarium wilt is a devastating disease of common bean caused by Fusarium oxysporum f. sp. phaseoli. In this study, we evaluated a peroxidase gene, PvPOX1, from a resistant common bean genotype, CAAS260205 and provided direct evidence for PvPOX1's role in resistance by transforming the resistant allele into a susceptible common bean genotype, BRB130, via hairy root transformation using Agrobacterium rhizogenes. Analysis of PvPOX1 gene over-expressing hairy roots showed it increased resistance to Fusarium wilt both in the roots and the rest of transgenic plants. Meanwhile, the PvPOX1 expressive level, the peroxidase activity and hydrogen peroxide (H 2 O 2 ) accumulation were also enhanced in the interaction. The result showed that the PvPOX1 gene played an essential role in Fusarium wilt resistance through the occurrence of reactive oxygen species (ROS) induced hypersensitive response. Therefore, PvPOX1 expression was proven to be a valuable gene for further analysis which can strengthen host defense response against Fusarium wilt through a ROS activated resistance mechanism. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Leaf reddening disease of pineapple in Ghana | Awuah | Ghana ...

    African Journals Online (AJOL)

    Mealybugs and ants are sometimes, but not always, associated with diseased plants. Nematodes of the genera Pratylenchus, Aphelenchus and. Helicotylenchus have been recovered, though infrequently, from roots and root zone soil of diseased plants. Based on these preliminary results and field observations, it is ...

  20. Laurel Wilt in Natural and Agricultural Ecosystems: Understanding the Drivers and Scales of Complex Pathosystems

    Directory of Open Access Journals (Sweden)

    Randy C. Ploetz

    2017-02-01

    Full Text Available Laurel wilt kills members of the Lauraceae plant family in the southeastern United States. It is caused by Raffaelea lauricola T.C. Harr., Fraedrich and Aghayeva, a nutritional fungal symbiont of an invasive Asian ambrosia beetle, Xyleborus glabratus Eichhoff, which was detected in Port Wentworth, Georgia, in 2002. The beetle is the primary vector of R. lauricola in forests along the southeastern coastal plain of the United States, but other ambrosia beetle species that obtained the pathogen after the initial introduction may play a role in the avocado (Persea americana Miller pathosystem. Susceptible taxa are naïve (new-encounter hosts that originated outside Asia. In the southeastern United States, over 300 million trees of redbay (P. borbonia (L. Spreng. have been lost, and other North American endemics, non-Asian ornamentals and avocado—an important crop that originated in MesoAmerica—are also affected. However, there are no reports of laurel wilt on the significant number of lauraceous endemics that occur in the Asian homeland of R. lauricola and X. glabratus; coevolved resistance to the disease in the region has been hypothesized. The rapid spread of laurel wilt in the United States is due to an efficient vector, X. glabratus, and the movement of wood infested with the insect and pathogen. These factors, the absence of fully resistant genotypes, and the paucity of effective control measures severely constrain the disease’s management in forest ecosystems and avocado production areas.

  1. Trichoderma harzianum in combination with sheep manure amendment enhances soil suppressiveness of Fusarium wilt of tomato

    Directory of Open Access Journals (Sweden)

    R. M. Barakat

    2010-01-01

    Full Text Available The effect that the biocontrol agent Trichoderma harzianum (isolate Jn14 in combination with an amendment of sheep manure has on the soil suppressiveness of Fusarium wilt of tomato was investigated over a 28-month period. A combination of T. harzianum and organic amendment at concentrations (w:w of 6 and 10% reduced tomato wilt by 21–36 % and 29–36% respectively, after 0–28 months of soil incubation. When the amendment was added at concentration of 2%, the wilt was suppressed only after 18–28 months. A combination of T. harzianum and the amendment at 6% also increased tomato plant fresh weights by 52% after 28 months, and the 10% amendment increased fresh weights by 56, 40, and 63%, after 18, 24, and 28 months respectively, compared to the experimental controls. Organic amendment at the higher concentrations further stimulated T. harzianum populations, enhanced microbial activity against Fusarium oxysporum in the soil and reduced pathogen populations. Without T. harzianum, the organic amendment at a concentration of 10% reduced disease by only 22, 24, and 23% and only after 18, 24 and 28 months of soil incubation respectively, compared with the controls. However, tomato wilt was not reduced at a 2% manure concentration in less than 12 months of incubation. Organic amendment alone at 6 and 10% reduced the pathogen population by 25% and 37% respectively after 28 months of soil incubation compared with the control. T. harzianum produced fungitoxic metabolites that reduced mycelial growth of Fusarium by 37% and conidium germination by 55% when the pathogen was grown on potato dextrose agar amended with a T. harzianum culture filtrate.

  2. Generation and characterization of mutants of tomato spotted wilt virus

    NARCIS (Netherlands)

    Oliveira Resende, de R.

    1993-01-01

    In nature, tospoviruses like tomato spotted wilt virus (TSWV) are exclusively transmitted by thrips species (Sakimura, 1962) producing numerous enveloped virions during infection, which accumulate in the cisternae of the endoplasmatic. reticulum. system (Kitajima, 1965; Milne, 1970; Ie,

  3. [Effects of nitrogen application rate on faba bean fusarium wilt and rhizospheric microbial metabolic functional diversity].

    Science.gov (United States)

    Dong, Yan; Yang, Zhi-xian; Dong, Kun; Tang, Li; Zheng, Yi; Hu, Guo-bin

    2013-04-01

    A field plot experiment was conducted to study the effects of different nitrogen (N) application rates on the microbial functional diversity in faba bean rhizosphere and the relationships between the microbial functional diversity and the occurrence of faba bean fusarium wilt. Four nitrogen application rates were installed, i. e. , N0(0 kg hm-2 , N1 (56. 25 kg hm-2) , N2(112. 5 kg hm-2), and N3 (168.75 kg hm-2), and Biolog microbial analysis system was applied to study the damage of faba bean fusarium wilt and the rhizospheric microbial metabolic functional diversity. Applying N (N1 N2, and N3) decreased the disease index of faba bean fusarium wilt and the quantity of Fusarium oxysporum significantly, and increased the quantities of bacteria and actinomyces and the ratios of bacteria/fungi and actinomyces/fungi significantly, with the peak values of bacteria and actinomyces, bacteria/fungi, and actinomyces/fungi, and the lowest disease index and F. oxysporum density in N2. As compared with N0, applying N increased the AWCD value significantly, but the effects of different N application rates on the ability of rhizospheric microbes in utilizing six types of carbon sources had definite differences. Under the application of N, the utilization rates of carbohydrates, carboxylic acids, and amino acids by the rhizospheric microbes were higher. Principal component analysis demonstrated that applying N changed the rhizospheric microbial community composition obviously, and the carbohydrates, carboxylic acids, and amino acids were the sensitive carbon sources differentiating the changes of the microbial community induced by N application. Applying N inhibited the utilization of carbohydrates and carboxylic acids but improved the utilization of amino acids and phenolic acids by the rhizospheric microbes, which could be one of the main reasons of applying N being able to reduce the harm of faba bean fusarium wilt. It was suggested that rationally applying N could increase the

  4. Effects of gamma irradiation on different stages of mealybug Dysmicoccus neobrevipes (Hemiptera: Pseudococcidae)

    Science.gov (United States)

    The, Doan Thi; Khanh, Nguyen Thuy; Lang, Vo Thi Kim; Van Chung, Cao; An, Tran Thi Thien; Thi, Nguyen Hoang Hanh

    2012-01-01

    Utilization of phytosanitary irradiation as a potential treatment to disinfest agricultural commodities in trade has expanded rapidly in the recent years. Cobalt-60 gamma ray target doses of 100, 150, 200 and 250 Gy were used to irradiate immatures and adults of Dysmicoccus neobrevipes (Beardsley) (Hemiptera: Pseudococcidae) infesting dragon fruits to find the most tolerant stage and the most optimal dose range for quarantine treatment. In general, irradiation affected significantly all life stages of D. neobrevipes mortality and adult reproduction. The pattern of tolerance to irradiation in D. neobrevipes was 1st instars<2nd instars<3rd instarsmealybug.

  5. Reproducibility of suppression of Pythium wilt of cucumber by compost

    Directory of Open Access Journals (Sweden)

    Mauritz Vilhelm Vestberg

    2014-10-01

    Full Text Available There is increasing global interest in using compost to suppress soil-borne fungal and bacterial diseases and nematodes. We studied the reproducibility of compost suppressive capacity (SC against Pythium wilt of cucumber using nine composts produced by the same composting plant in 2008 and 2009. A bioassay was set up in a greenhouse using cucumber inoculated with two strains of Pythium. The composts were used as 20% mixtures (v:v of a basic steam-sterilized light Sphagnum peat and sand (3:1, v:v. Shoot height was measured weekly during the 5-week experiment. At harvest, the SC was calculated as the % difference in shoot dry weight (DW between non-inoculated and inoculated cucumbers. The SC was not affected by year of production (2008 or 2009, indicating reproducibility of SC when the raw materials and the composting method are not changed. Differences in shoot height were not as pronounced as those for shoot DW. The results were encouraging, but further studies are still needed for producing compost with guaranteed suppressiveness properties.

  6. Analyses of Fusarium wilt race 3 resistance in Upland cotton (Gossypium hirsutum L.).

    Science.gov (United States)

    Abdullaev, Alisher A; Salakhutdinov, Ilkhom B; Egamberdiev, Sharof Sh; Kuryazov, Zarif; Glukhova, Ludmila A; Adilova, Azoda T; Rizaeva, Sofiya M; Ulloa, Mauricio; Abdurakhmonov, Ibrokhim Y

    2015-06-01

    Fusarium wilt [Fusarium oxysporum f.sp. vasinfectum (FOV) Atk. Sny & Hans] represents a serious threat to cotton (Gossypium spp.) production. For the last few decades, the FOV pathogen has become a significant problem in Uzbekistan causing severe wilt disease and yield losses of G. hirsutum L. cultivars. We present the first genetic analyses of FOV race 3 resistance on Uzbek Cotton Germplasm with a series of field and greenhouse artificial inoculation-evaluations and inheritance studies. The field experiments were conducted in two different sites: the experimental station in Zangiota region-Environment (Env) 1 and the Institute of Cotton Breeding (Env-2, Tashkent province). The Env-1 was known to be free of FOV while the Env-2 was known to be a heavily FOV infested soil. In both (Env-1 and Env-2) of these sites, field soil was inoculated with FOV race 3. F2 and an F3 Upland populations ("Mebane B1" × "11970") were observed with a large phenotypic variance for plant survival and FOV disease severity within populations and among control or check Upland accessions. Wilt symptoms among studied F2 individuals and F3 families significantly differed depending on test type and evaluation site. Distribution of Mendelian rations of susceptible (S) and resistant (R) phenotypes were 1S:1R field Env-1 and 3S:1R field Env-2 in the F2 population, and 1S:3R greenhouse site in the F3 population. The different segregation distribution of the Uzbek populations may be explained by differences in FOV inoculum level and environmental conditions during assays. However, genetic analysis indicated a recessive single gene action under high inoculum levels or disease pressure for FOV race 3 resistance. Uzbek germplasm may be more susceptible than expected to FOV race 3, and sources of resistance to FOV may be limited under the FOV inoculum levels present in highly-infested fields making the breeding process more complex.

  7. The influence of different concentrations of bio-organic fertilizer on cucumber Fusarium wilt and soil microflora alterations.

    Directory of Open Access Journals (Sweden)

    Nan Huang

    Full Text Available Fusarium wilt is one of the main diseases of cucumber, and bio-organic fertilizer has been used to control Fusarium wilt. In this study, a pot experiment was conducted to evaluate the effects of bio-organic fertilizer applied at four levels on the suppression of Fusarium wilt disease in cucumber, the soil physico-chemical properties and the microbial communities. In comparison with the control (CK, low concentrations of bio-organic fertilizer (BIO2.5 and BIO5 did not effectively reduce the disease incidence and had little effect on soil microorganisms. High concentrations of bio-organic fertilizer (BIO10 and BIO20 significantly reduced the disease incidence by 33.3%-66.7% and the production was significantly improved by 83.8%-100.3%. The soil population of F. oxysporum f. sp. cucumerinum was significantly lower in bio-organic fertilizer treatments, especially in BIO10 and BIO20. The microorganism activity increased with the bio-organic fertilizer concentration. High-throughput sequencing demonstrated that, at the order level, Sphingomonadales, Bacillales, Solibacterales and Xylariales were significantly abundant in BIO10 and BIO20 soils. At the genus level, the abundance and composition of bacterial and fungal communities in BIO10 and BIO20 were similar, illustrating that high concentrations of bio-organic fertilizer activated diverse groups of microorganisms. Redundancy analysis (RDA showed that Xanthomonadales, Sphingomonadales, Bacillales, Orbiliales, Sordariales, and Mucorales occurred predominantly in the BIO10 and BIO20. These microorganisms were related to the organic matter, available potassium and available phosphorus contents. In conclusion, a high concentration of bio-organic fertilizer application suppressed the Fusarium wilt disease and increased cucumber production after continuous cropping might through improving soil chemical condition and manipulating the composition of soil microbial community.

  8. Mealybugs (Hemiptera: Coccomorpha: Pseudococcidae) attacking Hibiscus rosa-sinensis L. in Malaysia, with two new country records

    Science.gov (United States)

    Sartiami, Dewi; Watson, Gillian W.; Mohamad Roff, M. N.; Idris, A. B.

    2016-11-01

    A survey of mealybugs (Hemiptera: Coccomorpha: Pseudococcidae) attacking the national flower of Malaysia, Hibiscus rosa-sisnensis L. and Hibiscus spp. (Malvaceae) was conducted in Selangor and Kuala Lumpur, Malaysia, from January to March 2016. Adult females were mounted on microscope slides in Canada balsam. The five species identified were Ferrisia dasylirii (Cockerell), Maconellicoccus hirsutus (Green), Paracoccus marginatus Williams and Granara de Willink, Phenacoccus solenopsis (Tinsley) and Pseudococcus jackbeardsleyi Gimpel & Miller. Two of these, the invasive species Ferrisia dasylirii and P. solenopsis were introduced and first recorded in Malaysia.

  9. First report of Fusarium decemcellulare causing inflorescence wilt, vascular and flower necrosis of rambutan (Nephelium lappaceum), longan (Dimocarpus longan) and mango (Mangifera indica)

    Science.gov (United States)

    Longan, mango and rambutan are very important fruit crops in Puerto Rico. During a disease survey in Puerto Rico conducted from 2008 to 2010, 50% of the inflorescences were affected with inflorescence wilt, flower and vascular necrosis at 70% of the fields of rambutan and longan at the USDA-ARS Rese...

  10. Draft genome sequence of the fungus associated with oak-wilt mortality in South Korea, Raffaelea quercus-mongolicae KACC44405

    Science.gov (United States)

    Jongbum Jeon; Ki-Tae Kim; Hyeunjeong Song; Gir-Won Lee; Kyeongchae Cheong; Hyunbin Kim; Gobong Choi; Yong-Hwan Lee; Jane E. Stewart; Ned B. Klopfenstein; Mee-Sook Kim

    2017-01-01

    The fungus Raffaelea quercus-mongolicae is the causal agent of Korean oak wilt, a disease associated with mass mortality of oak trees (e.g., Quercus spp.). The fungus is vectored and dispersed by the ambrosia beetle, Platypus koryoensis. Here, we present the 27.0-Mb draft genome sequence of R. quercus-mongolicae strain KACC44405.

  11. Biochemical markers assisted screening of Fusarium wilt resistant Musa paradisiaca (L.) cv. puttabale micropropagated clones.

    Science.gov (United States)

    Venkatesh; Krishna, V; Kumar, K Girish; Pradeepa, K; Kumar, S R Santosh; Kumar, R Shashi

    2013-07-01

    An efficient protocol was standardized for screening of panama wilt resistant Musa paradisiaca cv. Puttabale clones, an endemic cultivar of Karnataka, India. The synergistic effect of 6-benzyleaminopurine (2 to 6 mg/L) and thidiazuron (0.1 to 0.5 mg/L) on MS medium provoked multiple shoot induction from the excised meristem. An average of 30.10 +/- 5.95 shoots was produced per propagule at 4 mg/L 6-benzyleaminopurine and 0.3 mg/L thidiazuron concentrations. Elongation of shoots observed on 5 mg/L BAP augmented medium with a mean length of 8.38 +/- 0.30 shoots per propagule. For screening of disease resistant clones, multiple shoot buds were mutated with 0.4% ethyl-methane-sulfonate and cultured on MS medium supplemented with Fusarium oxysporum f. sp. cubense (FOC) culture filtrate (5-15%). Two month old co-cultivated secondary hardened plants were used for screening of disease resistance against FOC by the determination of biochemical markers such as total phenol, phenylalanine ammonia lyase, oxidative enzymes like peroxidase, polyphenol oxidase, catalase and PR-proteins like chitinase, beta-1-3 glucanase activities. The mutated clones of M. paradisiaca cv. Puttabale cultured on FOC culture filtrate showed significant increase in the levels of biochemical markers as an indicative of acquiring disease resistant characteristics to FOC wilt.

  12. The potential distribution of cassava mealybug (Phenacoccus manihoti, a threat to food security for the poor.

    Directory of Open Access Journals (Sweden)

    Tania Yonow

    Full Text Available The cassava mealybug is a clear and present threat to the food security and livelihoods of some of the world's most impoverished citizens. Niche models, such as CLIMEX, are useful tools to indicate where and when such threats may extend, and can assist with planning for biosecurity and the management of pest invasions. They can also contribute to bioeconomic analyses that underpin the allocation of resources to alleviate poverty. Because species can invade and establish in areas with climates that are different from those that are found in their native range, it is essential to define robust range-limiting mechanisms in niche models. To avoid spurious results when applied to novel climates, it is necessary to employ cross-validation techniques spanning different knowledge domains (e.g., distribution data, experimental results, phenological observations. We build upon and update a CLIMEX niche model by Parsa et al. (PloS ONE 7: e47675, correcting inconsistent parameters and re-fitting it based on a careful examination of geographical distribution data and relevant literature. Further, we consider the role of irrigation, the known distribution of cassava production and a targeted review of satellite imagery to refine, validate and interpret our model and results. In so doing, we bring new insights into the potential spread of this invasive insect, enabling us to identify potential bio-security threats and biological control opportunities. The fit of the revised model is improved, particularly in relation to the wet and dry limits to establishment, and the parameter values are biologically plausible and accord with published scientific literature.

  13. Male behaviors reveal multiple pherotypes within vine mealybug Planococcus ficus (Signoret) (Hemiptera; Pseudococcidae) populations

    Science.gov (United States)

    Kol-Maimon, Hofit; Levi-Zada, Anat; Franco, José Carlos; Dunkelblum, Ezra; Protasov, Alex; Eliyaho, Miriam; Mendel, Zvi

    2010-12-01

    The vine mealybug (VM) females collected in Israel produce two sex pheromone compounds: lavandulyl senecioate (LS) and ( S)-lavandulyl isovalerate (LI). The males display ambiguous behavior to LI: repulsion in the vineyard and attraction of laboratory-reared males. We addressed the question of individual male behavior, i.e., do males respond to both LS and LI, or might they display a distinct response to each of the two pheromone compounds. We compared male pherotype frequencies between wild-caught and laboratory-reared populations. Then, we examined the relationship between pherotype composition and male capture rates in pheromone traps. Finally, we addressed the heredity of the pherotypes. The Israeli VM populations contain nine different male pherotypes, as defined according to the male behavior to pheromone compounds. The studied Portuguese populations included five of the nine pherotypes; none of the Portuguese males were attracted to LI. It seems that the high frequency of males that were attracted to LI is related to dense VM populations. It is hypothesized that selection for the male pherotypes, I males, those that respond to LI, occur under high-density rearing conditions. This may result from shorter development times of males and females that produce more I male pherotypes. The lower relative frequency of trapping of males in LI-baited traps than expected from the percentage determined in a Petri dish arena suggests that males that respond solely to LS (S males) are better fliers. The results also suggest that the pherotype trait is inherited by both sexes of the VM.

  14. Sexual versus Asexual Reproduction: Distinct Outcomes in Relative Abundance of Parthenogenetic Mealybugs following Recent Colonization.

    Science.gov (United States)

    Tabata, Jun; Ichiki, Ryoko T; Tanaka, Hirotaka; Kageyama, Daisuke

    2016-01-01

    Asexual reproduction, including parthenogenesis in which embryos develop within a female without fertilization, is assumed to confer advantages over sexual reproduction, which includes a "cost of males." Sexual reproduction largely predominates in animals, however, indicating that this cost is outweighed by the genetic and/or ecological benefits of sexuality, including the acquisition of advantageous mutations occurring in different individuals and the elimination of deleterious mutations. But the evolution of sexual reproduction remains unclear, because we have limited examples that demonstrate the relative success of sexual lineages in the face of competition from asexual lineages in the same environment. Here we investigated a sympatric occurrence of sexual and asexual reproduction in the pineapple mealybug, Dysmicoccus brevipes. This pest invaded southwestern Japan, including Okinawa and Ishigaki Islands, in the 1930s in association with imported pineapple plants. Our recent censuses demonstrated that on Okinawa sexually reproducing individuals can coexist with and even dominate asexual individuals in the presence of habitat and resource competition, which is considered to be severe for this nearly immobile insect. Molecular phylogeny based on partial DNA sequences in the mitochondrial and nuclear genomes, as well as the endosymbiotic bacterial genome, revealed that the asexual lineage diverged from a common sexual ancestor in the relatively recent past. In contrast, only the asexual lineage exhibiting obligate apomictic thelytoky was discovered on Ishigaki. Co-existence of the two lineages cannot be explained by the results of laboratory experiments, which showed that the intrinsic rate of increase in the sexual lineage was not obviously superior to that of the asexual lineage. Differences in biotic and/or abiotic selective forces operating on the two islands might be the cause of this discrepancy. This biological system offers a unique opportunity to assess

  15. Irradiation as a quarantine treatment for the solenopsis mealybug, Phenacoccus solenopsis

    International Nuclear Information System (INIS)

    Huang, Fang; Li, Weidi; Li, Xiuqiong; Bei, Yawei; Lin, Wencai; Lu, Yaobin; Wang, Bingkui

    2014-01-01

    Phenacoccus solenopsis is an aggressively invasive species that targets agricultural and ornamental plants, thereby threatening the world cotton industry and other crops. P. solenopsis has been listed as a quarantine insect in Europe and China. The utilization of phytosanitary irradiation as a potential treatment for disinfesting agricultural commodities in trade has expanded rapidly in recent years. A reasonable dose of radiation to eliminate P. solenopsis needs to be determined, taking into account the side effects of radiation on agricultural products and the species-specific tolerance of the insect to radiation. We applied radiation ranging from 50 to 200 Gy to P. solenopsis to determine the optimal dose. Both the radiation dose and the developmental stage of the insect were independent variables. Higher doses of radiation or lesser mature insect stages provided more effective treatment. In nymphs, a radiation dose of 100 Gy caused extinction of the irradiated population by disrupting ovary development, while 150 Gy caused 100% mortality. In adults, all tested doses of irradiation did not affect longevity, but we were able to prevent reproduction with high (150 and 200 Gy) doses. In P. solenopsis, a 100 Gy dose of radiation could eliminate the irradiated population in two generations. The mortality curve showed a steep slope beyond 150 Gy; thus, if killing all of the insects in a shorter amount of time is necessary, 200 Gy may be a reasonable dose for the quarantine treatment of the solenopsis mealybug. - Highlights: • Both ‘radiation dose’ and ‘irradiated insect stage’ are important factors. • 100-Gy irradiation could achieve population extinction in two generations. • 200 Gy should be a reasonable dose in the quarantine treatment

  16. The cotton mealybug, Phenacoccus solenopsis Tinsley (Hemiptera: Pseudococcidae as a new menace to cotton in Egypt and its chemical control

    Directory of Open Access Journals (Sweden)

    El-Zahi El-Zahi Saber

    2016-04-01

    Full Text Available The cotton mealybug, Phenacoccus solenopsis Tinsley (Hemiptera: Pseudococcidae is a polyphagous sap sucking insect with a wide geographical and host range causing severe losses in economically important crops. This study represents the first record of P. solenopsis as a new insect attacking cotton plants (Gossypium barbadense var. Giza 86 in Kafr El-Sheikh governorate, Egypt. The insect was noticed on cotton plants for the first time during its growing season of 2014. The mealybug specimens were collected from infested cotton plants and identified as P. solenopsis. In an attempt to control this pest, eight toxic materials viz., imidacloprid, thiamethoxam, flonicamid, emamectin-benzoate, chlorpyrifos, methomyl, deltamethrin and mineral oil (KZ-oil, belonging to different chemical groups, were tested for their influence against P. solenopsis on cotton under field conditions. Methomyl, imidacloprid, thiamethoxam and chlorpyrifos showed the highest efficacy against P. solenopsis recording 92.3 to 80.4% reduction of the insect population. Flonicamid, emamectin-benzoate and KZ-oil failed to exhibit sufficient P. solenopsis control.

  17. Association mapping to discover significant marker-trait associations for resistance against fusarium wilt variant 2 in pigeonpea [Cajanus cajan (L.) Millspaugh] using SSR markers.

    Science.gov (United States)

    Patil, Prakash G; Dubey, Jyotirmay; Bohra, Abhishek; Mishra, R K; Saabale, P R; Das, Alok; Rathore, Meenal; Singh, N P

    2017-08-01

    Pigeonpea production is severely constrained by wilt disease caused by Fusarium udum. In the current study, we discover the putative genomic regions that control resistance response to variant 2 of fusarium wilt using association mapping approach. The association panel comprised of 89 diverse pigeonpea genotypes including seven varieties, three landraces and 79 germplasm lines. The panel was screened rigorously for 3 consecutive years (2013-14, 2014-15 and 2015-2016) against variant 2 in a wilt-sick field. A total of 65 pigeonpea specific hypervariable SSR markers (HASSRs) were screened representing seven linkage groups and 29 scaffolds of the pigeonpea genome. A total of 181 alleles were detected, with average values of gene diversity and polymorphism information content (PIC) of 0.55 and 0.47, respectively. Further analysis using model based (STRUCTURE) and distance based (clustering) approaches separated the entire pigeonpea collection into two distinct subgroups (K = 2). The marker trait associations (MTAs) were established based on three-year wilt incidence data and SSR dataset using a unified mixed linear model. Consequently, six SSR markers were identified, which were significantly associated with wilt resistance and explained up to 6% phenotypic variance (PV) across the years. Among these SSRs, HASSR18 was found to be the most stable and significant, accounting for 5-6% PV across the years. To the best of our knowledge, this is the first report of identification of favourable alleles for resistance to variant 2 of Fusarium udum in pigeonpea using association mapping. The SSR markers identified here will greatly facilitate marker assisted resistance breeding against fusarium wilt in pigeonpea.

  18. Application of Sodium Silicate Enhances Cucumber Resistance to Fusarium Wilt and Alters Soil Microbial Communities

    Directory of Open Access Journals (Sweden)

    Xingang Zhou

    2018-05-01

    Full Text Available Exogenous silicates can enhance plant resistance to pathogens and change soil microbial communities. However, the relationship between changes in soil microbial communities and enhanced plant resistance remains unclear. Here, effects of exogenous sodium silicate on cucumber (Cucumis sativus L. seedling resistance to Fusarium wilt caused by the soil-borne pathogen Fusarium oxysporum f.sp. cucumerinum Owen (FOC were investigated by drenching soil with 2 mM sodium silicate. Soil bacterial and fungal community abundances and compositions were estimated by real-time PCR and high-throughput amplicon sequencing; then, feedback effects of changes in soil biota on cucumber seedling resistance to FOC were assessed. Moreover, effects of sodium silicate on the growth of FOC and Streptomyces DHV3-2, an antagonistic bacterium to FOC, were investigated both in vitro and in the soil environment. Results showed that exogenous sodium silicate enhanced cucumber seedling growth and resistance to FOC. In bare soil, sodium silicate increased bacterial and fungal community abundances and diversities. In cucumber-cultivated soil, sodium silicate increased bacterial community abundances, but decreased fungal community abundances and diversities. Sodium silicate also changed soil bacterial and fungal communality compositions, and especially, decreased the relative abundances of microbial taxa containing plant pathogens but increased these with plant-beneficial potentials. Moreover, sodium silicate increased the abundance of Streptomyces DHV3-2 in soil. Soil biota from cucumber-cultivated soil treated with sodium silicate decreased cucumber seedling Fusarium wilt disease index, and enhanced cucumber seedling growth and defense-related enzyme activities in roots. Sodium silicate at pH 9.85 inhibited FOC abundance in vitro, but did not affect FOC abundance in soil. Overall, our results suggested that, in cucumber-cultivated soil, sodium silicate increased cucumber seedling

  19. Rhizophagus irregularis MUCL 41833 transitorily reduces tomato bacterial wilt incidence caused by Ralstonia solanacearum under in vitro conditions.

    Science.gov (United States)

    Chave, Marie; Crozilhac, Patrice; Deberdt, Péninna; Plouznikoff, Katia; Declerck, Stéphane

    2017-10-01

    Bacterial wilt caused by Ralstonia solanacearum is one of the world's most important soil-borne plant diseases. In Martinique, French West Indies, a highly virulent new pathogenic variant of this bacterium (phylotype IIB/4NPB) severely impacts tomato production. Here we report on the effect of R. solanacearum CFBP 6783, classified in phytotype IIB/4NPB, on tomato plantlets grown under strict in vitro culture conditions in the presence or absence of the arbuscular mycorrhizal fungus Rhizophagus irregularis MUCL 41833. A mycelium donor plant (i.e. Crotalaria spectabilis) was used for rapid, uniform mycorrhization of tomato plantlets that were subsequently infected by the bacterium. Bacterial wilt was significantly delayed and the incidence of the disease consequently reduced in the mycorrhizal tomato plantlets. Conversely, R. solanacearum did not affect root colonization by the AMF within the 16 days of the experiment. These results suggested that the mycorrhizal fungus was able to reduce bacterial wilt symptoms, probably by eliciting defence mechanisms in the plant.

  20. Comparative efficacy of different fungicides against fusarium wilt of chickpea (cicer arietinum l.)

    International Nuclear Information System (INIS)

    Maitlo, S.A.

    2014-01-01

    Fusarium wilt caused by Fusarium oxysporum f. sp. ciceris (Foc) is the most serious and widespread disease of chickpea, causing a 100% loss under favorable conditions. Fourteen fungicides were evaluated against wilt pathogen In vitro with five different concentrations ranging from 1-10000 ppm. Among these only Carbendazim and Thiophanate-methyl was found as the most effective at all used concentrations. Other fungicides like Aliette, Nativo, Hombre-excel and Dividend star were found to be moderately effective. Whereas, remaining fungicides were ineffective against the targeted pathogen. Generally, a positive co-relation was observed between increasing concentrations of the tested fungicides and inhibition of Foc. Based on In vitro results Carbendazim, Thiophanate-methyl, Aliette, Dividend-star, Hombre-excel, Score and Nativo were selected for pot and field experiments. The higher concentrations of the few fungicides completely inhibited the pathogen as well as found to be phytotoxic and suppressed the plant growth while lower concentrations promoted the growth of chickpea plants. On over all bases, the Carbendazim and Thiophanate-methyl, followed by Aliette and Nativo were more effective in reducing the impact of pathogen as well as enhancing the plant growth in greenhouse experiment. Under field conditions, all fungicides except Score remarkably decreased the disease development and subsequently increased the plant growth as well as grain yield as compared to untreated plants. (author)

  1. Screening of ten advanced chickpea lines for blight and wilt resistance

    International Nuclear Information System (INIS)

    Jamil, F.F.; Haq, I.; Sarwar, N.; Alam, S.S.; Khan, J.A.; Hanif, M.; Khan, I.A.; Sarwar, M.; Haq, M.A.

    2002-01-01

    Ten advanced chickpea lines developed at NIAB were screened for resistance to Ascochyta blight and Fusarium wilt diseases in different sets of experiments conducted under controlled environment. Inoculation of plants by spore suspension of virulent strains of Ascochyta rabiei revealed that one line (97313) was resistant tolerant, two lines (97305, 97392) were tolerant, six lines (97306, 97310, 97311, 97303, 97302, 97393) were tolerant/susceptible and one line (97301) was susceptible. Screening of the same lines against Fusarium wilt by water culture method showed that two lines (97301, 97313) were moderately resistant, four lines (97302, 97303, 97306, 97393) were tolerant and the remaining four lines were susceptible. Screening through phytotoxic culture filtrates revealed that two lines (97302, 97313) were less sensitive to culture filtrates of Ascochyta rabiei and Fusarium oxysporum than the resistant check (CM88). These lines were also analyzed spectrophotometrically for peroxidase enzyme activity. Maximum enzyme activity was detected after 48 hours of inoculation with A. rabiei in three lines (97305, 97311, 97313) and resistant check (CM88) while enzyme activity in the remaining lines reached its maximum after 72 hours of inoculation which was comparable to the susceptible check (Pb-1). These studies lead to the conclusion that one line (97313) exhibited resistance against both the diseases and can be used as a source of resistance for further improvement of chickpea germplasm. (author)

  2. Transgenic tomato hybrids resistant to tomato spotted wilt virus infection.

    NARCIS (Netherlands)

    Haan, de P.; Ultzen, T.; Prins, M.; Gielen, J.; Goldbach, R.; Grinsven, van M.

    1996-01-01

    Tomato spotted wilt virus (TSWV) infections cause significant economic losses in the commercial culture of tomato (Lycopersicon esculentum). Culture practices have only been marginally effective in controlling TSWV. The ultimate way to minimize losses caused by TSWV is resistant varieties. These can

  3. Marker assisted characterization of chickpea genotypes for wilt ...

    African Journals Online (AJOL)

    Further, the sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS PAGE) analysis of seed storage protein showed a difference in protein profile among studied genotypes but none of polypeptide fragment was specific to wilt resistance or susceptibility. In present study, the reported markers linked to susceptibility ...

  4. The origin of Ceratocystis fagacearum, the oak wilt fungus

    Science.gov (United States)

    Jennifer Juzwik; Thomas C. Harrington; William L. MacDonald; David N. Appel

    2008-01-01

    The oak wilt pathogen, Ceratocystis fagacearum, may be another example of a damaging, exotic species in forest ecosystems in the United States. Though C. fagacearum has received much research attention, the origin of the fungus is unknown. The pathogen may have been endemic at a low incidence until increased disturbances, changes...

  5. Evaluation of enset clones against enset bacterial wilt | Welde ...

    African Journals Online (AJOL)

    A large number of enset clones collected from the Sidama, Gurage, Kembata Tembaro and Hadyia zones were assessed for resistance/tolerance to enset bacterial wilt, Xanthomonas campestris pv. musacearum (Xcm) at the Awassa Agricultural Research Center, Awassa in Ethiopia, during the period 1994 to 2000.

  6. Reaction of Musa balbisiana to Banana bacterial wilt infection ...

    African Journals Online (AJOL)

    The expression of NPR1, a marker gene of the systemic acquired resistance plant defence system provides preliminary evidence that this may be the major form of resistance in Musa balbisiana to bacterial wilt infection. Keywords: NPR1, PR proteins, Uganda, Xanthomonas campestris. African Crop Science Journal, Vol.

  7. Integrated management of Fusarium wilt of chickpea (Cicer ...

    African Journals Online (AJOL)

    user

    2013-07-17

    Jul 17, 2013 ... Key words: Integrated management, Fusarium wilt, Fusarium oxysporum f. sp. ciceris, chickpea (Cicer arietinum L.), antagonists, botanicals, fungicides. INTRODUCTION. Chickpea (Cicer arietinum L.) is a vital source of plant- derived edible protein in many countries. Chickpea also has advantages in the ...

  8. The role of NSm during tomato spotted wilt virus infection

    NARCIS (Netherlands)

    Storms, M.M.H.

    1998-01-01

    In the past ten years the genome organisation of tomato spotted wilt virus (TSWV) has been intensively studied in our laboratory. Complete genome sequence data revealed that this enveloped plant virus belongs to the Bunyaviridae, a virus family further restricted to

  9. Integrated management of Fusarium wilt of chickpea ( Cicer ...

    African Journals Online (AJOL)

    The present study was carried out to assess the efficacy of an integrated management strategy for Fusarium wilt of chickpea that combined the use of microbial antagonist, botanical extract and fungicide. Before setting the experiment in field micro plots, a series of in vitro and in vivo experiments were conducted to select a ...

  10. Pollination-Induced Corolla Wilting in Petunia hybrida Rapid Transfer through the Style of a Wilting-Inducing Substance.

    Science.gov (United States)

    Gilissen, L J; Hoekstra, F A

    1984-06-01

    Pollination or wounding of the stigma of Petunia hybrida flowers led to the generation of a wilting factor and its transfer to the corolla within 4 hours. This was concluded from the effects of time course removal of whole styles. In this 4-hour period, pollen tubes traversed only a fraction of the total distance to the ovaries. Both pollination and wounding of the stigma immediately resulted in an increase of ethylene evolution. Accelerated wilting, however, occured only when treated styles remained connected with the ovaries, and not when they were detached and left in the flower. A wilting factor was found in eluates collected from the ovarian end of the styles, only in the case of previous pollination or wounding. In such eluates, the level of the ethylene precursor 1-amino-cyclopropane-1-carboxylic acid was below detection.These observations suggest a material nature of the wilting factor in Petunia flowers, which rapidly passes through the style to the corolla, but which is different from 1-aminocyclopropane-1-carboxylic acid.

  11. Heterologous Expression of the Cotton NBS-LRR Gene GbaNA1 Enhances Verticillium Wilt Resistance in Arabidopsis

    Directory of Open Access Journals (Sweden)

    Nan-Yang Li

    2018-02-01

    Full Text Available Verticillium wilt caused by Verticillium dahliae results in severe losses in cotton, and is economically the most destructive disease of this crop. Improving genetic resistance is the cleanest and least expensive option to manage Verticillium wilt. Previously, we identified the island cotton NBS-LRR-encoding gene GbaNA1 that confers resistance to the highly virulent V. dahliae isolate Vd991. In this study, we expressed cotton GbaNA1 in the heterologous system of Arabidopsis thaliana and investigated the defense response mediated by GbaNA1 following inoculations with V. dahliae. Heterologous expression of GbaNA1 conferred Verticillium wilt resistance in A. thaliana. Moreover, overexpression of GbaNA1 enabled recovery of the resistance phenotype of A. thaliana mutants that had lost the function of GbaNA1 ortholog gene. Investigations of the defense response in A. thaliana showed that the reactive oxygen species (ROS production and the expression of genes associated with the ethylene signaling pathway were enhanced significantly following overexpression of GbaNA1. Intriguingly, overexpression of the GbaNA1 ortholog from Gossypium hirsutum (GhNA1 in A. thaliana did not induce the defense response of ROS production due to the premature termination of GhNA1, which lacks the encoded NB-ARC and LRR motifs. GbaNA1 therefore confers Verticillium wilt resistance in A. thaliana by the activation of ROS production and ethylene signaling. These results demonstrate the functional conservation of the NBS-LRR-encoding GbaNA1 in a heterologous system, and the mechanism of this resistance, both of which may prove valuable in incorporating GbaNA1-mediated resistance into other plant species.

  12. VEGETATIVE COMPATIBILITY GROUPS OF FUSARIUM OXYSPORUM, THE CAUSAL ORGANISM OF VASCULAR WILT ON ROSELLE IN MALAYSIA

    Directory of Open Access Journals (Sweden)

    K.H. Ooi

    1999-01-01

    Full Text Available Forty strains of Fusarium oxysporvm isolated from roselle (Hibiscus sabdariffa var. sabdariffa showing vascular wilt symptoms in three states (Terengganu, Penang and Ipoh in the northern Malaysian Peninsula were used to investigate the vegetative co mpatibility. Nitrate-nonutilizing (nil mutants were recovered from all the strains tested and subsequently used to study vegetative compatibility groups (VCG within the population by nit mutants pairings on minimal medium. Thirteen VCGs were found and none were vegetatively compatible with those of other formae speciales (f. spp. such as asparagi and cubense, and non-pathogenic strains from paddy and oil palm. The results indicate that there is substantial genetic diversity in F. oxysporum that causes vascular wilt disease on roselle as reflected by multiple VCGs, but the distribution of strains into the VCGs is not even as there are 26 representatives in VCG-1001M, two in VCG-1003M and VCG-1013M and only one in the other VCGs. This study may provide new insight into the establishment of a new forma specialis off. oxysporum.

  13. Evaluation of biological control of fusarium wilt in gerbera with Trichoderma asperellum

    Directory of Open Access Journals (Sweden)

    Daiani Brandler

    2017-09-01

    Full Text Available The increase in flower cultivation in recent years has been reflecting the higher incidence of soil pathogens that can cause serious problems. This study aimed to evaluate the biological control of Fusarium wilt in gerbera with Trichoderma asperellum. The evaluated treatments were: T1 Control, only sterile substrate; T2 Substrate + Fusarium oxysporum; T3 Substrate + Fusarium oxysporum + Trichoderma asperellum; and T4 Substrate + Trichoderma asperellum. For this, the pathogen was isolated from gerbera with disease symptoms and, subsequently, it was identified according to morphological characters. Furthermore, the degree of antagonism of T. asperellum against F. oxysporum was evaluated through the culture pairing test. For greenhouse evaluations, commercial autoclaved substrate was used and infested with corn grains infected by the pathogen. Morphological identification confirmed the pathogen species as Fusarium oxysporum. In the culture pairing test, it was found that T. asperellum did not present a high degree of antagonism. The plants cultivated on substrate infested by the pathogen had no visible symptoms of wilt, but the substrate infestation with the pathogen provided lower values of fresh and dry mass of shoots and roots. The treatment with T. asperellum obtained higher values of fresh and dry mass of both shoots and roots, and also more vigorous inflorescences in relation to the plants treated with the pathogen

  14. Marker-assisted selection of Fusarium wilt-resistant and gynoecious melon (Cucumis melo L.).

    Science.gov (United States)

    Gao, P; Liu, S; Zhu, Q L; Luan, F S

    2015-12-08

    In this study, molecular markers were designed based on the sex determination genes ACS7 (A) and WIP1 (G) and the domain in the Fusarium oxysporum-resistant gene Fom-2 (F) in order to achieve selection of F. oxysporum-resistant gynoecious melon plants. Markers of A and F are cleaved amplified polymorphic sequences that distinguish alleles according to restriction analysis. Twenty F1 and 1863 F2 plants derived from the crosses between the gynoecious line WI998 and the Fusarium wilt-resistant line MR-1 were genotyped based on the markers. The results showed that the polymerase chain reaction and enzyme digestion results could be effectively used to identify plants with the AAggFF genotype in F2 populations. In the F2 population, 35 gynoecious wilt-resistant plants were selected by marker-assisted selection and were confirmed by disease infection assays, demonstrating that these markers can be used in breeding to select F. oxysporum-resistant gynoecious melon plants.

  15. Effect of Fertilization on Tomato Bacterial Wilt Biocontrolling and Soil Health Restoration Using FAME Analysis

    Institute of Scientific and Technical Information of China (English)

    CAI Yan-fei; ZHAO Su-qing; LIAO Zong-wen; HE Cheng-xin; ZHUANG Xue-ying

    2003-01-01

    The effect of applying biological organic fertilizer (BOF) on bacterial wilt incidence of tomatoand soil microbial community under continuous cropping was studied. The results showed that all the tomatoeswere infected by bacterial wilt in the control. The infection rates of tomatoes in the treatments with un-com-posted BOF and decomposed BOF were 55 and 50% respectively. Fatty acid methyl esters (FAME) analysisindicated soil microbial community changed sensitively after applying BOF. Soil FAME total content, relativefungi content and ratio of fungi to bacteria were significantly increased in both BOF treatments. The soil odd-number fatty acid proportion changed after applying BOF, aC15: 0, iC17 . 0 decreased, while cyC17 . 0 in-creased in soil odd-number fatty acid proportion. BOF application would strengthen soil health and diseasesuppression. The content of C16: 111c in soil microbial community was obviously increased after decomposedBOF application. It indicated that the growth of AM fungi could be enhanced with decomposed BOF applica-tion. FAME microbial biomarkers could be used for an indicator of soil health and disease suppression. Odd-number fatty acid proportion was a sensitive indicator of the effect of applying un-composted and decomposedBOF respectively on soil health regulating.

  16. Potency of six isolates of biocontrol agents endophytic Trichoderma against fusarium wilt on banana

    Directory of Open Access Journals (Sweden)

    J Taribuka

    2017-01-01

    Full Text Available Fusarium wilt caused by F. oxysporum f.sp. cubense is one of very damaging banana plant diseases which can cause plant death. Disease control using intensive chemical fungicides will have negative impacts on the environment and humans. Endophytic Trichoderma is one of the biological control agents which can reduce the amount of inoculum of pathogens, so it can reduce disease intensity. The objectives of this study was to assess the ability of endophytic Trichoderma in inducing plant resistance against fusarium wilt. Endophytic Trichoderma was obtained from healthy roots of banana from three regencies in Yogyakarta, namely Trichoderma harzianum.swn-1, T. harzianum.swn-2, T. harzianum.psr-1, T. asperrellum, T. gamsii, and T. koningiopsis. Research on induced resintance was conducted in the greenhouse with polybag using Completely Randomized Design with 14 treatments and 3 replications. The results showed that the ability of Trichoderma gamsii antagonism against F. oxysporum f.sp. cubense was 60.61%. T. asperellum and T. harzianum.swn-2 could suppress this disease resulted in disease intensity of 8.33% which categorize as resistant. Trichoderma harzianum.psr-1 was significantly different in stimulating plant vegetative growth. Induced resistance by using endophytic Trichoderma spp. against  F. oxysporum f.sp. cubense showed increase in total phenolic compounds on the third and fourth weeks as well as peroxidase activity on the third, fourth and fifth weeks.  Observation of lignification on  the fifth week  showed that lignification occurred in root xylem

  17. Management of chili pepper root rot and wilt (caused by Phytophthora nicotianae) by grafting onto resistant rootstock

    OpenAIRE

    Mourad SAADOUN; Mohamed Bechir ALLAGUI

    2013-01-01

    Root rot and plant wilting caused by Phytophthora nicotianae is a severe disease of chili pepper (Capsicum annuum L.) in open fields and under greenhouse production in Tunisia. Chili pepper grafting for disease manage- ment is attracting increased interest in recent years. Using the tube grafting technique, different compatible scion/rootstock combinations were obtained with the wild-type pepper SCM334 and the local chili pepper cultivars ‘Beldi’ and ‘Baker’. SCM334 was resistant to P. nicoti...

  18. Phytobiocidal management of bacterial wilt of tomato caused by Ralstonia solanacearum (Smith) Yabuuchi

    Energy Technology Data Exchange (ETDEWEB)

    Din, N.; Ahmad, M.; Siddique, M.; Ali, A.; Naz, I.; Ullah, N.; Ahmad, F.

    2016-11-01

    Phytobiocides are a good alternative to chemicals in managing bacterial diseases including bacterial wilt of tomato caused by Ralstonia solanacearum. In the present research study, finely ground dried powders of seven widely available medicinal plants/weeds species viz., Peganum harmala (esfand or wild rue), Calotropis procera (sodom apple), Melia azedarach (white cedar), Allium sativum (garlic), Adhatoda vasica (malabar nut), Tagetes patula (marigold) and Nerium oleander (oleander) were assessed for their anti-microbial activity, both in-vitro (10% w/v) and in-vivo (10, 20, 30, and 40 g/kg of potted soil) against R. solanacearum. Aqueous extracts (prepared as 10% w/v, soaking for 48-72 h and filtering) of C. procera, A. vasica, and T. patula inhibited the in-vitro growth of the bacterial pathogen over 60% of that produced by the standard antibiotic streptomycin. A. sativum, N. oleander and P. harmala aqueous extracts were less effective while M. azedarach showed no effect against R. solanacearum. The higher dose (40 g/kg of soil) of C. procera, A. vasica and T. patula decreased disease severity quite effectively and increased yield and plant growth characters as much as the standard antibiotic did. No phytotoxicity of medicinal plants powder was observed on tomato plants. Alkaloids, flavonoids, tannins, saponins and terpenoids were detected in the aqueous extracts of T. patula and A. vasica whereas C. procera was found to have only alkaloids, flavonoids, tannins and saponins. Our data suggest that dried powders of T. patula, C. procera and A. vasica (40 g/kg of soil) could be used as an effective component in the integrated disease management programs against bacterial wilt of tomato. (Author)

  19. The Role of the Beetle Hypocryphalus mangiferae (Coleoptera: Curculionidae) in the Spatiotemporal Dynamics of Mango Wilt.

    Science.gov (United States)

    Galdino, Tarcísio Visintin da Silva; Ferreira, Dalton de Oliveira; Santana Júnior, Paulo Antônio; Arcanjo, Lucas de Paulo; Queiroz, Elenir Aparecida; Sarmento, Renato Almeida; Picanço, Marcelo Coutinho

    2017-06-01

    The knowledge of the spatiotemporal dynamics of pathogens and their vectors is an important step in determining the pathogen dispersion pattern and the role of vectors in disease dynamics. However, in the case of mango wilt little is known about its spatiotemporal dynamics and the relationship of its vector [the beetle Hypocryphalus mangiferae (Stebbing 1914)] to these dynamics. The aim of this work was to determine the spatial-seasonal dynamic of H. mangiferae attacks and mango wilt in mango orchards and to verify the importance of H. mangiferae in the spatiotemporal dynamics of the disease. Two mango orchards were monitored during a period of 3 yr. The plants in these orchards were georeferenced and inspected monthly to quantify the number of plants attacked by beetles and the fungus. In these orchards, the percentage of mango trees attacked by beetles was always higher than the percentage infected by the fungus. The colonization of mango trees by beetles and the fungus occurred by colonization of trees both distant and proximal to previously attacked trees. The new plants attacked by the fungus emerged in places where the beetles had previously begun their attack. This phenomenon led to a large overlap in sites of beetle and fungal occurrence, indicating that establishment by the beetle was followed by establishment by the fungus. This information can be used by farmers to predict disease infection, and to control bark beetle infestation in mango orchards. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  20. [Effects of lime-ammonium bicarbonate fumigation and biofertilizer application on Fusarium wilt and biomass of continuous cropping cucumber and watermelon.

    Science.gov (United States)

    Shen, Zong Zhuan; Sun, Li; Wang, Dong Sheng; Lyu, Na Na; Xue, Chao; Li, Rong; Shen, Qi Rong

    2017-10-01

    In this study, the population size of soil microbes was determined using plate counting method after the application of lime-ammonium bicarbonate and ammonium bicarbonate fumigation. In addition, biofertilizer was applied after soil fumigation and population of Fusarium oxysporum, Fusarium wilt disease control efficiency and plant biomass were determined in the cucumber and watermelon continuous cropping soil. The results showed that the population of F. oxysporum in cucumber mono-cropped soil fumigated with lime-ammonium bicarbonate or ammonium bicarbonate was decreased by 95.4% and 71.4%, while that in watermelon mono-cropped soil was decreased by 87.3% and 61.2%, respectively compared with non-fumigated control (CK). Furthermore, the greenhouse experiment showed that biofertilizer application, soil fumigation and crop type showed significant effects on the number of soil F. oxysporum, Fusarium wilt disease incidence, disease control efficiency and plant biomass based on multivariate analysis of variance. In the lime-ammonium bicarbonate fumigated soil amended with biofertilizer (LFB), significant reductions in the numbers of F. oxysporum and Fusarium wilt disease incidence were observed in both cucumber and watermelon cropped soil compared to non-fumigated control soil applied with organic fertilizer. The disease control rate was 91.9% and 92.5% for cucumber and watermelon, respectively. Moreover, LFB also significantly increased the plant height, stem diameter, leaf SPAD, and dry biomass for cucumber and watermelon. It was indicated that biofertilizer application after lime-ammonium bicarbonate fumigation could effectively reduce the abundance of F. oxysporum in soil, control Fusarium wilt disease and improve plant biomass in cucumber and watermelon mono-cropping systems.

  1. The uptake, distribution and translocation of 86Rb in alfalfa plants susceptible and resistant to the bacterial wilt and the effect of Corynebacterium insidiosum upon these processes

    International Nuclear Information System (INIS)

    Hanker, I.; Kudelova, A.

    1981-01-01

    Alfalfa (Medicago sativa L.) plants susceptible (S) and resistant (R) to bacterial wilt were fed via roots with a nutrient solution labelled with 86 Rb + , at different times after inoculation with Corynebacterium insidiosum (McCull.) H.L. Jens. The infection did not affect 86 Rb + uptake per plant in the course of a 14-day-period following inoculation; however, it affected its distribution differently in the S- and the R-plants. 86 Rb + uptake significantly decreased due to the infection in the S-plants on the day 49 after inoculation (a 4-h-exposure to 86 Rb + ), with the ions more slowly translocated to the shoots in diseased S-plants than in diseased R-plants. Likely factors causing these effects and their relationship to alfalfa resistance to bacterial wilt are discussed. (author)

  2. Impact of Laurel Wilt, Caused by Raffaelea lauricola, on Leaf Gas Exchange and Xylem Sap Flow in Avocado, Persea americana.

    Science.gov (United States)

    Ploetz, Randy C; Schaffer, Bruce; Vargas, Ana I; Konkol, Joshua L; Salvatierra, Juanpablo; Wideman, Ronney

    2015-04-01

    Laurel wilt, caused by Raffaelea lauricola, is a destructive disease of avocado (Persea americana). The susceptibility of different cultivars and races was examined previously but more information is needed on how this host responds to the disease. In the present study, net CO2 assimilation (A), stomatal conductance of H2O (gs), transpiration (E), water use efficiency (WUE), and xylem sap flow rates were assessed in cultivars that differed in susceptibility. After artificial inoculation with R. lauricola, there was a close relationship between symptom development and reductions in A, gs, E, WUE, and mean daily sap flow in the most susceptible cultivar, 'Russell', and significantly greater disease and lower A, gs, E, WUE, and sap flow rates were usually detected after 15 days compared with the more tolerant 'Brogdon' and 'Marcus Pumpkin'. Significant differences in preinoculation A, gs, E, and WUE were generally not detected among the cultivars but preinoculation sap flow rates were greater in Russell than in Brogdon and Marcus Pumpkin. Preinoculation sap flow rates and symptom severity for individual trees were correlated at the end of an experiment (r=0.46), indicating that a plant's susceptibility to laurel wilt was related to its ability to conduct water. The potential management of this disease with clonal rootstocks that reduce sap flow rates is discussed.

  3. Comparative Genomics Yields Insights into Niche Adaptation of Plant Vascular Wilt Pathogens

    NARCIS (Netherlands)

    Klosterman, S.J.; Subbarao, K.V.; Kang, S.; Veronese, P.; Gold, S.E.; Thomma, B.P.H.J.; Chen, Z.J.; Henrissat, B.; Lee, Y.H.; Park, J.; Garcia-Pedrajas, M.D.; Barbara, D.J.; Anchieta, A.; Jonge, de R.; Santhanam, P.; Maruthachalam, K.; Atallah, Z.; Amyotte, S.G.; Paz, Z.; Inderbitzin, P.; Hayes, R.J.; Heiman, D.I.; Young, S.; Zeng, Q.; Engels, R.; Galagan, J.; Cuomo, C.; Dobinson, K.F.; Ma, L.J.

    2011-01-01

    The vascular wilt fungi Verticillium dahliae and V. albo-atrum infect over 200 plant species, causing billions of dollars in annual crop losses. The characteristic wilt symptoms are a result of colonization and proliferation of the pathogens in the xylem vessels, which undergo fluctuations in

  4. First report of laurel wilt, caused by Raffaelea lauricola, on sassafras (Sassafras albidum) in Alabama

    Science.gov (United States)

    C.A. Bates; Stephen Fraedrich; T.C. Harrington; R.S. Cameron; R.D. Menard; Susan Best

    2013-01-01

    Laurel wilt, caused by Raffaelea lauricola, a fungal symbiont of the redbay ambrosia beetle, Xyleborus glabratus, is responsible for extensive mortality of native redbays (Persea borbonia and P. Palustris) in the coastal plains of the southeastern United States. The wilt also affect the more...

  5. Molecular and metabolic changes of cherelle wilt of cacao and its effect on Moniliophthora roreri

    Science.gov (United States)

    The seeds of Theobroma cacao L. pods are processed into cocoa products. Cherelle wilt is physiological thinning of young pods that result in loss of potential pods. Cherelle wilt first occurs 50 days after pollination (DAP) and a second thinning occurs around 70 DAP. Cherelles are also highly sus...

  6. Verticillium wilt resistance in Arabidopsis and tomato: identification and functional characterization

    NARCIS (Netherlands)

    Yadeta, K.A.

    2012-01-01

    Vascular wilt pathogens, which comprise bacteria, fungi and oomycetes, are among the most destructive plant pathogens that affect annual crops as well as woody perennials, thus not only impacting world food and feed production but also natural ecosystems. Vascular wilt pathogens colonize the

  7. Environmental Influences on Pigeonpea-Fusarium udum Interactions and Stability of Genotypes to Fusarium Wilt

    Science.gov (United States)

    Sharma, Mamta; Ghosh, Raju; Telangre, Rameshwar; Rathore, Abhishek; Saifulla, Muhammad; Mahalinga, Dayananda M.; Saxena, Deep R.; Jain, Yogendra K.

    2016-01-01

    Fusarium wilt (Fusarium udum Butler) is an important biotic constraint to pigeonpea (Cajanus cajan L.) production worldwide. Breeding for fusarium wilt resistance continues to be an integral part of genetic improvement of pigeonpea. Therefore, the study was aimed at identifying and validating resistant genotypes to fusarium wilt and determining the magnitude of genotype × environment (G × E) interactions through multi-environment and multi-year screening. A total of 976 genotypes including germplasm and breeding lines were screened against wilt using wilt sick plot at Patancheru, India. Ninety two genotypes resistant to wilt were tested for a further two years using wilt sick plot at Patancheru. A Pigeonpea Wilt Nursery (PWN) comprising of 29 genotypes was then established. PWN was evaluated at nine locations representing different agro-climatic zones of India for wilt resistance during two crop seasons 2007/08 and 2008/09. Genotypes (G), environment (E), and G × E interactions were examined by biplot which partitioned the main effect into G, E, and G × E interactions with significant levels (p ≤ 0.001) being obtained for wilt incidence. The genotype contributed 36.51% of resistance variation followed by the environment (29.32%). A GGE biplot integrated with a boxplot and multiple comparison tests enabled us to identify seven stable genotypes (ICPL 20109, ICPL 20096, ICPL 20115, ICPL 20116, ICPL 20102, ICPL 20106, and ICPL 20094) based on their performance across diverse environments. These genotypes have broad based resistance and can be exploited in pigeonpea breeding programs. PMID:27014287

  8. Detailed mapping of a resistance locus against Fusarium wilt in cultivated eggplant (Solanum melongena).

    Science.gov (United States)

    Miyatake, Koji; Saito, Takeo; Negoro, Satomi; Yamaguchi, Hirotaka; Nunome, Tsukasa; Ohyama, Akio; Fukuoka, Hiroyuki

    2016-02-01

    This is the first report on genetic mapping of a resistance locus against Fusarium wilt caused by the plant pathogen Fusarium oxysporum f. sp. melongenae in cultivated eggplant. Fusarium wilt, caused by the plant pathogen Fusarium oxysporum f. sp. melongenae, is a major soil-borne disease threatening stable production in eggplant (Solanum melongena). Although three eggplant germplasms, LS1934, LS174, and LS2436, are known to be highly resistant to the pathogen, their resistance loci have not been mapped. In this study, we performed quantitative trait locus analyses in F2:3 populations and detected a resistance locus, FM1, at the end of chromosome 2, with two alleles, Fm1(L) and Fm1(E), in the F2 populations LWF2 [LS1934 × WCGR112-8 (susceptible)] and EWF2 [EPL-1 (derived from LS174) × WCGR112-8], respectively. The percentage of phenotypic variance explained by Fm1(L) derived from LS1934 was 75.0% [Logarithm of the odds (LOD) = 29.3], and that explained by Fm1(E) derived from EPL-1 was 92.2% (LOD = 65.8). Using backcrossed inbred lines, we mapped FM1 between two simple sequence repeat markers located ~4.881 cM apart from each other. Comparing the location of the above locus to those of previously reported ones, the resistance locus Rfo-sa1 from an eggplant ally (Solanum aethiopicum gr. Gilo) was mapped very close to FM1, whereas another resistance locus, from LS2436, was mapped to the middle of chromosome 4. This is the first report of mapping of a Fusarium resistance locus in cultivated eggplant. The availability of resistance-linked markers will enable the application of marker-assisted selection to overcome problems posed by self-incompatibility and introduction of negative traits because of linkage drag, and will lead to clear understanding of genetic mechanism of Fusarium resistance.

  9. Identification of a Potential ISR Determinant from Pseudomonas aeruginosa PM12 against Fusarium Wilt in Tomato

    Directory of Open Access Journals (Sweden)

    Sabin Fatima

    2017-05-01

    Full Text Available Biocontrol of plant diseases through induction of systemic resistance is an environmental friendly substitute to chemicals in crop protection measures. Different biotic and abiotic elicitors can trigger the plant for induced resistance. Present study was designed to explore the potential of Pseudomonas aeruginosa PM12 in inducing systemic resistance in tomato against Fusarium wilt. Initially the bioactive compound, responsible for ISR, was separated and identified from extracellular filtrate of P. aeruginosa PM12. After that purification and characterization of the bacterial crude extracts was carried out through a series of organic solvents. The fractions exhibiting ISR activity were further divided into sub-fractions through column chromatography. Sub fraction showing maximum ISR activity was subjected to Gas chromatography/mass spectrometry for the identification of compounds. Analytical result showed three compounds in the ISR active sub-fraction viz: 3-hydroxy-5-methoxy benzene methanol (HMB, eugenol and tyrosine. Subsequent bioassays proved that HMB is the potential ISR determinant that significantly ameliorated Fusarium wilt of tomato when applied as soil drench method at the rate of 10 mM. In the next step of this study, GC-MS analysis was performed to detect changes induced in primary and secondary metabolites of tomato plants by the ISR determinant. Plants were treated with HMB and Fusarium oxysporum in different combinations showing intensive re- modulations in defense related pathways. This work concludes that HMB is the potential elicitor involved in dynamic reprogramming of plant pathways which functionally contributes in defense responses. Furthermore the use of biocontrol agents as natural enemies of soil borne pathogens besides enhancing production potential of crop can provide a complementary tactic for sustainable integrated pest management.

  10. Temporal impact of the vascular wilt pathogen Verticillium dahliae on tomato root proteome.

    Science.gov (United States)

    Witzel, Katja; Buhtz, Anja; Grosch, Rita

    2017-10-03

    The soil-borne fungus Verticillium dahliae is the causal agent of wilting disease and affects a wide range of plant species worldwide. Here, we report on the time-resolved analysis of the tomato root proteome in response to fungal colonization. Tomato (Solanum lycopersicum cv. Hildares) was inoculated with V. dahliae at the two-leaf stage and roots were harvested at 7, 14 and 21 days post inoculation (dpi). In order to identify proteins related to the fungal spread at the different time points, a subsequent proteome analysis by two-dimensional differential gel electrophoresis (2D-DIGE) was conducted on samples from three independent experiments. Hierarchical clustering and k-means clustering of identified proteins distinguished early and late responses to fungal colonization. The results underline that plant defense and adaptation responses are timely coordinated. Proteins involved in oxidative stress were down-regulated at 7 dpi but induced 21 dpi indicating versatile reactive oxygen species signaling interacting with salicylic acid defence signaling at that stage of infection. Drought-stress proteins were induced at 21 dpi, reflecting the beginning of wilting symptoms. Notably, two proteins involved in energy-generating pathways were induced throughout all sampling dates and may reflect the increase in metabolic activity to maintain root growth and, concurrently, activate defense responses. Mounting of defense responses requires a substantial flux of carbon and nitrogen from primary to secondary metabolites. In-depth understanding of these key metabolic pathways required for growth and defense responses, especially at proteome level, will allow the development of breeding strategies for crops where Verticillium tolerance is absent. Our data show early and late responses of tomato root proteins towards pathogen infection and identify primary metabolism enzymes affected by V. dahliae. Those proteins represent candidates for plant improvement. Copyright © 2017

  11. Comparisons of the Effects of Elevated Vapor Pressure Deficit on Gene Expression in Leaves among Two Fast-Wilting and a Slow-Wilting Soybean.

    Directory of Open Access Journals (Sweden)

    Mura Jyostna Devi

    Full Text Available Limiting the transpiration rate (TR of a plant under high vapor pressure deficit (VPD has the potential to improve crop yield under drought conditions. The effects of elevated VPD on the expression of genes in the leaves of three soybean accessions, Plant Introduction (PI 416937, PI 471938 and Hutcheson (PI 518664 were investigated because these accessions have contrasting responses to VPD changes. Hutcheson, a fast-wilting soybean, and PI 471938, a slow-wilting soybean, respond to increased VPD with a linear increase in TR. TR of the slow-wilting PI 416937 is limited when VPD increases to greater than about 2 kPa. The objective of this study was to identify the response of the transcriptome of these accessions to elevated VPD under well-watered conditions and identify responses that are unique to the slow-wilting accessions. Gene expression analysis in leaves of genotypes PI 471938 and Hutcheson showed that 22 and 1 genes, respectively, were differentially expressed under high VPD. In contrast, there were 944 genes differentially expressed in PI 416937 with the same increase in VPD. The increased alteration of the transcriptome of PI 416937 in response to elevated VPD clearly distinguished it from the other slow-wilting PI 471938 and the fast-wilting Hutcheson. The inventory and analysis of differentially expressed genes in PI 416937 in response to VPD is a foundation for further investigation to extend the current understanding of plant hydraulic conductivity in drought environments.

  12. The in planta transcriptome of Ralstonia solanacearum: conserved physiological and virulence strategies during bacterial wilt of tomato.

    Science.gov (United States)

    Jacobs, Jonathan M; Babujee, Lavanya; Meng, Fanhong; Milling, Annett; Allen, Caitilyn

    2012-01-01

    Plant xylem fluid is considered a nutrient-poor environment, but the bacterial wilt pathogen Ralstonia solanacearum is well adapted to it, growing to 10(8) to 10(9) CFU/g tomato stem. To better understand how R. solanacearum succeeds in this habitat, we analyzed the transcriptomes of two phylogenetically distinct R. solanacearum strains that both wilt tomato, strains UW551 (phylotype II) and GMI1000 (phylotype I). We profiled bacterial gene expression at ~6 × 10(8) CFU/ml in culture or in plant xylem during early tomato bacterial wilt pathogenesis. Despite phylogenetic differences, these two strains expressed their 3,477 common orthologous genes in generally similar patterns, with about 12% of their transcriptomes significantly altered in planta versus in rich medium. Several primary metabolic pathways were highly expressed during pathogenesis. These pathways included sucrose uptake and catabolism, and components of these pathways were encoded by genes in the scrABY cluster. A UW551 scrA mutant was significantly reduced in virulence on resistant and susceptible tomato as well as on potato and the epidemiologically important weed host Solanum dulcamara. Functional scrA contributed to pathogen competitive fitness during colonization of tomato xylem, which contained ~300 µM sucrose. scrA expression was induced by sucrose, but to a much greater degree by growth in planta. Unexpectedly, 45% of the genes directly regulated by HrpB, the transcriptional activator of the type 3 secretion system (T3SS), were upregulated in planta at high cell densities. This result modifies a regulatory model based on bacterial behavior in culture, where this key virulence factor is repressed at high cell densities. The active transcription of these genes in wilting plants suggests that T3SS has a biological role throughout the disease cycle. IMPORTANCE Ralstonia solanacearum is a widespread plant pathogen that causes bacterial wilt disease. It inflicts serious crop losses on tropical

  13. Vinegar residue compost as a growth substrate enhances cucumber resistance against the Fusarium wilt pathogen Fusarium oxysporum by regulating physiological and biochemical responses.

    Science.gov (United States)

    Shi, Lu; Du, Nanshan; Yuan, Yinghui; Shu, Sheng; Sun, Jin; Guo, Shirong

    2016-09-01

    Fusarium wilt caused by the fungus Fusarium oxysporum f. sp. cucumerinum (FOC) is the most severe soil-borne disease attacking cucumber. To assess the positive effects of vinegar residue substrate (VRS) on the growth and incidence of Fusarium wilt on cucumber, we determined the cucumber growth parameters, disease severity, defense-related enzyme and pathogenesis-related (PR) protein activities, and stress-related gene expression levels. In in vitro and pot experiments, we demonstrated the following results: (i) the VRS extract exhibited a higher biocontrol activity than that of peat against FOC, and significantly improved the growth inhibition of FOC, with values of 48.3 %; (ii) in response to a FOC challenge, antioxidant enzymes and the key enzymes of phenylpropanoid metabolic activities, as well as the PR protein activities in the roots of cucumber, were significantly increased. Moreover, the activities of these proteins were higher in VRS than in peat; (iii) the expression levels of stress-related genes (including glu, pal, and ethylene receptor) elicited responses to the pathogens inoculated in cucumber leaves; and (iv) the FOC treatment significantly inhibited the growth of cucumber seedlings. Moreover, all of the growth indices of plants grown in VRS were significantly higher than those grown in peat. These results offer a new strategy to control cucumber Fusarium wilt, by upregulating the activity levels of defense-related enzymes and PR proteins and adjusting gene expression levels. They also provide a theoretical basis for VRS applications.

  14. Effect of Iron Availability on Induction of Systemic Resistance to Fusarium Wilt of Chickpea by Pseudomonas spp.

    Science.gov (United States)

    Saikia, Ratul; Srivastava, Alok K; Singh, Kiran; Arora, Dilip K; Lee, Min-Woong

    2005-03-01

    Selected isolates of Pseudomonas fluorescens (Pf4-92 and PfRsC5) and P. aeruginosa (PaRsG18 and PaRsG27) were examined for growth promotion and induced systemic resistance against Fusarium wilt of chickpea. Significant increase in plant height was observed in Pseudomonas treated plants. However, plant growth was inhibited when isolates of Pseudomonas were used in combination with Fusarium oxysporum f. sp. ciceri (FocRs1). It was also observed that the Pseudomonas spp. was colonized in root of chickpea and significantly suppressed the disease in greenhouse condition. Rock wool bioassay technique was used to study the effect of iron availability on the induction of systemic resistance to Fusarium wilt of chickpea mediated by the Pseudomonas spp. All the isolates of Pseudomonas spp. showed greater disease control in the induced systemic resistance (ISR) bioassay when iron availability in the nutrient solution was low. High performance liquid chromatography (HPLC) analysis indicated that all the bacterial isolates produced more salicylic acid (SA) at low iron (10µM EDDHA) than high iron availability (10µFe(3+) EDDHA). Except PaRsG27, all the three isolates produced more pseudobactin at low iron than high iron availability.

  15. The Effects of Fungicide, Soil Fumigant, Bio-Organic Fertilizer and Their Combined Application on Chrysanthemum Fusarium Wilt Controlling, Soil Enzyme Activities and Microbial Properties

    Directory of Open Access Journals (Sweden)

    Shuang Zhao

    2016-04-01

    Full Text Available Sustained monoculture often leads to a decline in soil quality, in particular to the build-up of pathogen populations, a problem that is conventionally addressed by the use of either fungicide and/or soil fumigation. This practice is no longer considered to be either environmentally sustainable or safe. While the application of organic fertilizer is seen as a means of combating declining soil fertility, it has also been suggested as providing some control over certain soil-borne plant pathogens. Here, a greenhouse comparison was made of the Fusarium wilt control efficacy of various treatments given to a soil in which chrysanthemum had been produced continuously for many years. The treatments comprised the fungicide carbendazim (MBC, the soil fumigant dazomet (DAZ, the incorporation of a Paenibacillus polymyxa SQR21 (P. polymyxa SQR21, fungal antagonist enhanced bio-organic fertilizer (BOF, and applications of BOF combined with either MBC or DAZ. Data suggest that all the treatments evaluated show good control over Fusarium wilt. The MBC and DAZ treatments were effective in suppressing the disease, but led to significant decrease in urease activity and no enhancement of catalase activity in the rhizosphere soils. BOF including treatments showed significant enhancement in soil enzyme activities and microbial communities compared to the MBC and DAZ, evidenced by differences in bacterial/fungi (B/F ratios, Shannon–Wiener indexes and urease, catalase and sucrase activities in the rhizosphere soil of chrysanthemum. Of all the treatments evaluated, DAZ/BOF application not only greatly suppressed Fusarium wilt and enhanced soil enzyme activities and microbial communities but also promoted the quality of chrysanthemum obviously. Our findings suggest that combined BOF with DAZ could more effectively control Fusarium wilt disease of chrysanthemum.

  16. The endophyte Verticillium Vt305 protects cauliflower against Verticillium wilt.

    Science.gov (United States)

    Tyvaert, L; França, S C; Debode, J; Höfte, M

    2014-06-01

    To investigate the interaction between cauliflower and the isolate VerticilliumVt305, obtained from a field suppressive to Verticillium wilt of cauliflower, and to evaluate the ability of VerticilliumVt305 to control Verticillium wilt of cauliflower caused by V. longisporum. Single and combined inoculations of VerticilliumVt305 and V. longisporum were performed on cauliflower seedlings. Symptom development was evaluated, and fungal colonization was measured in the roots, hypocotyl and stem with real-time PCR. No symptoms were observed after single inoculation of VerticilliumVt305, although it colonized the plant tissues. Pre-inoculation of VerticilliumVt305 reduced symptom development and colonization of plant tissues by V. longisporum. VerticilliumVt305 is an endophyte on cauliflower plants and showed effective biological control of V. longisporum in controlled conditions. This work can contribute to the development of a sustainable control measure of V. longisporum in Brassicaceae hosts, which is currently not available. Additionally, this study provides evidence for the different roles of Verticillium species present in the agro-ecosystem. © 2014 The Society for Applied Microbiology.

  17. Sobre o condicionamento alimentar na cochonilha-branca, Planococcus citri (Risso (Hemiptera: pseudococcidae Regarding to host conditioning in citrus mealybug Planococcus citri (Risso (Hemiptera: pseudococcidae

    Directory of Open Access Journals (Sweden)

    Lenira Viana Costa Santa-Cecília

    2013-03-01

    transferência de cochonilhas de qualquer hospedeiro-fonte para cafeeiro ou citros não afetou o tempo de desenvolvimento, fecundidade e mortalidade, porém aquelas criadas e mantidas em abóbora mostraram maior fecundidade quando comparadas com qualquer outro substrato receptor. Conclui-se que a transferência do substrato, seja cafeeiro, seja citros, não influencia significativamente o comportamento alimentar e o desenvolvimento de P. citri, embora possa existir preferência inicial pelo hospedeiro-fonte.Mealybug probing behavior studied by Electrical Penetration Graphs (EPG method showed that either they do not reach the phloem or this is delayed to 9 hours. However, the phloem phase was reached earlier and more frequently when the mealybugs were reared on the same host used for monitoring. This result indicates the presence of host conditioning so far not reported for mealybugs. This study aimed to detect the effect of the previous experience of the citrus mealybug, Planococcus citri (Risso (Hemiptera: Pseudococcidae on host choice, probing behavior and development. The citrus mealybug was reared on coffee (Coffea arabica L., citrus (Citrus sinensis L. and squash (Cucurbita maxima L. whose were named as source hosts, and transferred to coffee or citrus as receptor host plants. The study included choice tests, electrical penetration graphs (EPG and development studies. The choice test between coffee and citrus in the first 72 hours showed that mealybugs reared on coffee showed a preference to settle on coffee. When the source plant was citrus the insects showed a trend, even not significant, to select citrus over coffee. On the other side, those mealybugs taken from a squash culture did not show any preference neither for coffee nor citrus. The probing behavior monitoring showed that the phloem phase, considered important in plant acceptance, was more frequent in coffee plants, regardless using coffee or citrus as source plants. Those insects transferred from squash to

  18. A new mealybug in the genus Pseudococcus Westwood (Hemiptera: Coccomorpha: Pseudococcidae) from North America, with a key to species of Pseudococcus from the New World.

    Science.gov (United States)

    Ellenrieder, Natalia Von; Watson, Gillian

    2016-04-19

    A mealybug species that feeds on Agave spp., Pseudococcus variabilis sp. n. (Hemiptera: Coccomorpha: Pseudococcidae), is described from North America. Its entry into the United States was likely via the horticultural trade on its host plants in the genus Agave (Liliales: Agavaceae). Descriptions and illustrations of the adult female and male, diagnosis from congeners in the New World, and a molecular characterization based on COI are provided, as well as a key to adult females of all Pseudococcus species recorded from the New World.

  19. [Faba bean fusarium wilt (Fusarium oxysporum )control and its mechanism in different wheat varieties and faba bean intercropping system].

    Science.gov (United States)

    Dong, Yan; Dong, Kun; Zheng, Yi; Tang, Li; Yang, Zhi-Xian

    2014-07-01

    Field experiment and hydroponic culture were conducted to investigate effects of three wheat varieties (Yunmai 42, Yunmai 47 and Mianyang 29) and faba bean intercropping on the shoot biomass, disease index of fusarium wilt, functional diversity of microbial community and the amount of Fusarium oxysporum in rhizosphere of faba bean. Contents and components of the soluble sugars, free amino acids and organic acids in the root exudates were also examined. Results showed that, compared with monocropped faba bean, shoot biomass of faba bean significantly increased by 16.6% and 13.4%, disease index of faba bean fusarium wilt significantly decreased by 47.6% and 23.3% as intercropped with Yunmai 42 and Yunmai 47, but no significant differences of both shoot biomass and disease index were found as intercropped with Mianyang 29. Compared with monocropped faba bean, the average well color development (AWCD value) and total utilization ability of carbon sources of faba bean significantly increased, the amount of Fusarium oxysporum of faba bean rhizosphere significantly decreased, and the microbial community structures of faba bean rhizosphere changed as intercropped with YM42 and YM47, while no significant effects as intercropped with MY29. Total contents of soluble sugar, free amino acids and organic acids in root exudates were in the trend of MY29>YM47>YM42. Contents of serine, glutamic, glycine, valine, methionine, phenylalanine, lysine in root exudates of MY29 were significantly higher than that in YM42 and YM47. The arginine was detected only in the root exudates of YM42 and YM47, and leucine was detected only in the root exudates of MY29. Six organic acids of tartaric acid, malic acid, citric acid, succinic acid, fumaric acid, t-aconitic acid were detected in root exudates of MY29 and YM47, and four organic acids of tartaric acid, malic acid, citric acid, fumaric acid were detected in root exudates of YM42. Malic acid content in root exudates of YM47 and MY29 was

  20. Soil Bacterial Community Was Changed after Brassicaceous Seed Meal Application for Suppression of Fusarium Wilt on Pepper

    Directory of Open Access Journals (Sweden)

    Gaidi Ren

    2018-02-01

    Full Text Available Application of Brassicaceous seed meal (BSM is a promising biologically based disease-control practice but BSM could directly and indirectly also affect the non-target bacterial communities, including the beneficial populations. Understanding the bacterial response to BSM at the community level is of great significance for directing plant disease management through the manipulation of resident bacterial communities. Fusarium wilt is a devastating disease on pepper. However, little is known about the response of bacterial communities, especially the rhizosphere bacterial community, to BSM application to soil heavily infested with Fusarium wilt pathogen and cropped with peppers. In this study, a 25-day microcosm incubation of a natural Fusarium wilt pathogen-infested soil supplemented with three BSMs, i.e., Camelina sativa ‘Crantz’ (CAME, Brassica juncea ‘Pacific Gold’ (PG, and a mixture of PG and Sinapis alba cv. ‘IdaGold’ (IG (PG+IG, 1:1 ratio, was performed. Then, a further 35-day pot experiment was established with pepper plants growing in the BSM treated soils. The changes in the bacterial community in the soil after 25 days of incubation and changes in the rhizosphere after an additional 35 days of pepper growth were investigated by 454 pyrosequencing technique. The results show that the application of PG and PG+IG reduced the disease index by 100% and 72.8%, respectively, after 35 days of pepper growth, while the application of CAME did not have an evident suppressive effect. All BSM treatments altered the bacterial community structure and decreased the bacterial richness and diversity after 25 days of incubation, although this effect was weakened after an additional 35 days of pepper growth. At the phylum/class and the genus levels, the changes in specific bacterial populations resulting from the PG and PG+IG treatments, especially the significant increase in Actinobacteria-affiliated Streptomyces and an unclassified genus and

  1. Induced mutation of new cotton lines tolerant to verticillium wilt with improved characters

    International Nuclear Information System (INIS)

    Rastegary, G.; Hoseiny Neghad, Z.

    1998-01-01

    Induction of mutation for genetic variation has been used in crop improvement for many years. The mutant lines can be used either directly or as a new genetic source in cross breeding. In cotton 'eleven' and 'two' mutant varieties as new genetic sources have been evolved directly and indirectly, respectively. One of the major obstacles in cotton production in northern region of Iran, Gorgan and Gonbad (where they are known as the main cultivation area of this crop), is the presence of verticillium wilt fungal disease. Since this fungus is soil-born, and can not be controlled chemically, the most efficient way of combating against the disease is to breed for the tolerance/resistance of the species. For this purpose, a mutation breeding technique was applied using gamma radiation as mutagen. The seeds of four varieties (Shirpan, Tashkand, Bakhtegan, and Sahel) were irradiated after reaching a proper absorbed humidity. The radiation doses of 150 to 350 Gy were applied and the seeds were cultivated in two different locations (Varamin and Kordkuy) as M1 generation. The cotton balls of each individual healthy plant was harvested to attain the seeds of M2 rows. In M2, the plants with different degrees of tolerance to the disease were compared to the selected parents (taking into consideration that the soil was contaminated). The good yielding lines with different level of tolerance were taken up to the 5th generation, yielding 70 lines of superior qualitative and quantitative traits. (author)

  2. Proteomics of Fusarium oxysporum race 1 and race 4 reveals enzymes involved in carbohydrate metabolism and ion transport that might play important roles in banana Fusarium wilt.

    Science.gov (United States)

    Sun, Yong; Yi, Xiaoping; Peng, Ming; Zeng, Huicai; Wang, Dan; Li, Bo; Tong, Zheng; Chang, Lili; Jin, Xiang; Wang, Xuchu

    2014-01-01

    Banana Fusarium wilt is a soil-spread fungal disease caused by Fusarium oxysporum. In China, the main virulence fungi in banana are F. oxysporum race 1 (F1, weak virulence) and race 4 (F4, strong virulence). To date, no proteomic analyses have compared the two races, but the difference in virulence between F1 and F4 might result from their differentially expressed proteins. Here we report the first comparative proteomics of F1 and F4 cultured under various conditions, and finally identify 99 protein species, which represent 59 unique proteins. These proteins are mainly involved in carbohydrate metabolism, post-translational modification, energy production, and inorganic ion transport. Bioinformatics analysis indicated that among the 46 proteins identified from F4 were several enzymes that might be important for virulence. Reverse transcription PCR analysis of the genes for 15 of the 56 proteins revealed that their transcriptional patterns were similar to their protein expression patterns. Taken together, these data suggest that proteins involved in carbohydrate metabolism and ion transport may be important in the pathogenesis of banana Fusarium wilt. Some enzymes such as catalase-peroxidase, galactosidase and chitinase might contribute to the strong virulence of F4. Overexpression or knockout of the genes for the F4-specific proteins will help us to further understand the molecular mechanism of Fusarium-induced banana wilt.

  3. An evaluation of the wilt-causing bacterium Ralstonia solanacearum as a potential biological control agent for the alien Kahili ginger (Hedychium gardnerianum) in Hawaiian forests

    Science.gov (United States)

    1999-01-01

    Kahili ginger (Hedychium gardnerianum) is an invasive weed in tropical forests in Hawaii and elsewhere. Bacterial wilt caused by the ginger strain of Ralstonia(=Pseudomonas) solanacearum systemically infects edible ginger (Zingiber officinale) and ornamental gingers (Hedychium spp.), causing wilt in infected plants. The suitability of R. solanacearum as a biological control agent for kahili ginger was investigated by inoculating seedlings and rooted cuttings of native forest plants, ornamental ginger, and solanaceous species to confirm host specificity. Inoculation via stem injection or root wounding with a bacterial–water suspension was followed by observation for 8 weeks. Inoculations on H. gardnerianum were then carried out in ohia-lehua (Metrosideros polymorpha) wet forests of Hawaii Volcanoes National Park to determine the bacterium's efficacy in the field. No native forest or solanaceous species developed wilt or other symptoms during the study. The bacterium caused limited infection near the inoculation site on H. coronarium, Z. zerumbet, Heliconia latispatha, and Musa sapientum. However, infection did not become systemic in any of these species, and normal growth resumed following appearance of initial symptoms. All inoculated H. gardnerianum plants developed irreversible chlorosis and severe wilting 3–4 weeks following inoculation. Systemic infection also caused death and decay of rhizomes. Most plants were completely dead 16–20 weeks following inoculation. The destructiveness of the ginger strain of R. solanacearum to edible ginger has raised questions regarding its use for biological control. However, because locations of kahili ginger infestations are often remote, the risk of contaminating edible ginger plantings is unlikely. The ability of this bacterium to cause severe disease in H. gardnerianum in the field, together with its lack of virulence in other ginger species, contributes to its potential as a biological control agent.

  4. Evaluation of bio-agent formulations to control Fusarium wilt of tomato

    African Journals Online (AJOL)

    ONOS

    2010-09-06

    Sep 6, 2010 ... studied with emphasis on biological control using fungi or ... mechanisms such as antibiosis, competition, suppression, ... Fusarium wilt pathogen such as Trichoderma harzianum, .... sphere around soil and above plants.

  5. Bioclimatic thresholds, thermal constants and survival of mealybug, Phenacoccus solenopsis (hemiptera: pseudococcidae) in response to constant temperatures on hibiscus.

    Science.gov (United States)

    Sreedevi, Gudapati; Prasad, Yenumula Gerard; Prabhakar, Mathyam; Rao, Gubbala Ramachandra; Vennila, Sengottaiyan; Venkateswarlu, Bandi

    2013-01-01

    Temperature-driven development and survival rates of the mealybug, Phenacoccussolenopsis Tinsley (Hemiptera: Pseudococcidae) were examined at nine constant temperatures (15, 20, 25, 27, 30, 32, 35 and 40°C) on hibiscus (Hibiscusrosa -sinensis L.). Crawlers successfully completed development to adult stage between 15 and 35°C, although their survival was affected at low temperatures. Two linear and four nonlinear models were fitted to describe developmental rates of P. solenopsis as a function of temperature, and for estimating thermal constants and bioclimatic thresholds (lower, optimum and upper temperature thresholds for development: Tmin, Topt and Tmax, respectively). Estimated thresholds between the two linear models were statistically similar. Ikemoto and Takai's linear model permitted testing the equivalence of lower developmental thresholds for life stages of P. solenopsis reared on two hosts, hibiscus and cotton. Thermal constants required for completion of cumulative development of female and male nymphs and for the whole generation were significantly lower on hibiscus (222.2, 237.0, 308.6 degree-days, respectively) compared to cotton. Three nonlinear models performed better in describing the developmental rate for immature instars and cumulative life stages of female and male and for generation based on goodness-of-fit criteria. The simplified β type distribution function estimated Topt values closer to the observed maximum rates. Thermodynamic SSI model indicated no significant differences in the intrinsic optimum temperature estimates for different geographical populations of P. solenopsis. The estimated bioclimatic thresholds and the observed survival rates of P. solenopsis indicate the species to be high-temperature adaptive, and explained the field abundance of P. solenopsis on its host plants.

  6. Bioclimatic Thresholds, Thermal Constants and Survival of Mealybug, Phenacoccus solenopsis (Hemiptera: Pseudococcidae) in Response to Constant Temperatures on Hibiscus

    Science.gov (United States)

    Sreedevi, Gudapati; Prasad, Yenumula Gerard; Prabhakar, Mathyam; Rao, Gubbala Ramachandra; Vennila, Sengottaiyan; Venkateswarlu, Bandi

    2013-01-01

    Temperature-driven development and survival rates of the mealybug, Phenacoccussolenopsis Tinsley (Hemiptera: Pseudococcidae) were examined at nine constant temperatures (15, 20, 25, 27, 30, 32, 35 and 40°C) on hibiscus ( Hibiscus rosa -sinensis L.). Crawlers successfully completed development to adult stage between 15 and 35°C, although their survival was affected at low temperatures. Two linear and four nonlinear models were fitted to describe developmental rates of P . solenopsis as a function of temperature, and for estimating thermal constants and bioclimatic thresholds (lower, optimum and upper temperature thresholds for development: Tmin, Topt and Tmax, respectively). Estimated thresholds between the two linear models were statistically similar. Ikemoto and Takai’s linear model permitted testing the equivalence of lower developmental thresholds for life stages of P . solenopsis reared on two hosts, hibiscus and cotton. Thermal constants required for completion of cumulative development of female and male nymphs and for the whole generation were significantly lower on hibiscus (222.2, 237.0, 308.6 degree-days, respectively) compared to cotton. Three nonlinear models performed better in describing the developmental rate for immature instars and cumulative life stages of female and male and for generation based on goodness-of-fit criteria. The simplified β type distribution function estimated Topt values closer to the observed maximum rates. Thermodynamic SSI model indicated no significant differences in the intrinsic optimum temperature estimates for different geographical populations of P . solenopsis . The estimated bioclimatic thresholds and the observed survival rates of P . solenopsis indicate the species to be high-temperature adaptive, and explained the field abundance of P . solenopsis on its host plants. PMID:24086597

  7. Distribution of Tomato spotted wilt virus in dahlia plants.

    Science.gov (United States)

    Asano, S; Hirayama, Y; Matsushita, Y

    2017-04-01

    Tomato spotted wilt virus (TSWV) causes significant losses in the production of the ornamental plant Dahlia variabilis in Japan. The purpose of this study was to examine the distribution of TSWV in dahlia plants and identify plant parts that can be used in the selection of TSWV-free plants. The distribution of TSWV was investigated using reverse transcriptional polymerase chain reaction (RT-PCR) and tissue blot immunoassay. The detection rate of TSWV in latent infected compound leaves was the highest in the petiole, and it decreased from the veins and rachis to the lamina. The tissue blot immunoassays of the leaflets showed an uneven distribution of TSWV, especially along the edge of the leaf blade. In stems, the detection rate of TSWV was high partway up the stem compared to that in the upper and the lower parts of the stem during the vegetative growth stage. A highly uneven distribution was observed in the bulb. Our results indicated that middle parts of the stem as well as the petioles, rachis, and veins of compound leaves are suitable for detection of TSWV in dahlias. This study is the first to report uneven distribution of TSWV in dahlia plants. In this study, the distribution of Tomato spotted wilt virus (TSWV) in various parts of dahlia plants was investigated for the first time. The distribution of TSWV was uneven in compound leaves, leaflets, stems, and bulbs. The middle parts of the stem or the petiole and leaf veins should be sampled to detect TSWV when selecting healthy plants. © 2017 The Society for Applied Microbiology.

  8. Evaluation of fungicides and biopesticides for the control of fusarium wilt of tomato

    International Nuclear Information System (INIS)

    Akhtar, T.; Iftikhar, Y.

    2017-01-01

    Fusarium wilt is highly destructive soil borne pathogen in tomato. Current study was carried out to evaluate commercially available fungicides and bio-fungicides in-vitro and in-vivo, for their efficacy against Fusarium oxysporum f.sp. lycopersici. Firstly four fungicides were evaluated under laboratory conditions. Three promising fungicides, two biopesticides and Trichoderma harzianum were further applied both in greenhouse and field experiments. During in-vitro studies PDA amended with fungicides with different treatments at the rate 1% almost completely inhibited the growth of Fol with varying degree of success whereas Nativo being the most effective treatment with 98% reduction in growth as compared to control. Nativo significantly reduced the disease incidence (32.75 %) at concentration of 1%. While Poly-beta-hydroxyl-butyric-acid effectively promoted the tomato growth. Maximum reduction in disease (30.14 %) was expressed by Nativo followed by Teagro (25.06 %) under field conditions. Nativo was found to be the most effective fungicide for management of Fol both In vitro and In vivo. Further field evaluations of the fungicides are required. (author)

  9. Evidence of salicylic acid regulatory mechanisms of disease ...

    African Journals Online (AJOL)

    SAM

    2014-07-23

    Jul 23, 2014 ... disease resistance against banana vascular wilt. Fusarium oxysporium f.sp. ... prominent in that Central American country early last century. Cavendish ... Foc is thought to have originated in Asia, and then spread during the ...

  10. Wilting and biological additive effect on in situ degradability and chemical composition of Arachis pintoi cv Belomonte silage

    OpenAIRE

    Rosana Aparecida Possenti; Evaldo Ferrari Júnior; Valdinei Tadeu Paulino; Ivani Pozar Otsuk; Patrícia Brás

    2010-01-01

    The purpose of this work was to evaluate the effect of wilting and biological additive amendment on chemical composition, fermentation and ruminal degradability of Arachis pintoi cv Belmonte silage. The following treatments were analysed: T1- Arachis pintoi cv Belmonte fresh forage; T2 - Arachis pintoi cv Belmonte fresh forage plus bacterial additive added to the forage prior to the ensilage; T3- Arachis pintoi cv Belmonte wilted by the sun for 4 hours; T4- Arachis pintoi cv Belmonte wilted b...

  11. Ex-Ante Economic Impact Assessment of Genetically Modified Banana Resistant to Xanthomonas Wilt in the Great Lakes Region of Africa.

    Science.gov (United States)

    Ainembabazi, John Herbert; Tripathi, Leena; Rusike, Joseph; Abdoulaye, Tahirou; Manyong, Victor

    2015-01-01

    Credible empirical evidence is scanty on the social implications of genetically modified (GM) crops in Africa, especially on vegetatively propagated crops. Little is known about the future success of introducing GM technologies into staple crops such as bananas, which are widely produced and consumed in the Great Lakes Region of Africa (GLA). GM banana has a potential to control the destructive banana Xanthomonas wilt disease. To gain a better understanding of future adoption and consumption of GM banana in the GLA countries which are yet to permit the production of GM crops; specifically, to evaluate the potential economic impacts of GM cultivars resistant to banana Xanthomonas wilt disease. The paper uses data collected from farmers, traders, agricultural extension agents and key informants in the GLA. We analyze the perceptions of the respondents about the adoption and consumption of GM crop. Economic surplus model is used to determine future economic benefits and costs of producing GM banana. On the release of GM banana for commercialization, the expected initial adoption rate ranges from 21 to 70%, while the ceiling adoption rate is up to 100%. Investment in the development of GM banana is economically viable. However, aggregate benefits vary substantially across the target countries ranging from US$ 20 million to 953 million, highest in countries where disease incidence and production losses are high, ranging from 51 to 83% of production. The findings support investment in the development of GM banana resistant to Xanthomonas wilt disease. The main beneficiaries of this technology development are farmers and consumers, although the latter benefit more than the former from reduced prices. Designing a participatory breeding program involving farmers and consumers signifies the successful adoption and consumption of GM banana in the target countries.

  12. Changes induced by Trichoderma harzianum in suppressive compost controlling Fusarium wilt.

    Science.gov (United States)

    Blaya, Josefa; López-Mondéjar, Rubén; Lloret, Eva; Pascual, Jose Antonio; Ros, Margarita

    2013-09-01

    The addition of species of Trichoderma to compost is a widespread technique used to control different plant diseases. The biological control activity of these species is mainly attributable to a combination of several mechanisms of action, which may affect the microbiota involved in the suppressiveness of compost. This study was therefore performed to determine the effect of inoculation of Trichoderma harzianum (T. harzianum) on compost, focusing on bacterial community structure (16S rRNA) and chitinase gene diversity. In addition, the ability of vineyard pruning waste compost, amended (GCTh) or not (GC) with T. harzianum, to suppress Fusarium wilt was evaluated. The addition of T. harzianum resulted in a high relative abundance of certain chitinolytic bacteria as well as in remarkable protection against Fusarium oxysporum comparable to that induced by compost GC. Moreover, variations in the abiotic characteristics of the media, such as pH, C, N and iron levels, were observed. Despite the lower diversity of chitinolytic bacteria found in GCTh, the high relative abundance of Streptomyces spp. may be involved in the suppressiveness of this growing media. The higher degree of compost suppressiveness achieved after the addition of T. harzianum may be due not only to its biocontrol ability, but also to changes promoted in both abiotic and biotic characteristics of the growing media. Copyright © 2013 Elsevier Inc. All rights reserved.

  13. Spore Acquisition and Survival of Ambrosia Beetles Associated with the Laurel Wilt Pathogen in Avocados after Exposure to Entomopathogenic Fungi

    Directory of Open Access Journals (Sweden)

    Pasco B. Avery

    2018-04-01

    Full Text Available Laurel wilt is a disease threatening the avocado industry in Florida. The causative agent of the disease is a fungus vectored by ambrosia beetles that bore into the trees. Until recently, management strategies for the vectors of the laurel wilt fungus relied solely on chemical control and sanitation practices. Beneficial entomopathogenic fungi (EPF are the most common and prevalent natural enemies of pathogen vectors. Laboratory experiments demonstrated that commercial strains of EPF can increase the mortality of the primary vector, Xyleborus glabratus, and potential alternative vectors, Xylosandrus crassiusculus, Xyleborus volvulus and Xyleborus bispinatus (Coleoptera: Curculionidae: Scolytinae. Our study provides baseline data for three formulated commercially-available entomopathogenic fungi used as potential biocontrol agents against X. crassiusculus, X. volvulus and X. bispinatus. The specific objectives were to determine: (1 the mean number of viable spores acquired per beetle species adult after being exposed to formulated fungal products containing different strains of EPF (Isaria fumosorosea, Metarhizium brunneum and Beauveria bassiana; and (2 the median and mean survival times using paper disk bioassays. Prior to being used in experiments, all fungal suspensions were adjusted to 2.4 × 106 viable spores/mL. The number of spores acquired by X. crassiusculus was significantly higher after exposure to B. bassiana, compared to the other fungal treatments. For X. volvulus, the numbers of spores acquired per beetle were significantly different amongst the different fungal treatments, and the sequence of spore acquisition rates on X. volvulus from highest to lowest was I. fumosorosea > M. brunneum > B. bassiana. After X. bispinatus beetles were exposed to the different suspensions, the rates of acquisition of spores per beetle amongst the different fungal treatments were similar. Survival estimates (data pooled across two tests indicated an

  14. Spore Acquisition and Survival of Ambrosia Beetles Associated with the Laurel Wilt Pathogen in Avocados after Exposure to Entomopathogenic Fungi.

    Science.gov (United States)

    Avery, Pasco B; Bojorque, Verónica; Gámez, Cecilia; Duncan, Rita E; Carrillo, Daniel; Cave, Ronald D

    2018-04-25

    Laurel wilt is a disease threatening the avocado industry in Florida. The causative agent of the disease is a fungus vectored by ambrosia beetles that bore into the trees. Until recently, management strategies for the vectors of the laurel wilt fungus relied solely on chemical control and sanitation practices. Beneficial entomopathogenic fungi (EPF) are the most common and prevalent natural enemies of pathogen vectors. Laboratory experiments demonstrated that commercial strains of EPF can increase the mortality of the primary vector, Xyleborus glabratus , and potential alternative vectors, Xylosandrus crassiusculus , Xyleborus volvulus and Xyleborus bispinatus (Coleoptera: Curculionidae: Scolytinae). Our study provides baseline data for three formulated commercially-available entomopathogenic fungi used as potential biocontrol agents against X. crassiusculus , X. volvulus and X. bispinatus. The specific objectives were to determine: (1) the mean number of viable spores acquired per beetle species adult after being exposed to formulated fungal products containing different strains of EPF ( Isaria fumosorosea , Metarhizium brunneum and Beauveria bassiana ); and (2) the median and mean survival times using paper disk bioassays. Prior to being used in experiments, all fungal suspensions were adjusted to 2.4 × 10⁶ viable spores/mL. The number of spores acquired by X. crassiusculus was significantly higher after exposure to B. bassiana , compared to the other fungal treatments. For X. volvulus , the numbers of spores acquired per beetle were significantly different amongst the different fungal treatments, and the sequence of spore acquisition rates on X. volvulus from highest to lowest was I. fumosorosea > M. brunneum > B. bassiana . After X. bispinatus beetles were exposed to the different suspensions, the rates of acquisition of spores per beetle amongst the different fungal treatments were similar. Survival estimates (data pooled across two tests) indicated an

  15. Management of chili pepper root rot and wilt (caused by Phytophthora nicotianae by grafting onto resistant rootstock

    Directory of Open Access Journals (Sweden)

    Mourad SAADOUN

    2013-05-01

    Full Text Available Root rot and plant wilting caused by Phytophthora nicotianae is a severe disease of chili pepper (Capsicum annuum L. in open fields and under greenhouse production in Tunisia. Chili pepper grafting for disease manage- ment is attracting increased interest in recent years. Using the tube grafting technique, different compatible scion/rootstock combinations were obtained with the wild-type pepper SCM334 and the local chili pepper cultivars ‘Beldi’ and ‘Baker’. SCM334 was resistant to P. nicotianae, while the cultivars Beldi and Baker were susceptible. Plant inoculations were performed with P. nicotianae zoospores, and severity of root rot was rated 30 days post- inoculation using a 0 (healthy plant to 5 (dead plant severity score. On SCM334 rootstock and with ‘Beldi’ or ‘Baker’ scions, the intensity of root rot was very low (mean score 0.1–0.2 and plants were healthy. However, with Baker or Beldi rootstocks and SCM334 scions, root rot was severe (mean score 3.1–4.6, leading to high numbers of wilting and dead plants. This severe root rot was similar to that observed on non-grafted plants of ‘Baker’ and ‘Beldi’ inoculated with the pathogen. Under greenhouse conditions, measurements of agronomic characters indicated non-consistent improvement of these features on the scion cultivar when SCM334 was the rootstock. Since plant foliage is not attacked by this pathogen, these results show that susceptible chili pepper scions grafted onto SCM334 rootstocks could be used for root rot management and improvement of pepper yields in P. nicotianae infested soils.

  16. Resistance selection on banana CV. Ambon Kuning Against Fusarium Wilt

    International Nuclear Information System (INIS)

    Sutarto, Ismiyarti; Meldia, Yeni; Jumjunidang

    1998-01-01

    This research was conducted in order to study the occurrence of mutation on irradiated plantlets and their resistance of plants of banana cv. Ambon Kuning against Fusarium wilt. Plantlets of banana cv. Ambon Kuning sized 5 cm were exposed to gamma rays at the doses 5 - 35 Gy intervals, then were subcultured for obtained M 1 V 5 plantlets. More over, the planlets were acclimatized and were planted in the field was already infected by Fasarium (f).culbense (FOC). The result indicated that irradiated plantlets of the doses 20 - 35 Gy were not able to survive up to 6 months after exposing to gamma rays. Abnormalities of M 1 V 5 plantlets originated from irradiated plantlets at the doses 10 and 15 Gy were shown on rossette plantlets with rigid and dark green leaves, and the formation of smooth mass morphologically shaped like calculus. The appearance of plant height and number of suckers of suckers of M 1 V 5 plants in the field was quite various. The number of survival plants after 8 moths planting was 8, 7, 15, and 28, respectively originated from untreated plants and irradiated plantlets at the doses 5, 10, and 15 Gy. After one year planting , only 2 plants were able to survive from irradiated plantlet at the dose 15 Gy. The plants could produce 27 plantlets obtained from culturing their shoot tips. Further study of these plantlets was needed in order create the stability of their resistance to FOC. (author)

  17. Phylogenetic and recombination analysis of tomato spotted wilt virus.

    Directory of Open Access Journals (Sweden)

    Sen Lian

    Full Text Available Tomato spotted wilt virus (TSWV severely damages and reduces the yield of many economically important plants worldwide. In this study, we determined the whole-genome sequences of 10 TSWV isolates recently identified from various regions and hosts in Korea. Phylogenetic analysis of these 10 isolates as well as the three previously sequenced isolates indicated that the 13 Korean TSWV isolates could be divided into two groups reflecting either two different origins or divergences of Korean TSWV isolates. In addition, the complete nucleotide sequences for the 13 Korean TSWV isolates along with previously sequenced TSWV RNA segments from Korea and other countries were subjected to phylogenetic and recombination analysis. The phylogenetic analysis indicated that both the RNA L and RNA M segments of most Korean isolates might have originated in Western Europe and North America but that the RNA S segments for all Korean isolates might have originated in China and Japan. Recombination analysis identified a total of 12 recombination events among all isolates and segments and five recombination events among the 13 Korea isolates; among the five recombinants from Korea, three contained the whole RNA L segment, suggesting reassortment rather than recombination. Our analyses provide evidence that both recombination and reassortment have contributed to the molecular diversity of TSWV.

  18. Association of Effector Six6 with Vascular Wilt Symptoms Caused by Fusarium oxysporum on Soybean.

    Science.gov (United States)

    Lanubile, Alessandra; Ellis, Margaret L; Marocco, Adriano; Munkvold, Gary P

    2016-11-01

    The Fusarium oxysporum species complex (FOSC) is a widely distributed group of fungi that includes both pathogenic and nonpathogenic isolates. In a previous study, isolates within the FOSC collected primarily from soybean were assessed for the presence of 12 fungal effector genes. Although none of the assayed genes was significantly associated with wilt symptoms on soybean, the secreted in xylem 6 (Six6) gene was present only in three isolates, which all produced high levels of vascular wilt on soybean. In the current study, a collection of F. oxysporum isolates from soybean roots and F. oxysporum f. sp. phaseoli isolates from common bean was screened for the presence of the Six6 gene. Interestingly, all isolates for which the Six6 amplicon was generated caused wilt symptoms on soybean, and two-thirds of the isolates showed high levels of aggressiveness, indicating a positive association between the presence of the effector gene Six6 and induction of wilt symptoms. The expression profile of the Six6 gene analyzed by quantitative reverse-transcription polymerase chain reaction revealed an enhanced expression for the isolates that caused more severe wilt symptoms on soybean, as established by the greenhouse assay. These findings suggest the suitability of the Six6 gene as a possible locus for pathogenicity-based molecular diagnostics across the various formae speciales.

  19. Meta-analysis to refine map position and reduce confidence intervals for delayed canopy wilting QTLs in soybean

    Science.gov (United States)

    Slow canopy wilting in soybean has been identified as a potentially beneficial trait for ameliorating drought effects on yield. Previous research identified QTLs for slow wilting from two different bi-parental populations and this information was combined with data from three other populations to id...

  20. Antagonistic Interactions between the African Weaver Ant Oecophylla longinoda and the Parasitoid Anagyrus pseudococci Potentially Limits Suppression of the Invasive Mealybug Rastrococcus iceryoides

    Directory of Open Access Journals (Sweden)

    Chrysantus M. Tanga

    2015-12-01

    Full Text Available The ant Oecophylla longinoda Latreille forms a trophobiotic relationship with the invasive mealybug Rastrococus iceryoides Green and promotes the latter’s infestations to unacceptable levels in the presence of their natural enemies. In this regard, the antagonistic interactions between the ant and the parasitoid Anagyrus pseudococci Girault were assessed under laboratory conditions. The percentage of parasitism of R. iceryoides by A. pseudococci was significantly higher on “ant-excluded” treatments (86.6% ± 1.27% compared to “ant-tended” treatments (51.4% ± 4.13%. The low female-biased sex-ratio observed in the “ant-tended” treatment can be attributed to ants’ interference during the oviposition phase, which disrupted parasitoids’ ability to fertilize eggs. The mean foraging time, host handling time and number of successful oviposition in “ant-excluded” treatment were significantly higher compared to “ant-tended” treatments. When ant workers were allowed access to sterilized sand grains, mummified and unmummified R. iceryoides, they selectively removed the mummified mealybugs, indicating that they recognized the mummies as potential foods (1.2 ± 0.46 to 7.8 ± 1.17 mummies at 10 min intervals for 2 h. Percentage emergence from mummified R. iceryoides removed by the ants was significantly lower compared to emergence from mummies not exposed to ants. Although, host seeking parasitoids frequently evaded attacks, some were killed by the foraging ant workers (2.0 ± 0.38 to 6.0 ± 0.88 at 10 min intervals for 2 h. These results suggest for the first time that the presence of O. longinoda has a detrimental effect on the abundance, reproductive success and possibly oviposition strategy of female parasitoids, which might be a delimiting factor in field conditions if both natural enemies are to be recommended for use within the same agro-ecosystem.

  1. Influence of Integrated Use of Inorganic fertiliser and Organic manures on Bacterial Wilt Incidence (WI) and Tuber Yield in Potato Production Systems in Southern Slopes of Mt. Kenya

    International Nuclear Information System (INIS)

    Mriithi, L.M.

    2002-01-01

    Bacterial wilt (BW) caused by Ralstonia solanacearum is one of the most damaging of potato (Solanum tuberosum L.) in Kenya and worldwide. In Kenya Potato tuber yield losses due to BW infection are estimated at 50-100%. Low soil fertility is also one of the most important constraints limiting potato production in central Kenya highlands. Farmers tackle this problem through use of inorganic fertilisers and organic manures, both of which amend the soil environment to influence bacterial wilt development. Undecomposed organic manures can also introduce the pathogen into a clean field. Between short rains 1999 and 2000, 10 on-farm researcher/farmer-designed and farmer-managed trials were done at Kianjuki catchment in Embu District. The objective was to use farmers' participatory research approach and select the most suitable organic and inorganic fertiliser combination(s) with lowest BWI and acceptable usable tuber yields. And also demonstrate use of some components of integrated disease management methods in reduction of disease incidence and spread. Seven treatments were proposed, presented to the farmers for discussion and the most relevant four were selected for evaluation . A newly released potato variety 'Asante' was planted during the short-rains 1999 and long rains 2000. BWI didn't;t result in significant differences between treatments but the tuber yields were significantly different in short-rains 1999 and 2000. During short-rains 2000, both BWI and tuber yields and unusable tubers differed significantly between treatments. The results confirmed that use of well-decomposed manures or manures from pathogen-free areas can be used in combination with inorganic fertilisers to improve soil fertility and potato tuber yields in smallholder farm without influencing BWI. Use of certified seed tubers in pathogen free fields and following recommendation field sanitation measures, resulted in apparently bacterial wilt free crop

  2. Association Mapping for Fusarium Wilt Resistance in Chinese Asparagus Bean Germplasm

    Directory of Open Access Journals (Sweden)

    Xinyi Wu

    2015-07-01

    Full Text Available Fusarium wilt (FW is an important vascular disease attacking asparagus bean [ (L. Walp. subsp. Sesquipedalis Group] in China. The level and genetic variability of FW resistance in the Chinese asparagus bean germplasm remains elusive. In the current study, FW resistance was assessed across a natural population consisting of 95 asparagus bean and four African cowpea [ (L. Walp. subsp. Unguiculata Group] accessions. The disease index (DI based on the severity of leaf damage (LFD and vascular discoloration (VD varied highly across the population and the highly resistant varieties used for vegetable are very limited. Genome-wide association study identified 11 and seven single nucleotide polymorphisms (SNPs that are associated with LFD and VD traits, respectively. These SNPs were distributed on nine linkage groups of the asparagus bean genome and each accounted for less than 5% of the phenotypic variation. Overall, the nonstandard vegetable (NSV subgene pool harbors favorable alleles in a higher frequency than the standard vegetable (SV subgene pool. Individual NSV-type accessions tend to possess a greater number of favorable alleles than the SV-type ones. A SNP marker 1_0981 was converted to a cleaved amplified polymorphic sequences (CAPS marker to facilitate future breeding. To our knowledge, this is the first report of an association mapping (AM study in asparagus bean. The results obtained suggests that resources for FW resistance is relatively limited in the SV subgene pool; hence, introducing resistant alleles from the NSV accessions into currently leading SV cultivars will be important to improve FW resistance of the latter.

  3. Comparison of the Transcriptomes of Ginger (Zingiber officinale Rosc.) and Mango Ginger (Curcuma amada Roxb.) in Response to the Bacterial Wilt Infection

    Science.gov (United States)

    Prasath, Duraisamy; Karthika, Raveendran; Habeeba, Naduva Thadath; Suraby, Erinjery Jose; Rosana, Ottakandathil Babu; Shaji, Avaroth; Eapen, Santhosh Joseph; Deshpande, Uday; Anandaraj, Muthuswamy

    2014-01-01

    Bacterial wilt in ginger (Zingiber officinale Rosc.) caused by Ralstonia solanacearum is one of the most important production constraints in tropical, sub-tropical and warm temperature regions of the world. Lack of resistant genotype adds constraints to the crop management. However, mango ginger (Curcuma amada Roxb.), which is resistant to R. solanacearum, is a potential donor, if the exact mechanism of resistance is understood. To identify genes involved in resistance to R. solanacearum, we have sequenced the transcriptome from wilt-sensitive ginger and wilt-resistant mango ginger using Illumina sequencing technology. A total of 26387032 and 22268804 paired-end reads were obtained after quality filtering for C. amada and Z. officinale, respectively. A total of 36359 and 32312 assembled transcript sequences were obtained from both the species. The functions of the unigenes cover a diverse set of molecular functions and biological processes, among which we identified a large number of genes associated with resistance to stresses and response to biotic stimuli. Large scale expression profiling showed that many of the disease resistance related genes were expressed more in C. amada. Comparative analysis also identified genes belonging to different pathways of plant defense against biotic stresses that are differentially expressed in either ginger or mango ginger. The identification of many defense related genes differentially expressed provides many insights to the resistance mechanism to R. solanacearum and for studying potential pathways involved in responses to pathogen. Also, several candidate genes that may underline the difference in resistance to R. solanacearum between ginger and mango ginger were identified. Finally, we have developed a web resource, ginger transcriptome database, which provides public access to the data. Our study is among the first to demonstrate the use of Illumina short read sequencing for de novo transcriptome assembly and comparison in

  4. Modified Primers for the Identification of Nonpathogenic Fusarium oxysporum Isolates That Have Biological Control Potential against Fusarium Wilt of Cucumber in Taiwan

    Science.gov (United States)

    Wang, Chaojen; Lin, Yisheng; Lin, Yinghong; Chung, Wenhsin

    2013-01-01

    Previous investigations demonstrated that Fusarium oxysporum (Fo), which is not pathogenic to cucumbers, could serve as a biological control agent for managing Fusarium wilt of cucumber caused by Fo f. sp. cucumerinum (Foc) in Taiwan. However, thus far it has not been possible to separate the populations of pathogenic Fo from the nonpathogenic isolates that have biological control potential through their morphological characteristics. Although these two populations can be distinguished from one another using a bioassay, the work is laborious and time-consuming. In this study, a fragment of the intergenic spacer (IGS) region of ribosomal DNA from an Fo biological control agent, Fo366, was PCR-amplified with published general primers, FIGS11/FIGS12 and sequenced. A new primer, NPIGS-R, which was designed based on the IGS sequence, was paired with the FIGS11 primer. These primers were then evaluated for their specificity to amplify DNA from nonpathogenic Fo isolates that have biological control potential. The results showed that the modified primer pair, FIGS11/NPIGS-R, amplified a 500-bp DNA fragment from five of seven nonpathogenic Fo isolates. These five Fo isolates delayed symptom development of cucumber Fusarium wilt in greenhouse bioassay tests. Seventy-seven Fo isolates were obtained from the soil and plant tissues and then subjected to amplification using the modified primer pair; six samples showed positive amplification. These six isolates did not cause symptoms on cucumber seedlings when grown in peat moss infested with the isolates and delayed disease development when the same plants were subsequently inoculated with a virulent isolate of Foc. Therefore, the modified primer pair may prove useful for the identification of Fo isolates that are nonpathogenic to cucumber which can potentially act as biocontrol agents for Fusarium wilt of cucumber. PMID:23762289

  5. Comparison of the transcriptomes of ginger (Zingiber officinale Rosc.) and mango ginger (Curcuma amada Roxb.) in response to the bacterial wilt infection.

    Science.gov (United States)

    Prasath, Duraisamy; Karthika, Raveendran; Habeeba, Naduva Thadath; Suraby, Erinjery Jose; Rosana, Ottakandathil Babu; Shaji, Avaroth; Eapen, Santhosh Joseph; Deshpande, Uday; Anandaraj, Muthuswamy

    2014-01-01

    Bacterial wilt in ginger (Zingiber officinale Rosc.) caused by Ralstonia solanacearum is one of the most important production constraints in tropical, sub-tropical and warm temperature regions of the world. Lack of resistant genotype adds constraints to the crop management. However, mango ginger (Curcuma amada Roxb.), which is resistant to R. solanacearum, is a potential donor, if the exact mechanism of resistance is understood. To identify genes involved in resistance to R. solanacearum, we have sequenced the transcriptome from wilt-sensitive ginger and wilt-resistant mango ginger using Illumina sequencing technology. A total of 26387032 and 22268804 paired-end reads were obtained after quality filtering for C. amada and Z. officinale, respectively. A total of 36359 and 32312 assembled transcript sequences were obtained from both the species. The functions of the unigenes cover a diverse set of molecular functions and biological processes, among which we identified a large number of genes associated with resistance to stresses and response to biotic stimuli. Large scale expression profiling showed that many of the disease resistance related genes were expressed more in C. amada. Comparative analysis also identified genes belonging to different pathways of plant defense against biotic stresses that are differentially expressed in either ginger or mango ginger. The identification of many defense related genes differentially expressed provides many insights to the resistance mechanism to R. solanacearum and for studying potential pathways involved in responses to pathogen. Also, several candidate genes that may underline the difference in resistance to R. solanacearum between ginger and mango ginger were identified. Finally, we have developed a web resource, ginger transcriptome database, which provides public access to the data. Our study is among the first to demonstrate the use of Illumina short read sequencing for de novo transcriptome assembly and comparison in

  6. Effect of chipping on emergence of the redbay ambrosia beetle (Coleoptera: Curculionidae: Scolytinae) and recovery of the laurel wilt pathogen from infested wood chips.

    Science.gov (United States)

    Spence, D J; Smith, J A; Ploetz, R; Hulcr, J; Stelinski, L L

    2013-10-01

    Significant mortality ofredbay trees (Persea borbonia (L.) Spreng.) in the southeastern United States has been caused by Raffaelea lauricola, T.C. Harr., Fraedrich, & Aghayeva (Harrington et al. 2008), a fungal symbiont of the exotic redbay ambrosia beetle, Xyleborus glabratus, Eichhoff (Fraedrich et al. 2008). This pathogen causes laurel wilt, which is an irreversible disease that can kill mature trees within a few weeks in summer. R. lauricola has been shown to be lethal to most native species of Lauraceae and cultivated avocado (Persea americana Mill.) in the southeastern United States. In this study, we examined the survival of X. glabratus and R. lauricola in wood chips made from infested trees by using a standard tree chipper over a 10-wk period. After 2 wk, 14 X. glabratus were recovered from wood chips, whereas 339 X. glabratus emerged from nonchipped bolts. R. lauricola was not found 2 d postchipping from wood chips, indicating that the pathogen is not likely to survive for long inside wood chips. In contrast, R. lauricola persisted in dead, standing redbay trees for 14 mo. With large volumes of wood, the potential for infested logs to be moved between states or across U.S. borders is significant. Results demonstrated that chipping wood from laurel wilt-killed trees can significantly reduce the number of X. glabratus and limit the persistence of R. lauricola, which is important for sanitation strategies aimed at limiting the spread of this disease.

  7. ''In vitro'' mutation breeding methodology for Fusarium wilt resistance in banana

    International Nuclear Information System (INIS)

    Tulmann Neto, A.; Domingues, E.T.; Mendes, B.M.J.; Ando, A.

    1990-01-01

    Full text: Besides ''in vivo'' methods, the Radiation Genetics Section of CENA/USP is also using ''in vitro'' methods for mutation breeding to obtain resistance to Panama disease caused by Fusarium oxysporum f.sp. cubense in the banana cultivar ''Maca''. A protocol has been established for the ''in vitro'' development of shoot tips, obtained from plants in the field or already cultivated under i n vitro'' conditions. For both cases, only one culture medium was used during all steps of ''in vitro'' cultivation. New buds were formed and these buds grew and developed to form roots. The medium was composed of macro and micro nutrients, with added Morel vitamines, BAP (5 mg/l), saccharose (30 g/l) and agar (6.5 g/l), at pH 5.7. Cultures were allowed to grow in a controlled environment at 27 deg. C and 16 h illumination. Shoot tips which originated from ''in vitro'' plantlets, were cut longitudinally down the middle. This was done to avoid a tendency of regeneration of the original tissue instead of the formation of new lateral buds. To resolve the chimerism resulting when mutagenic treatment is applied to shoot tips, there is a need of vegetative propagation of new lateral buds. Selection can then be done at M 1 V 4 generation. Once the protocol was established, the gamma ray sensitivity was determined. The dose that produced a 50% decrease in the number of new lateral buds was around 40 Gy and this dose will be utilised. The methodology was completed by soil inoculation with Fusarium of young plants 15 cm in height, obtained from ''in vitro'' cultures. After 3 weeks all inoculated plants showed symptoms of wilt, demonstrating the possibility of screening. The method is now being utilised on a large scale in an attempt to induce a resistant mutant. (author)

  8. Colonization of Tomato Root by Antagonistic Bacterial Strains to Fusarium Wilt of Tomato

    Directory of Open Access Journals (Sweden)

    Arif Wibowo

    2005-12-01

    Full Text Available Fusarium wilt of tomato caused by Fusarium oxysporum f.sp. lycopersici (Fol is an important disease in tomato which cause a significant loss of yield in major growing regions of the world. This study examined the ability of bacterial strains antagonistic to F. oxysporum f.sp. lycopersici (H5, H22, H63, H71, Burkholderia cepacia strain 65 and 526 to colonize tomato seedlings and the effect of plant growth. The effect of bacterial population size and air temperature on the bacterial colonization and their spread along the root systems was also assessed.The results of this study showed that the bacterial population at 28°/23° C day/night temperature 14 days after planting was significantly greater than 23°/18° C for 4 of 6 strains tested. Although there was no significant effect of temperature on bacterial population observed in this study, the ability of the baacterial strains to colonize the rhizosphere was significantly different. Three strains (H5, B. cepacia strain 65 and 526 survived well in the rhizosphere and at 4 weeks after planting rhizosphere populations per gram fresh root were not significantly different from those recovered 2 weeks after planting. The largest population of the bacterial inoculants developed in the basal region of the roots and this differed between strains by log10 2.7 cfu/cm root. The bacterial populations in other parts of the root were also strain dependent. Strain H71, for example, was able to colonize the root segments at a high population level. However strain H63 was recovered only in small number in all root segments.

  9. ''In vitro'' mutation breeding methodology for Fusarium wilt resistance in banana

    Energy Technology Data Exchange (ETDEWEB)

    Tulmann Neto, A; Domingues, E T; Mendes, B M.J.; Ando, A [Centre for Nuclear Energy in Agriculture (CENA), Piracicaba, SP. (Brazil)

    1990-07-01

    Full text: Besides ''in vivo'' methods, the Radiation Genetics Section of CENA/USP is also using ''in vitro'' methods for mutation breeding to obtain resistance to Panama disease caused by Fusarium oxysporum f.sp. cubense in the banana cultivar ''Maca''. A protocol has been established for the ''in vitro'' development of shoot tips, obtained from plants in the field or already cultivated under {sup i}n vitro'' conditions. For both cases, only one culture medium was used during all steps of ''in vitro'' cultivation. New buds were formed and these buds grew and developed to form roots. The medium was composed of macro and micro nutrients, with added Morel vitamines, BAP (5 mg/l), saccharose (30 g/l) and agar (6.5 g/l), at pH 5.7. Cultures were allowed to grow in a controlled environment at 27 deg. C and 16 h illumination. Shoot tips which originated from ''in vitro'' plantlets, were cut longitudinally down the middle. This was done to avoid a tendency of regeneration of the original tissue instead of the formation of new lateral buds. To resolve the chimerism resulting when mutagenic treatment is applied to shoot tips, there is a need of vegetative propagation of new lateral buds. Selection can then be done at M{sub 1}V{sub 4} generation. Once the protocol was established, the gamma ray sensitivity was determined. The dose that produced a 50% decrease in the number of new lateral buds was around 40 Gy and this dose will be utilised. The methodology was completed by soil inoculation with Fusarium of young plants 15 cm in height, obtained from ''in vitro'' cultures. After 3 weeks all inoculated plants showed symptoms of wilt, demonstrating the possibility of screening. The method is now being utilised on a large scale in an attempt to induce a resistant mutant. (author)

  10. Arbuscular mycorrhizal fungi (AMF) as bio protector agents against wilt induced by Verticillium spp. in pepper

    Energy Technology Data Exchange (ETDEWEB)

    Goicoechea, N.; Garmendia, I.; Sanchez-Diaz, M.; Aguirreolea, J.

    2010-07-01

    Verticillium dahliae Kleb. is a vascular pathogen that alters water status and growth of pepper plants and causes drastic reductions in yield. Its control is difficult because it can survive in field soil for several years. The application of arbuscular mycorrhizal fungi (AMF) as bio protector agents against V. dahliae is an alternative to the use of chemicals which, in addition, is more respectful with the environment. The establishment of the mutualistic association of plant roots and AMF involves a continuous cellular and molecular dialogue between both symbionts that includes the pre activation of plant defense responses that may enhance the resistance or tolerance of mycorrhizal plants to soil-borne pathogens. Some AMF can improve the resistance of Capsicum annuum L. against V. dahliae. This is especially relevant for pepper cultivars (i.e. cv. Piquillo) that exhibit high susceptibility to this pathogen. Compared with non-mycorrhizal plants, mycorrhizal pepper can exhibit more balanced antioxidant metabolism in leaves along the first month after pathogen inoculation, which may contribute to delay both the development of disease symptoms and the decrease of photosynthesis in Verticillium-inoculated plants with the subsequent benefit for yield. In stems, mycorrhizal pepper show earlier and higher deposition of lignin in xylem vessels than non mycorrhizal plants, even in absence of the pathogen. Moreover, AMF can induce new isoforms of acidic chitinases and superoxide dismutase in roots. Mycorrhizal-specific induction of these enzymatic activities together with enhanced peroxidase and phenylalanine ammonia-lyase in roots may also be involved in the bio protection of Verticillium-induced wilt in pepper by AMF. (Author) 81 refs.

  11. In praise of mealybugs

    Indian Academy of Sciences (India)

    Vani Brahmachari

    2018-04-30

    Apr 30, 2018 ... chromosomes showed fragmentation in male progeny. (figure 2; Brown and ... no genome contribution to the zygote through the sperm, the molecular .... proportion of 6mA reported in DNA from isolated nuclei suggests that it ...

  12. Combined preharvest and postharvest treatments affect rapid leaf wilting in Bouvardia cut flowers

    NARCIS (Netherlands)

    Schouten, Rob E.; Dien, van Luka; Shahin, Arwa; Heimovaara, Sjoukje; Meeteren, van Uulke; Verdonk, Julian C.

    2018-01-01

    Bouvardia is an ornamental shrub, commercially cultivated as flowering stem. Occasionally, negative water balance, which leads to rapid leaf wilting, ends vase life immediately. This work studies the effect of preharvest and postharvest conditions on vase life, water uptake and transpiration.

  13. An appraisal of oak wilt control programs in Pennsylvania and West Virginia

    Science.gov (United States)

    Thomas W. Jones; Thomas W. Jones

    1971-01-01

    Attempts to control oak wilt, ranging from relatively smallscale experiments to statewide programs, have been made in many States. Among the few currently active, those of Pennsylvania and West Virginia are notable for their size and duration. The pest-control organizations of the Pennsylvania Department of Agriculture and the West Virginia Department of Agriculture...

  14. First report of Laurel Wilt caused by Rafffaelea lauricola on sassafras in Mississippi

    Science.gov (United States)

    J.J. Riggins; S.W. Fraedrich; T.C. Harrington

    2011-01-01

    Laurel wilt is caused by the fungus Raffaelea lauricola T.C. Harrin., Aghayeva & Fraedrich and is lethal to redbay (Persea borbonia (L.) Spreng.), sassafras (Sassafras albidum (Nutt.) Nees), and other species in the Lauraceae (1). The fungus is carried by the redbay ambrosia beetle (Xyleborus glabratus Eichh.), which is native to Asia.

  15. First report of laurel wilt, caused by Raffaelea lauricola, on redbay (Persea borbonia) in Texas.

    Science.gov (United States)

    R. D. Menard; S. R. Clarke; Stephen Fraedrich; T. C. Harrington

    2016-01-01

    Laurel wilt, caused by Raffaelea lauricola T.C.Harr., Aghayeva, & Fraedrich, a fungal symbiont of the redbay ambrosia beetle (Xyleborus glabratus Eichhoff), is responsible for extensive mortality of redbay (Persea borbonia (L.) Spreng) and other Lauraceae native to the United States (Fraedrich et al. 2008). The beetle and fungus were introduced into the United...

  16. Characterization of two biologically distinct variants of Tomato spotted wilt virus

    Science.gov (United States)

    Significant economic losses result on a wide range of crops due to infection with Tomato spotted wilt virus (TSWV). In this study, two TSWV isolates, one from basil and a second from tomato, were established in a common plant host. Viral proteins were monitored over time, plant host ranges were comp...

  17. Antagonistic activity of Bacillus subtilis SB1 and its biocontrol effect on tomato bacterial wilt

    Science.gov (United States)

    A potential biocontrol agent of bacterial wilt, Bacillus subtilis SB1, isolated from tomato roots, showed a broad-spectrum of antimicrobial activity in in vitro experiments. It inhibited the growth of many plant pathogens, including Ralstonia solanacearum, Xanthomonas oryzae pv. oryzae, Fusarium ox...

  18. Evaluation of bio-agent formulations to control Fusarium wilt of tomato

    African Journals Online (AJOL)

    ONOS

    2010-09-06

    Sep 6, 2010 ... when compared to prochoraz and inoculated control. It is concluded ... studied with emphasis on biological control using fungi or bacteria to ...... (*and Other Methods). Version 4. Sinauer Associates, Sunderland,. Massachusetts. Yiğit F, Dikilitas M (2007). Control of Fusarium wilt of tomato by combination of ...

  19. Linkage mapping in a watermelon population segregating for fusarium wilt resistance

    Science.gov (United States)

    Leigh K. Hawkins; Fenny Dane; Thomas L. Kubisiak; Billy B. Rhodes; Robert L. Jarret

    2001-01-01

    Isozyme, randomly amplified polymorphic DNA (RAPD), and simple sequence repeats (SSR) markers were used to generate a linkage map in an F2 and F3 watermelon (Citrullus lanatus (Thumb.) Matsum. & Nakai) population derived from a cross between the fusarium wilt (Fusarium oxysporum f....

  20. Occurrence of Tomato spotted wilt virus in Stevia rebaudiana and Solanum tuberosum in Northern Greece

    NARCIS (Netherlands)

    Chatzivassiliou, E.K.; Peters, D.; Lolas, P.

    2007-01-01

    Tomato spotted wilt virus (TSWV) (genus Tospovirus, family Bunyaviridae) was first reported in Greece during 1972 (3) and currently is widespread in the central and northern part of the country infecting several cultivated and wild plant species (1,2). In June 2006, virus-like symptoms similar to

  1. Genetic diversity, virulence, and Meloidogyne incognita interactions of Fusarium oxysporum isolates causing cotton wilt in Georgia

    Science.gov (United States)

    Locally severe outbreaks of Fusarium wilt of cotton (Gossypium spp.) in South Georgia raised concerns about the genotypes of the causal pathogen, Fusarium oxysporum f. sp. vasinfectum. Vegetative complementation tests and DNA sequence analysis were used to determine genetic diversity among 492 F. ox...

  2. Transmission of tomato spotted wilt tospovirus by Thrips tabaci populations originating from leek

    NARCIS (Netherlands)

    Chatzivassiliou, E.K.; Nagata, T.; Katis, N.I.; Peters, D.

    1999-01-01

    The transmission of tomato spotted wilt tospovirus (TSWV) by Thrips tabaci collected from leek was studied using the petunia local-lesion leaf-disc assay. After an acquisition-access period of 72 h given to newborn larvae up to 8 h old, the efficiency of transmission by adults was determined in

  3. Use of hebicides for control of banana bacterial wilt in Uganda ...

    African Journals Online (AJOL)

    Use of hebicides for control of banana bacterial wilt in Uganda. W Okurut, W K Tushemereirwe, V Aritua, P Ragama. Abstract. No Abstract. African Crop Science Jouranl Vol. 14 (2) 2006: pp. 143-150. Full Text: EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT.

  4. Reduced Bacterial Wilt in Tomato Plants by Bactericidal Peroxyacetic Acid Mixture Treatment

    Directory of Open Access Journals (Sweden)

    Jeum Kyu Hong

    2018-02-01

    Full Text Available Peroxyacetic acid mixture Perosan, composed of peroxyacetic acid, hydrogen peroxide and acetic acid, was evaluated for eco-friendly management of tomato bacterial wilt by Ralstonia pseudosolanacearum. Perosan drastically suppressed in vitro growth of R. pseudosolanacearum in liquid cultures in dose- and incubation time-dependent manners. Higher perosan doses (0.1 and 1% caused lowered pH and phytotoxicity to detached leaves of two tomato cultivars Cupirang and Benekia 220 in aqueous solution. Treatment with 0.01% of Perosan delayed wilting symptom significantly in the detached leaves of two cultivars inoculated with R. pseudosolanacearum (10⁷ cfu/ml. Soil drenching of 5% Perosan solution in pots caused severe tissue collapse of tomato seedlings at the four-week-old stage of two tomato cultivars. Treatment with 1% Perosan by soil-drenching significantly reduced bacterial wilt in the tomato seedlings of two cultivars. These findings suggest that Perosan treatment can be applied to suppress bacterial wilt during tomato production.

  5. Evaluation of Propiconazole Application Methods for Control of Oak Wilt in Texas Live Oaks

    Science.gov (United States)

    A. Dan Wilson; D.G. Lester

    1996-01-01

    Four fungicide application methods using the microencapsulated (blue) 14.3% EC formulation of propiconazole (Alamo), including a low-concentration high volume method, two high-concentration low volume microinjection methods, and a low-concentration intermediate volume soil drench method, were tested for effectiveness in controlling oak wilt in a mature natural stand of...

  6. Polygenic Inheritance of Canopy Wilting in Soybean [Glycine max (L.) Merr.

    Science.gov (United States)

    As water demand for agriculture exceeds water availability, cropping systems need to become more efficient in water usage, such as deployment of cultivars that sustain yield under drought conditions. Soybean cultivars differ in how quickly they wilt during water-deficit stress, and this trait may l...

  7. Aggressiveness of Cephalosporium maydis causing late wilt of maize in Spain.

    Science.gov (United States)

    García-Carneros, A B; Girón, I; Molinero-Ruiz, L

    2012-01-01

    Late wilt of maize, caused by the vascular and soilborne pathogen Cephalosporium maydis, was identified in the Iberian Peninsula in 2008. During the last years the incidence and economical impact of the disease has importantly increased both in Portugal and Spain. Varieties of maize displaying tolerance to the pathogen are available, but the effectiveness can be dependent on the virulence of the fungus (i.e. ability to cause disease on a specific genotype). On the other hand, strains of crop pathogens from different geographic origins can differ with regard to the degree of disease caused on a specific genotype (i.e. aggressiveness). Our working hypothesis was that isolates of C. maydis from different maize growing areas may differ in aggressiveness towards maize plants. Seven fungal strains were isolated in 2009 from diseased plants collected in the most important maize growing regions of Spain and used to inoculate two susceptible maize varieties grown in shadehouse from March to July 2010. The experimental unit consisted of two 4-day-old seedlings planted in an 8-liter pot filled with sand/silt previously infested with 200 g of wheat grains colonized by the fungi. Non colonized wheat grains were used for the control treatments. Six replications (pots) were established for each variety/isolate combination according to a complete randomized 2 x 8 factorial design. The percentage of necrotic and dry aboveground tissues was recorded 14 weeks after inoculation and thereafter weekly until physiological senescence of the control plants. At the end of the experiment, weights of roots and aboveground parts of the plants were recorded. Initial occurrence of symptoms in the plants was significantly dependent on the isolate of C. maydis and on the maize variety. However, final severity of aboveground symptoms (leaf necroses and drying up) was only dependent on the fungal isolate. All the isolates significantly reduced the root weight of both varieties of maize. The highest

  8. Identification of an Endophytic Antifungal Bacterial Strain Isolated from the Rubber Tree and Its Application in the Biological Control of Banana Fusarium Wilt.

    Directory of Open Access Journals (Sweden)

    Deguan Tan

    Full Text Available Banana Fusarium wilt (also known as Panama disease is one of the most disastrous plant diseases. Effective control methods are still under exploring. The endophytic bacterial strain ITBB B5-1 was isolated from the rubber tree, and identified as Serratia marcescens by morphological, biochemical, and phylogenetic analyses. This strain exhibited a high potential for biological control against the banana Fusarium disease. Visual agar plate assay showed that ITBB B5-1 restricted the mycelial growth of the pathogenic fungus Fusarium oxysporum f. sp. cubense race 4 (FOC4. Microscopic observation revealed that the cell wall of the FOC4 mycelium close to the co-cultured bacterium was partially decomposed, and the conidial formation was prohibited. The inhibition ratio of the culture fluid of ITBB B5-1 against the pathogenic fungus was 95.4% as estimated by tip culture assay. Chitinase and glucanase activity was detected in the culture fluid, and the highest activity was obtained at Day 2 and Day 3 of incubation for chitinase and glucanase, respectively. The filtrated cell-free culture fluid degraded the cell wall of FOC4 mycelium. These results indicated that chitinase and glucanase were involved in the antifungal mechanism of ITBB B5-1. The potted banana plants that were inoculated with ITBB B5-1 before infection with FOC4 showed 78.7% reduction in the disease severity index in the green house experiments. In the field trials, ITBB B5-1 showed a control effect of approximately 70.0% against the disease. Therefore, the endophytic bacterial strain ITBB B5-1 could be applied in the biological control of banana Fusarium wilt.

  9. JST Thesaurus Headwords and Synonyms: tomato spotted wilt virus [MeCab user dictionary for science technology term[Archive

    Lifescience Database Archive (English)

    Full Text Available MeCab user dictionary for science technology term tomato spotted wilt virus 名詞 一般 *... * * * トマト黄化壊疽ウイルス トマトオウカエソウイルス トマトーウカエソーイルス Thesaurus2015 200906028155287444 C LS07 UNKNOWN_2 tomato spotted wilt virus

  10. Predictive Models for Tomato Spotted Wilt Virus Spread Dynamics, Considering Frankliniella occidentalis Specific Life Processes as Influenced by the Virus.

    Directory of Open Access Journals (Sweden)

    Pamella Akoth Ogada

    Full Text Available Several models have been studied on predictive epidemics of arthropod vectored plant viruses in an attempt to bring understanding to the complex but specific relationship between the three cornered pathosystem (virus, vector and host plant, as well as their interactions with the environment. A large body of studies mainly focuses on weather based models as management tool for monitoring pests and diseases, with very few incorporating the contribution of vector's life processes in the disease dynamics, which is an essential aspect when mitigating virus incidences in a crop stand. In this study, we hypothesized that the multiplication and spread of tomato spotted wilt virus (TSWV in a crop stand is strongly related to its influences on Frankliniella occidentalis preferential behavior and life expectancy. Model dynamics of important aspects in disease development within TSWV-F. occidentalis-host plant interactions were developed, focusing on F. occidentalis' life processes as influenced by TSWV. The results show that the influence of TSWV on F. occidentalis preferential behaviour leads to an estimated increase in relative acquisition rate of the virus, and up to 33% increase in transmission rate to healthy plants. Also, increased life expectancy; which relates to improved fitness, is dependent on the virus induced preferential behaviour, consequently promoting multiplication and spread of the virus in a crop stand. The development of vector-based models could further help in elucidating the role of tri-trophic interactions in agricultural disease systems. Use of the model to examine the components of the disease process could also boost our understanding on how specific epidemiological characteristics interact to cause diseases in crops. With this level of understanding we can efficiently develop more precise control strategies for the virus and the vector.

  11. Bacterial Diseases of Bananas and Enset: Current State of Knowledge and Integrated Approaches Toward Sustainable Management

    Directory of Open Access Journals (Sweden)

    Guy Blomme

    2017-07-01

    Full Text Available Bacterial diseases of bananas and enset have not received, until recently, an equal amount of attention compared to other major threats to banana production such as the fungal diseases black leaf streak (Mycosphaerella fijiensis and Fusarium wilt (Fusarium oxysporum f. sp. cubense. However, bacteria cause significant impacts on bananas globally and management practices are not always well known or adopted by farmers. Bacterial diseases in bananas and enset can be divided into three groups: (1 Ralstonia-associated diseases (Moko/Bugtok disease caused by Ralstonia solanacearum and banana blood disease caused by R. syzygii subsp. celebesensis; (2 Xanthomonas wilt of banana and enset, caused by Xanthomonas campestris pv. musacearum and (3 Erwinia-associated diseases (bacterial head rot or tip-over disease Erwinia carotovora ssp. carotovora and E. chrysanthemi, bacterial rhizome and pseudostem wet rot (Dickeya paradisiaca formerly E. chrysanthemi pv. paradisiaca. Other bacterial diseases of less widespread importance include: bacterial wilt of abaca, Javanese vascular wilt and bacterial fingertip rot (probably caused by Ralstonia spp., unconfirmed. This review describes global distribution, symptoms, pathogenic diversity, epidemiology and the state of the art for sustainable disease management of the major bacterial wilts currently affecting banana and enset.

  12. In vitro mutation induction for resistance to Fusarium wilt in the banana

    Energy Technology Data Exchange (ETDEWEB)

    Tulmann Neto, A; Mendes, B M.J.; Latado, R [Centro de Energia Nuclear na Agricultura, Piracicaba, SP (Brazil); Cesar Santos, P dos; Boliani, A [Universidade Estadual Paulista, Ilha Solteira, SP (Brazil). Faculdade de Agronomia

    1995-11-01

    In Brazil, which is one of the world`s principal banana production regions, almost all production is consumed within the country. Consumers show high preference for the cultivar Maca (AAB group). However, it is becoming increasingly difficult to produce bananas of this type because of their high susceptibility to Fusarium wilt, caused by Fusarium oxysporum f. sp. cubense. Sexual breeding, which consists of recombination and selection, is limited in the banana because of polyploidy and sterility. Spontaneous somatic mutations are an important source of new cultirvars, and mutation breeding might be particularly important to generate genetic variation. Because of this, the mutation breeding approach has been used in Brazil. The objective of this research was to induce gamma ray mutations for resistance or to increase the level of tolerance to Fusarium wilt in the banana cultivar Maca on the basis of screening under field conditions. 4 refs.

  13. Nucleocapsid Gene-Mediated Transgenic Resistance Provides Protection Against Tomato spotted wilt virus Epidemics in the Field.

    Science.gov (United States)

    Herrero, S; Culbreath, A K; Csinos, A S; Pappu, H R; Rufty, R C; Daub, M E

    2000-02-01

    ABSTRACT Transformation of plants with the nucleocapsid (N) gene of Tomato spotted wilt tospovirus (TSWV) provides resistance to disease development; however, information is lacking on the response of plants to natural inoculum in the field. Three tobacco cultivars were transformed with the N gene of a dahlia isolate of TSWV (TSWV-D), and plants were evaluated over several generations in the greenhouse. The resistant phenotype was more frequently observed in 'Burley 21' than in 'KY-14' or 'K-326', but highly resistant 'Burley 21' transgenic lines were resistant to only 44% of the heterologous TSWV isolates tested. Advanced generation (R(3) and R(4)) transgenic resistant lines of 'Burley 21' and a 'K-326' F(1) hybrid containing the N genes of two TSWV isolates were evaluated in the field near Tifton, GA, where TSWV is endemic. Disease development was monitored by symptom expression and enzyme-linked immunosorbent assay (ELISA) analysis. Whereas incidence of TSWV infection in 'Burley 21' susceptible controls was 20% in 1996 and 62% in 1997, the mean incidence in transgenic lines was reduced to 4 and 31%, respectively. Three transgenic 'Burley 21' lines were identified that had significantly lower incidence of disease than susceptible controls over the two years of the study. In addition, the rate of disease increase at the onset of the 1997 epidemic was reduced for all the 'Burley 21' transgenic lines compared with the susceptible controls. The 'K-326' F(1) hybrid was as susceptible as the 'K-326' nontransformed control. ELISA analysis demonstrated that symptomless plants from the most resistant 'Burley 21' transgenic lines accumulated detectable nucleocapsid protein, whereas symptomless plants from more susceptible lines did not. We conclude that transgenic resistance to TSWV is effective in reducing incidence of the disease in the field, and that accumulation of transgene protein may be important in broad-spectrum resistance.

  14. Evaluation of biological control of fusarium wilt in gerbera with Trichoderma asperellum

    OpenAIRE

    Daiani Brandler; Luan Junior Divensi; Rodrigo José Tonin; Thalita Pedrozo Pilla; Ines Rezendes; Paola Mendes Milanesi

    2017-01-01

    The increase in flower cultivation in recent years has been reflecting the higher incidence of soil pathogens that can cause serious problems. This study aimed to evaluate the biological control of Fusarium wilt in gerbera with Trichoderma asperellum. The evaluated treatments were: T1) Control, only sterile substrate; T2) Substrate + Fusarium oxysporum; T3) Substrate + Fusarium oxysporum + Trichoderma asperellum; and T4) Substrate + Trichoderma asperellum. For this, the pathogen was isolated ...

  15. Identification and Characterization of Wilt and Salt Stress-Responsive MicroRNAs in Chickpea through High-Throughput Sequencing

    Science.gov (United States)

    Deokar, Amit Atmaram; Bhardwaj, Ankur R.; Agarwal, Manu; Katiyar-Agarwal, Surekha; Srinivasan, Ramamurthy; Jain, Pradeep Kumar

    2014-01-01

    Chickpea (Cicer arietinum) is the second most widely grown legume worldwide and is the most important pulse crop in the Indian subcontinent. Chickpea productivity is adversely affected by a large number of biotic and abiotic stresses. MicroRNAs (miRNAs) have been implicated in the regulation of plant responses to several biotic and abiotic stresses. This study is the first attempt to identify chickpea miRNAs that are associated with biotic and abiotic stresses. The wilt infection that is caused by the fungus Fusarium oxysporum f.sp. ciceris is one of the major diseases severely affecting chickpea yields. Of late, increasing soil salinization has become a major problem in realizing these potential yields. Three chickpea libraries using fungal-infected, salt-treated and untreated seedlings were constructed and sequenced using next-generation sequencing technology. A total of 12,135,571 unique reads were obtained. In addition to 122 conserved miRNAs belonging to 25 different families, 59 novel miRNAs along with their star sequences were identified. Four legume-specific miRNAs, including miR5213, miR5232, miR2111 and miR2118, were found in all of the libraries. Poly(A)-based qRT-PCR (Quantitative real-time PCR) was used to validate eleven conserved and five novel miRNAs. miR530 was highly up regulated in response to fungal infection, which targets genes encoding zinc knuckle- and microtubule-associated proteins. Many miRNAs responded in a similar fashion under both biotic and abiotic stresses, indicating the existence of cross talk between the pathways that are involved in regulating these stresses. The potential target genes for the conserved and novel miRNAs were predicted based on sequence homologies. miR166 targets a HD-ZIPIII transcription factor and was validated by 5′ RLM-RACE. This study has identified several conserved and novel miRNAs in the chickpea that are associated with gene regulation following exposure to wilt and salt stress. PMID:25295754

  16. Deep convolutional neural network for classifying Fusarium wilt of radish from unmanned aerial vehicles

    Science.gov (United States)

    Ha, Jin Gwan; Moon, Hyeonjoon; Kwak, Jin Tae; Hassan, Syed Ibrahim; Dang, Minh; Lee, O. New; Park, Han Yong

    2017-10-01

    Recently, unmanned aerial vehicles (UAVs) have gained much attention. In particular, there is a growing interest in utilizing UAVs for agricultural applications such as crop monitoring and management. We propose a computerized system that is capable of detecting Fusarium wilt of radish with high accuracy. The system adopts computer vision and machine learning techniques, including deep learning, to process the images captured by UAVs at low altitudes and to identify the infected radish. The whole radish field is first segmented into three distinctive regions (radish, bare ground, and mulching film) via a softmax classifier and K-means clustering. Then, the identified radish regions are further classified into healthy radish and Fusarium wilt of radish using a deep convolutional neural network (CNN). In identifying radish, bare ground, and mulching film from a radish field, we achieved an accuracy of ≥97.4%. In detecting Fusarium wilt of radish, the CNN obtained an accuracy of 93.3%. It also outperformed the standard machine learning algorithm, obtaining 82.9% accuracy. Therefore, UAVs equipped with computational techniques are promising tools for improving the quality and efficiency of agriculture today.

  17. Biopesticide effect of green compost against fusarium wilt on melon plants.

    Science.gov (United States)

    Ros, M; Hernandez, M T; Garcia, C; Bernal, A; Pascual, J A

    2005-01-01

    The biopesticide effect of four green composts against fusarium wilt in melon plants and the effect of soil quality in soils amended with composts were assayed. The composts consisted of pruning wastes, with or without addition of coffee wastes (3/1 and 4/1, dry wt/dry wt) or urea (1000/1, dry wt/dry wt). In vitro experiments suggested the biopesticide effect of the composts against Fusarium oxysporum, while only the compost of pine bark and urea (1000/1dry wt/dry wt) had an abiotic effect. Melon plant growth with composts and F. oxysporum was one to four times greater than in the non-amended soil, although there was no significant decrease in the level of the F. oxysporum in the soil. The addition of composts to the soil also improved its biological quality, as assessed by microbiological and biochemical parameters: ATP and hydrolases involved in the P (phosphatase), C (beta-glucosidase) and N (urease) cycles. Green composts had greater beneficial characteristics, improved plant growth and controlled fusarium wilt in melon plants. These composts improve the soil quality of semi-arid agricultural soils. Biotic and abiotic factors from composts have been tested as responsible of their biopesticide activity against fusarium wilt.

  18. Species or Genotypes? Reassessment of Four Recently Described Species of the Ceratocystis Wilt Pathogen, Ceratocystis fimbriata, on Mangifera indica.

    Science.gov (United States)

    Oliveira, Leonardo S S; Harrington, Thomas C; Ferreira, Maria A; Damacena, Michelle B; Al-Sadi, Abdullah M; Al-Mahmooli, Issa H S; Alfenas, Acelino C

    2015-09-01

    Ceratocystis wilt is among the most important diseases on mango (Mangifera indica) in Brazil, Oman, and Pakistan. The causal agent was originally identified in Brazil as Ceratocystis fimbriata, which is considered by some as a complex of many cryptic species, and four new species on mango trees were distinguished from C. fimbriata based on variation in internal transcribed spacer sequences. In the present study, phylogenetic analyses using DNA sequences of mating type genes, TEF-1α, and β-tubulin failed to identify lineages corresponding to the four new species names. Further, mating experiments found that the mango isolates representing the new species were interfertile with each other and a tester strain from sweet potato (Ipomoea batatas), on which the name C. fimbriata is based, and there was little morphological variation among the mango isolates. Microsatellite markers found substantial differentiation among mango isolates at the regional and population levels, but certain microsatellite genotypes were commonly found in multiple populations, suggesting that these genotypes had been disseminated in infected nursery stock. The most common microsatellite genotypes corresponded to the four recently named species (C. manginecans, C. acaciivora, C. mangicola, and C. mangivora), which are considered synonyms of C. fimbriata. This study points to the potential problems of naming new species based on introduced genotypes of a pathogen, the value of an understanding of natural variation within and among populations, and the importance of phenotype in delimiting species.

  19. A study of type and intensity of disease infecting banana plants Musa sp at Tegalagung village Semanding subdistrict

    Directory of Open Access Journals (Sweden)

    Supiana Dian Nurtjahyani

    2014-12-01

    Full Text Available Diseases affecting banana plants are very detrimental to farmers as these can lower production and economic income. The purpose of this study was to determine the type and intensity of the disease affecting banana plants. This research was an observational analytic study that observe and analyze condition or symptoms of diseases affecting banana plants in Tegalagung village, Semanding subdistrict, Tuban as many as 38 samples. Parameters observed were type of disease and measure intensity of the disease, data obtained were analyzed descriptively. Based on the symptoms that occurred on the leaves, the study found four disease types affecting banana plant that were fusarium wilt, bacterial wilt (Blood, Sigatoka leaf spot and stunting disease. The diseases intensity were 50% of Fusarium wilt; 26,66% of bacterial wilt (Blood; 26.32% of Sigatoka leaf spot and 15.38% of stunting disease. Conclusion of the study, the highest intensity of the disease that attacks banana plants is Fusarium wilt as high as 50%.

  20. Development of Loop-Mediated Isothermal Amplification (LAMP) assay for rapid detection of Fusarium oxysporum f. sp. ciceris - wilt pathogen of chickpea.

    Science.gov (United States)

    Ghosh, Raju; Nagavardhini, Avuthu; Sengupta, Anindita; Sharma, Mamta

    2015-02-11

    Fusarium oxysporum f. sp. ciceris (Foc), the causal agent of Fusarium wilt is a devastating pathogen of chickpea. In chickpea, various soil borne pathogens produce (s) similar symptoms, therefore cannot be distinguished easily at field level. There is real need for a rapid, inexpensive, and easy to operate and maintain genotyping tool to facilitate accurate disease diagnosis and surveillance for better management of Fusarium wilt outbreaks. In this study, we developed a loop-mediated isothermal amplification (LAMP) assay targeting the elongation factor 1 alpha gene sequence for visual detection of Foc. The LAMP reaction was optimal at 63°C for 60 min. When hydroxynaphthol blue (HNB) was added before amplification, samples with Foc DNA developed a characteristic sky blue colour but those without DNA or with the DNA of six other plant pathogenic fungi did not. Results obtained with LAMP and HNB were confirmed when LAMP products were subjected to gel electrophoresis. The detection limit of this LAMP assay for Foc was 10 fg of genomic DNA per reaction, while that of conventional PCR was 100 pg. In conclusion, it was found that a LAMP assay combined with HNB is simple, rapid, sensitive, and specific. The LAMP assay does not require specialized equipment, hence can be used in the field for the rapid detection of Foc. This is the first report of the use of LAMP assay for the detection of Foc. The presented LAMP method provides a specific, sensitive and rapid diagnostic tool for the distinction of Foc, with the potential to be standardized as a detection method for Foc in endemic areas and will be very useful for monitoring the disease complex in the field further suggesting the management strategies.

  1. Phenotypic evaluation of the resistance in F1 carnation populations to vascular wilt caused by Fusarium oxysporum f.sp. dianthi

    Directory of Open Access Journals (Sweden)

    Johana Carolina Soto-Sedano

    2012-08-01

    Full Text Available One of the most important phytosanitary problems of the carnation crops in Colombia and in the entire world is vascular wilting produced by Fusarium oxysporum f.sp. dianthi. Currently, an effective treatment against the pathogen does not exist; the search for resistant varieties has been the most successful method for control of this disease. Breeding programs are vital to solving the problem of the carnation fusariosis. The objective of this research was the phenotypic evaluation of carnation F1 populations, products of contrasting crossing, resistant per susceptible to F. oxysporum f.sp. dianthi, in order to determine if the resistance is inherited in the lines. This information will contribute to the selection of material and to the successful introduction of the resistant characteristic, whose expression is commercially acceptable, to the gene pool. The methodology adopted was a phenotypic evaluation of the response to the parasite in the population (450 individuals and in the parental. This evaluation estimated the area under the curve (AU DPC, using a scale of symptoms reported for carnation vascular wilt. Three different phenotypes were established with this evaluation. The moderately susceptible one is the predominant phenotype and an analysis of phenotypic frequencies was carried out on it. The results show that the individuals of the evaluated F1 population were distributed between two extreme ranges, resistant and susceptible; this shows that there is segregation for the trait resistant to F. oxysporum f.sp dianthi. We did not observe clearly differentiated classes, i.e. with complete absence or presence of the disease, indicating a possible control of the resistance in the evaluated carnation material, governed by more than one gene and with a possible additive genetic action

  2. Combined effects of biocontrol agents and soil amendments on soil microbial populations, plant growth and incidence of charcoal rot of cowpea and wilt of cumin

    Directory of Open Access Journals (Sweden)

    Vijeta SINGH

    2012-09-01

    Full Text Available Field experiments were conducted for 2 years to determine the effectiveness of combined use of two biocontrol agents, Bacillus firmus and Aspergillus versicolor for control of Macrophomina phaseolina induced charcoal rot of cowpea and Fusarium oxysporum f. sp. cumini induced wilt of cumin. The lowest level of plant mortality (3‒4% due to charcoal rot of cowpea was recorded when bacterium coated seeds were sown in radish compost amended soil compared to the non-amended soil (13.8‒20.5%, but this was not significantly better than some other treatments. Cowpea roots from B. firmus coated seeds had better nodulation than any of the individual A. versicolor treatments. Although B. firmus coated seeds + A. versicolor + farmyard manure resulted in maximum nodulation this was not significantly different to B. firmus seed coating. Root colonization by the combined biocontrol agent treatments was better than the individual biocontrol agent treatments. Combining A. versicolor with farmyard manure supported the maximum populations of total fungi and actinomycetes. In both winter seasons, the lowest incidence of wilt (1.0‒5.2% on cumin was recorded when A. versicolor was amended with neem compost compared to the non-amended soil (5.7‒10.5%. Maximum colonization of A. versicolor on roots was observed in B. firmus + A. versicolor + farmyard manure amended plots. During both years, the treatment combination of A. versicolor in neem compost amended plots resulted in maximum populations of fungi, bacteria and A. versicolor in the soil, which was greater than in the non-amended soil. Significant increases in disease control were not recorded after single or repeated delivery of A. versicolor. These results suggest that combining B. firmus as seed coatings with A. versicolor as soil applications gives improved control of M. phaseolina and Fusarium induced diseases on legume and seed spice crops in arid soils.

  3. Endophytic Bacteria Suppress Bacterial Wilt of Tomato Caused by Ralstonia solanacearum and Activate Defense-related Metabolites

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    Fahime Safdarpour

    2017-12-01

    Full Text Available Introduction: Phytopathogenic microorganisms affect plant health and burden a major threat to food production and ecosystem stability. Increasing the use of chemical pesticides for plant diseases control causes several negative effects on human and environment health. Furthermore, increasing public awareness about the side effects of them led to a research to find alternatives for these products. One of the alternative methods is bio-control utilizing plant associated antagonistic microorganisms. Materials and methods: In this study, 80 endophytic bacteria were isolated from tomato tissues. Their antagonistic activity screened based on agar diffusion test, against tomato bacterial wilt disease (Ralstonia solanacearum. They were identified based on the morphological, biochemical properties and 16s rRNA sequence analyses. These strains were evaluated in greenhouse and tested for their ability to induce the production of defense-related enzymes in plants e.g. Peroxidase (PO, polyphenoloxidase (PPO and phenolics based on spectrophotometer method. Results: Results showed FS67, FS167 and FS184 strains had maximum inhibition zone forming. They identified as Pseudomonas mossellii, P. fuorescence and P. brassicacearum respectively. FS67 and FS167 strains significantly reduced disease in greenhouse. There was a significant increase in the activity of PO, PPO and phenolics in tomato plants treated with FS67, FS167 and pathogen. Discussion and conclusion: The present study has shown that P. mosselli and P. fuorescence might have the potential to control R. solanacearum. However, the good results obtained in vitro cannot be gained the same as those in greenhouse or field conditions. So, further experiments are needed to determine the effectiveness of these isolates under field conditions.This work support the view that increased defense enzymes activities could be involved, at least in part, in the beneficial effects of endophytic bacteria on plants growth

  4. Analysis of Tomato spotted wilt virus NSs protein indicates the importance of the N-terminal for avirulence and RNA silencing suppression

    NARCIS (Netherlands)

    Ronde, de D.; Pasquier, A.; Ying, S.; Butterbach, P.B.E.; Lohuis, D.; Kormelink, R.J.M.

    2014-01-01

    Recently, Tomato spotted wilt virus (TSWV) nonstructural protein NSs has been identified unambiguously as an avirulence (Avr) determinant for Tomato spotted wilt (Tsw)-based resistance. The observation that NSs from two natural resistance-breaking isolates had lost RNA silencing suppressor (RSS)

  5. Diseases threatening banana biodiversity in Uganda ...

    African Journals Online (AJOL)

    Recent on station and on-farm studies suggest the major diseases threatening banana biodiversity in Uganda include: 1)Black sigatoka which severely affects all East African Highland (EA-AAA) banana cultivars and a range of introduced genotypes; 2) Fusarium wilt which affects several introduced genotypes though all EA ...

  6. Potato bacterial wilt management in the Central Highlands of Ethiopia

    African Journals Online (AJOL)

    The purposes of the research was to change the perception of farmers and address the causes, sources and management options of the disease and assist farmers to develop healthy potato farms; Farmers field school(FFS) extension approach supported by sessions harmonized with crop henology was used to assess the ...

  7. Characterization of Verticillium dahliae disease reactions in lettuce differential cultivars

    Science.gov (United States)

    Soilborne diseases significantly affect high value crops in coastal California, including lettuce and strawberry. Breeding crops for pathogen resistance is a strategy for the sustainable management of crop disease. Verticillium dahliae is a soilborne fungus that causes wilt and economic losses in a ...

  8. The distribution and host range of the banana Fusarium wilt fungus, Fusarium oxysporum f. sp. cubense, in Asia.

    Directory of Open Access Journals (Sweden)

    Diane Mostert

    Full Text Available Fusarium oxysporum formae specialis cubense (Foc is a soil-borne fungus that causes Fusarium wilt, which is considered to be the most destructive disease of bananas. The fungus is believed to have evolved with its host in the Indo-Malayan region, and from there it was spread to other banana-growing areas with infected planting material. The diversity and distribution of Foc in Asia was investigated. A total of 594 F. oxysporum isolates collected in ten Asian countries were identified by vegetative compatibility groups (VCGs analysis. To simplify the identification process, the isolates were first divided into DNA lineages using PCR-RFLP analysis. Six lineages and 14 VCGs, representing three Foc races, were identified in this study. The VCG complex 0124/5 was most common in the Indian subcontinent, Vietnam and Cambodia; whereas the VCG complex 01213/16 dominated in the rest of Asia. Sixty-nine F. oxysporum isolates in this study did not match any of the known VCG tester strains. In this study, Foc VCG diversity in Bangladesh, Cambodia and Sri Lanka was determined for the first time and VCGs 01221 and 01222 were first reported from Cambodia and Vietnam. New associations of Foc VCGs and banana cultivars were recorded in all the countries where the fungus was collected. Information obtained in this study could help Asian countries to develop and implement regulatory measures to prevent the incursion of Foc into areas where it does not yet occur. It could also facilitate the deployment of disease resistant banana varieties in infested areas.

  9. The distribution and host range of the banana Fusarium wilt fungus, Fusarium oxysporum f. sp. cubense, in Asia.

    Science.gov (United States)

    Mostert, Diane; Molina, Agustin B; Daniells, Jeff; Fourie, Gerda; Hermanto, Catur; Chao, Chih-Ping; Fabregar, Emily; Sinohin, Vida G; Masdek, Nik; Thangavelu, Raman; Li, Chunyu; Yi, Ganyun; Mostert, Lizel; Viljoen, Altus

    2017-01-01

    Fusarium oxysporum formae specialis cubense (Foc) is a soil-borne fungus that causes Fusarium wilt, which is considered to be the most destructive disease of bananas. The fungus is believed to have evolved with its host in the Indo-Malayan region, and from there it was spread to other banana-growing areas with infected planting material. The diversity and distribution of Foc in Asia was investigated. A total of 594 F. oxysporum isolates collected in ten Asian countries were identified by vegetative compatibility groups (VCGs) analysis. To simplify the identification process, the isolates were first divided into DNA lineages using PCR-RFLP analysis. Six lineages and 14 VCGs, representing three Foc races, were identified in this study. The VCG complex 0124/5 was most common in the Indian subcontinent, Vietnam and Cambodia; whereas the VCG complex 01213/16 dominated in the rest of Asia. Sixty-nine F. oxysporum isolates in this study did not match any of the known VCG tester strains. In this study, Foc VCG diversity in Bangladesh, Cambodia and Sri Lanka was determined for the first time and VCGs 01221 and 01222 were first reported from Cambodia and Vietnam. New associations of Foc VCGs and banana cultivars were recorded in all the countries where the fungus was collected. Information obtained in this study could help Asian countries to develop and implement regulatory measures to prevent the incursion of Foc into areas where it does not yet occur. It could also facilitate the deployment of disease resistant banana varieties in infested areas.

  10. The distribution and host range of the banana Fusarium wilt fungus, Fusarium oxysporum f. sp. cubense, in Asia

    Science.gov (United States)

    Molina, Agustin B.; Daniells, Jeff; Fourie, Gerda; Hermanto, Catur; Chao, Chih-Ping; Fabregar, Emily; Sinohin, Vida G.; Masdek, Nik; Thangavelu, Raman; Li, Chunyu; Yi, Ganyun; Mostert, Lizel; Viljoen, Altus

    2017-01-01

    Fusarium oxysporum formae specialis cubense (Foc) is a soil-borne fungus that causes Fusarium wilt, which is considered to be the most destructive disease of bananas. The fungus is believed to have evolved with its host in the Indo-Malayan region, and from there it was spread to other banana-growing areas with infected planting material. The diversity and distribution of Foc in Asia was investigated. A total of 594 F. oxysporum isolates collected in ten Asian countries were identified by vegetative compatibility groups (VCGs) analysis. To simplify the identification process, the isolates were first divided into DNA lineages using PCR-RFLP analysis. Six lineages and 14 VCGs, representing three Foc races, were identified in this study. The VCG complex 0124/5 was most common in the Indian subcontinent, Vietnam and Cambodia; whereas the VCG complex 01213/16 dominated in the rest of Asia. Sixty-nine F. oxysporum isolates in this study did not match any of the known VCG tester strains. In this study, Foc VCG diversity in Bangladesh, Cambodia and Sri Lanka was determined for the first time and VCGs 01221 and 01222 were first reported from Cambodia and Vietnam. New associations of Foc VCGs and banana cultivars were recorded in all the countries where the fungus was collected. Information obtained in this study could help Asian countries to develop and implement regulatory measures to prevent the incursion of Foc into areas where it does not yet occur. It could also facilitate the deployment of disease resistant banana varieties in infested areas. PMID:28719631

  11. Improvement of Soil Properties, Growth of Cucumber and Protection against Fusarium Wilt by Piriformospora indica and Two Industrial Organic Wastes

    Directory of Open Access Journals (Sweden)

    Moustafa Hemdan Ahmed MOHARAM

    2017-12-01

    Full Text Available The current work was focused on characterizing bagasse ash (BA and press mud (PM as soil amendments and to study their effect in combination with the endophytic fungus Piriformospora indica on Fusarium wilt (FW of cucumber caused by Fusarium oxysporum f. sp. cucumerinum (Fo. Whereas BA and PM improved almost all physico-chemical properties of the soil evaluated, seed treatment with P. indica had no such effect. In shake culture in potato dextrose broth (PDB medium amended with aqueous extracts of BA and PM, alone or in combination, production mycelial mass of Fo was significantly decreased by PM extract, while production mycelial mass of P. indica was highly improved. The colonization rate of cucumber roots by P. indica as determined by microscopy was highly increased by increasing amounts of BA, PM and BA+PM added to the soil. Seed treatment of cucumber with P. indica before plant cultivation in non-amended soil significantly decreased the disease severity of FW and improved plant growth. When seed treated with P. indica was sown into soil amended with BA, PM or the combination of both, the disease severity was even more reduced than after seed treatment with P. indica alone. In this respect, amendment with PM was more effective than with BA, and the combinations were more effective than the single treatments. Hence, there is a scope to integrate PM and BA as soil amendments in combination with P. indica for eco-friendly FW management, improving soil properties and growth of cucumber plants.

  12. Improved horticultural practices against leaf wilting, root rot and nutrient uptake in mango (mangiferaindica l.)

    International Nuclear Information System (INIS)

    Nafees, M.; Ahmad, I.; Ahmad, S.; Anwar, R.; Maryyam, A.; Hussnain, R.R.

    2013-01-01

    Poor plant health condition due to various known biotic and abiotic stresses; becoming a disaster in each mango growing country of the world including Pakistan. On the basis of previous researches on the identification of pathogen and several abiotic factors; Soil drenching and foliar spray of various concentrations of Topsin M (TMIC), Aliette (ATP) and Ridomil Gold (ACE) in combination with CuSO/sub 4/(Copper sulphate) was done on mango plants of cv. S.B. (Samar Bahist) Chaunsa showing wilting of leaves and shoots. Foliar application of micro-nutrients (Fe, B and Zn) (Iron, Boron and Zinc) was also practiced to improve general health of experimental plants Month-wise emergence of flushes was significantly higher in all treated plants compared with control. Percentage of wilted leaves and root rot in plants, which received drenching and foliar treatments, was significantly reduced (50%) compared with untreated plants. Nitrogen, phosphorus and potassium (N, P and K) levels in leaves were significantly improved in treated plants compared with control. Sigmoid relatioship was observed between fungicides and copper sulphate concentrations and uptake of N, P and K in treated plants. Application of 250g ATP fungicide by foliar spray plus 125g by soil drench, each along with 50g CuSO/sub 4/proved to be the best against leaf wilting and it improved the N and P level in leaves. While, application of 250g TMIC by foliar spray and 125g by soil drench, each with 50g CuSO/sub 4/, was found to be the best to reduce the spread of root rot in experimental plants. Preliminary spray of TMIC along with Copper sulphate is effective to improve plant health of mango cv. S.B. Chounsa. (author)

  13. The role of the style as a sense-organ in relation to wilting of the flower.

    Science.gov (United States)

    Gilissen, L J

    1976-01-01

    Pollen tube growth in the style (Petunia ♀xNicotiana ♂) accelerated wilting. Pollination and germination on the stigmatic surface (Petunia ♀xAtropa ♂) did not change the stage of flowering in comparison with unpollinated flowers. Wilting of the corolla was accelerated by cutting off the stigma or cutting the style half-way down. Removal of the entire style also brought about an acceleration, however, to a lesser extent. The role of the style as a sense-organ with regard to the transmission of information from stigma and style to other flower organs is discussed.

  14. The effect of wide swathing on wilting times and nutritive value of alfalfa haylage.

    Science.gov (United States)

    Kung, L; Stough, E C; McDonell, E E; Schmidt, R J; Hofherr, M W; Reich, L J; Klingerman, C M

    2010-04-01

    On 3 consecutive cuttings, alfalfa from a single field was mowed with a John Deere 946 mower-conditioner (4-m cut width; Moline, IL) to leave narrow swaths (NS) ranging from 1.2 to 1.52 m wide (30-37% of cutter bar width) and wide swaths (WS) ranging from 2.44 to 2.74 m wide (62-67% of cutter bar width). Samples were collected from windrows and dry matter (DM) was monitored during wilting until a target of 43 to 45% DM was obtained. Forage from random windrows (n=4-6) was harvested by hand, chopped through a forage harvester before being packed in replicated vacuum-sealed bags, and allowed to ensile for 65 d. There was no swath width x cutting interaction for any parameter tested. Over all cuttings, the resulting silage DM was not different between the NS silage (43.8%) and the WS silage (44.9%). However, wide swathing greatly reduced the time of wilting before making silage. The hours of wilting time needed to reach the targeted DM for the NS silage compared with the WS silage at cuttings 1, 2, and 3 were 50 versus 29, 54 versus 28, and 25 versus 6, respectively. At the time of ensiling, the WS silage had more water-soluble carbohydrates (5.1%) than did the NS silage (3.7%). The WS silage had a lower pH (4.58) than did the NS silage (4.66), but swath width did not affect fermentation end products (lactic acid, acetic acid, and ethanol). The NS silage had more NH(3)-N (0.26%) than did the WS silage (0.21%). Wide swathing did not affect the concentration of ash or the digestibility of NDF, but it lowered the N content (NS=3.45%; WS=3.23%) and increased the ADF content (NS=39.7%; WS=40.9%) of the resulting silage. Wide swathing can markedly reduce the time that alfalfa must wilt before it can be chopped for silage, but under good conditions, as in this study, the resulting silage quality was generally not improved. Copyright (c) 2010 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  15. Identification, transcriptional and functional analysis of heat-shock protein 90s in banana (Musa acuminata L.) highlight their novel role in melatonin-mediated plant response to Fusarium wilt.

    Science.gov (United States)

    Wei, Yunxie; Hu, Wei; Wang, Qiannan; Zeng, Hongqiu; Li, Xiaolin; Yan, Yu; Reiter, Russel J; He, Chaozu; Shi, Haitao

    2017-01-01

    As one popular fresh fruit, banana (Musa acuminata) is cultivated in the world's subtropical and tropical areas. In recent years, pathogen Fusarium oxysporum f. sp. cubense (Foc) has been widely and rapidly spread to banana cultivated areas, causing substantial yield loss. However, the molecular mechanism of banana response to Foc remains unclear, and functional identification of disease-related genes is also very limited. In this study, nine 90 kDa heat-shock proteins (HSP90s) were genomewide identified. Moreover, the expression profile of them in different organs, developmental stages, and in response to abiotic and fungal pathogen Foc were systematically analyzed. Notably, we found that the transcripts of 9 MaHSP90s were commonly regulated by melatonin (N-acetyl-5-methoxytryptamine) and Foc infection. Further studies showed that exogenous application of melatonin improved banana resistance to Fusarium wilt, but the effect was lost when cotreated with HSP90 inhibitor (geldanamycin, GDA). Moreover, melatonin and GDA had opposite effect on auxin level in response to Foc4, while melatonin and GDA cotreated plants had no significant effect, suggesting the involvement of MaHSP90s in the cross talk of melatonin and auxin in response to fungal infection. Taken together, this study demonstrated that MaHSP90s are essential for melatonin-mediated plant response to Fusarium wilt, which extends our understanding the putative roles of MaHSP90s as well as melatonin in the biological control of banana Fusarium wilt. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  16. Successful strategy for the selection of new strawberry-associated rhizobacteria antagonistic to Verticillium wilt.

    Science.gov (United States)

    Berg, G; Kurze, S; Buchner, A; Wellington, E M; Smalla, K

    2000-12-01

    In order to isolate and characterize new strawberry-associated bacteria antagonistic to the soil-borne pathogenic fungus Verticillium dahliae Kleb., rhizobacterial populations from two different strawberry species, Greenish Strawberry (Fragaria viridis) and Garden Strawberry (F. x ananassa) obtained after plating onto King's B and glycerol-arginine agar, were screened for in vitro antagonism toward V. dahliae. The proportion of isolates with antifungal activity determined in in vitro assay against V. dahliae was higher for the Garden Strawberry than for the Greenish Strawberry. From 300 isolates, 20 isolates with strong antifungal activity were selected characterized by physiological profiling and molecular fingerprinting methods. Diversity among the isolates was characterized with molecular fingerprints using amplified ribosomal DNA restriction analysis (ARDRA) and the more discriminating BOX-PCR fingerprint method. The physiological profiles were well correlated with molecular fingerprinting pattern analysis. Significant reduction of Verticillium wilt by bacterial dipping bath treatment was shown in the greenhouse and in fields naturally infested by V. dahliae. The relative increase of yield ranged from 117% (Streptomyces albidoflavus S1) to 344% (Pseudomonas fluorescens P10) in greenhouse trials, and 113% (Streptomyces albidoflavus S1) to 247% (Pseudomonas fluorescens P6) in field trials. Evaluation resulted in the selection of three effective biocontrol agents (Pseudomonas fluorescens P6, P10, and Streptomyces diastatochromogenes S9) antagonistic to the Verticillium wilt pathogen.

  17. Partnerships Between Ambrosia Beetles and Fungi: Lineage-Specific Promiscuity Among Vectors of the Laurel Wilt Pathogen, Raffaelea lauricola.

    Science.gov (United States)

    Saucedo-Carabez, J R; Ploetz, Randy C; Konkol, J L; Carrillo, D; Gazis, R

    2018-04-20

    Nutritional mutualisms that ambrosia beetles have with fungi are poorly understood. Although these interactions were initially thought to be specific associations with a primary symbiont, there is increasing evidence that some of these fungi are associated with, and move among, multiple beetle partners. We examined culturable fungi recovered from mycangia of ambrosia beetles associated with trees of Persea humilis (silk bay, one site) and P. americana (avocado, six commercial orchards) that were affected by laurel wilt, an invasive disease caused by a symbiont, Raffaelea lauricola, of an Asian ambrosia beetle, Xyleborus glabratus. Fungi were isolated from 20 adult females of X. glabratus from silk bay and 70 each of Xyleborus affinis, Xyleborus bispinatus, Xyleborus volvulus, Xyleborinus saxesenii, and Xylosandrus crassiusculus from avocado. With partial sequences of ribosomal (LSU and SSU) and nuclear (β-tubulin) genes, one to several operational taxonomic units (OTUs) of fungi were identified in assayed individuals. Distinct populations of fungi were recovered from each of the examined beetle species. Raffaelea lauricola was present in all beetles except X. saxesenii and X. crassiusculus, and Raffaelea spp. predominated in Xyleborus spp. Raffaelea arxii, R. subalba, and R. subfusca were present in more than a single species of Xyleborus, and R. arxii was the most abundant symbiont in both X. affinis and X. volvulus. Raffaelea aguacate was detected for the first time in an ambrosia beetle (X. bispinatus). Yeasts (Ascomycota, Saccharomycotina) were found consistently in the mycangia of the examined beetles, and distinct, putatively co-adapted populations of these fungi were associated with each beetle species. Greater understandings are needed for how mycangia in ambrosia beetles interact with fungi, including yeasts which play currently underresearched roles in these insects.

  18. Vertical Distribution and Daily Flight Periodicity of Ambrosia Beetles (Coleoptera: Curculionidae) in Florida Avocado Orchards Affected by Laurel Wilt.

    Science.gov (United States)

    Menocal, Octavio; Kendra, Paul E; Montgomery, Wayne S; Crane, Jonathan H; Carrillo, Daniel

    2018-03-08

    Ambrosia beetles have emerged as significant pests of avocado ((Persea americana Mill. [Laurales: Lauraceae])) due to their association with pathogenic fungal symbionts, most notably Raffaelea lauricola T.C. Harr., Fraedrich & Aghayeva (Ophiostomatales: Ophiostomataceae), the causal agent of the laurel wilt (LW) disease. We evaluated the interaction of ambrosia beetles with host avocado trees by documenting their flight height and daily flight periodicity in Florida orchards with LW. Flight height was assessed passively in three avocado orchards by using ladder-like arrays of unbaited sticky traps arranged at three levels (low: 0-2 m; middle: 2-4 m; high: 4-6 m). In total, 1,306 individuals of 12 Scolytinae species were intercepted, but six accounted for ~95% of the captures: Xyleborus volvulus (Fabricius) (Coleoptera: Curculionidae), Xyleborinus saxesenii Ratzeburg (Coleoptera: Curculionidae), Euplatypus parallelus (Fabricius) (Coleoptera: Curculionidae), Xyleborus bispinatus Eichhoff (Coleoptera: Curculionidae), Xyleborus affinis Eichhoff (Coleoptera: Curculionidae), and Hypothenemus sp. (Coleoptera: Curculionidae). The primary vector of R. lauricola, Xyleborus glabratus Eichhoff (Coleoptera: Curculionidae), was not detected. Females of X. volvulus showed a preference for flight at low levels and X. bispinatus for the low and middle levels; however, captures of all other species were comparable at all heights. At a fourth orchard, a baiting method was used to document flight periodicity. Females of X. saxesenii and Hypothenemus sp. were observed in flight 2-2.5 h prior to sunset; X. bispinatus, X. volvulus, and X. affinis initiated flight at ~1 h before sunset and Xylosandrus crassiusculus (Motschulsky) (Coleoptera: Curculionidae) at 30 min prior to sunset. Results suggest that ambrosia beetles in South Florida fly near sunset (when light intensity and wind speed decrease) at much greater heights than previously assumed and have species-specific patterns in host

  19. Salicylic Acid Is Involved in the Basal Resistance of Tomato Plants to Citrus Exocortis Viroid and Tomato Spotted Wilt Virus.

    Science.gov (United States)

    López-Gresa, M Pilar; Lisón, Purificación; Yenush, Lynne; Conejero, Vicente; Rodrigo, Ismael; Bellés, José María

    2016-01-01

    Tomato plants expressing the NahG transgene, which prevents accumulation of endogenous salicylic acid (SA), were used to study the importance of the SA signalling pathway in basal defence against Citrus Exocortis Viroid (CEVd) or Tomato Spotted Wilt Virus (TSWV). The lack of SA accumulation in the CEVd- or TSWV-infected NahG tomato plants led to an early and dramatic disease phenotype, as compared to that observed in the corresponding parental Money Maker. Addition of acibenzolar-S-methyl, a benzothiadiazole (BTH), which activates the systemic acquired resistance pathway downstream of SA signalling, improves resistance of NahG tomato plants to CEVd and TSWV. CEVd and TSWV inoculation induced the accumulation of the hydroxycinnamic amides p-coumaroyltyramine, feruloyltyramine, caffeoylputrescine, and feruloylputrescine, and the defence related proteins PR1 and P23 in NahG plants earlier and with more intensity than in Money Maker plants, indicating that SA is not essential for the induction of these plant defence metabolites and proteins. In addition, NahG plants produced very high levels of ethylene upon CEVd or TSWV infection when compared with infected Money Maker plants, indicating that the absence of SA produced additional effects on other metabolic pathways. This is the first report to show that SA is an important component of basal resistance of tomato plants to both CEVd and TSWV, indicating that SA-dependent defence mechanisms play a key role in limiting the severity of symptoms in CEVd- and TSWV-infected NahG tomato plants.

  20. Salicylic Acid Is Involved in the Basal Resistance of Tomato Plants to Citrus Exocortis Viroid and Tomato Spotted Wilt Virus.

    Directory of Open Access Journals (Sweden)

    M Pilar López-Gresa

    Full Text Available Tomato plants expressing the NahG transgene, which prevents accumulation of endogenous salicylic acid (SA, were used to study the importance of the SA signalling pathway in basal defence against Citrus Exocortis Viroid (CEVd or Tomato Spotted Wilt Virus (TSWV. The lack of SA accumulation in the CEVd- or TSWV-infected NahG tomato plants led to an early and dramatic disease phenotype, as compared to that observed in the corresponding parental Money Maker. Addition of acibenzolar-S-methyl, a benzothiadiazole (BTH, which activates the systemic acquired resistance pathway downstream of SA signalling, improves resistance of NahG tomato plants to CEVd and TSWV. CEVd and TSWV inoculation induced the accumulation of the hydroxycinnamic amides p-coumaroyltyramine, feruloyltyramine, caffeoylputrescine, and feruloylputrescine, and the defence related proteins PR1 and P23 in NahG plants earlier and with more intensity than in Money Maker plants, indicating that SA is not essential for the induction of these plant defence metabolites and proteins. In addition, NahG plants produced very high levels of ethylene upon CEVd or TSWV infection when compared with infected Money Maker plants, indicating that the absence of SA produced additional effects on other metabolic pathways. This is the first report to show that SA is an important component of basal resistance of tomato plants to both CEVd and TSWV, indicating that SA-dependent defence mechanisms play a key role in limiting the severity of symptoms in CEVd- and TSWV-infected NahG tomato plants.

  1. Manuka oil and phoebe oil are attractive baits for xyleborus glabratus (coleoptera: scolytinae), the vector of Laurel Wilt

    Science.gov (United States)

    James L. Hanula; Brian Sullivan

    2008-01-01

    Redbay ambrosia beetle, Xyleborus glabratus Eichhoff, is a native of Southeast Asia recently established in coastal forests of Georgia, SC and Florida It vectors a wilt fungus, Raffaeka sp., lethal to redbay trees, Persea borbonia L. Spreng, and certain other Lauraceae. No practical monitoring system exists for this beetle so we...

  2. Pedotransfer functions to estimate soil water content at field capacity and permanent wilting point in hot arid western India

    NARCIS (Netherlands)

    Santra, P.; Kumar, M.; Kumawat, R.N.; Painuli, D.K.; Hati, K.M.; Heuvelink, G.B.M.; Batjes, N.H.

    2018-01-01

    Characterization of soil water retention, e.g., water content at field capacity (FC) and permanent wilting point (PWP) over a landscape plays a key role in efficient utilization of available scarce water resources in dry land agriculture; however, direct measurement thereof for multiple locations in

  3. Assessment of oak wilt threat to habitat of the golden-cheeked warbler, an endangered species, in central Texas

    Science.gov (United States)

    David N. Appel; Kim S. Camilli

    2010-01-01

    A major epidemic of oak wilt, caused by Ceratocystis fagacearum (Bretz) Hunt, has been killing trees in Central Texas for at least 40 years. This has created large and expanding canopy gaps in the vast, homogenous live oak woodlands (Quercus fusiformis Small) in the Edwards Plateau region of Texas. The changes in stand...

  4. BRS FC402: high-yielding common bean cultivar with carioca grain, resistance to anthracnose and fusarium wilt

    Directory of Open Access Journals (Sweden)

    Leonardo Cunha Melo

    2016-12-01

    Full Text Available BRS FC402 is a common bean cultivar of the carioca-grain group with commercial grain quality, suitable for cultivation in 21 Brazilian states. Cultivar has a normal cycle (85-94 days, high yield potential (4479 kg ha-1, 10.1% higher mean yield than the controls (2462 kg ha-1 and resistance to fusarium wilt and anthracnose.

  5. Isolations from the redbay ambrosia beetle, Xyleborus glabratus, confirm that the laurel wilt pathogen, Raffaelea lauricola, originated in Asia

    Science.gov (United States)

    Thomas C. Harrington; Hye Young Yun; Sheng-Shan Lu; Hideaki Goto; Dilzara N. Aghayeva; Stephen W. Fraedrich

    2011-01-01

    The laurel wilt pathogen Raffaelea lauricola was hypothesized to have been introduced to the southeastern USA in the mycangium of the redbay ambrosia beetle, Xyleborus glabratus, which is native to Asia. To test this hypothesis adult X. glabratus were trapped in Taiwan and on Kyushu Island, Japan, in 2009, and dead beetles were sent to USA for isolation of fungal...

  6. The role of weeds in the spread of Tomato spotted wilt virus by thrips tabaci (Thysanoptera: Thripidae) in tobacco crops

    NARCIS (Netherlands)

    Chatzivassiliou, E.K.; Peters, D.; Katis, N.I.

    2007-01-01

    Oviposition of Thrips tabaci, larval development and their potential to acquire Tomato spotted wilt virus (TSWV) from infected Amaranthus retroflexus, Datura stramonium, Lactuca serriola, Solanum nigrum and Sonchus oleraceus plants and the ability of the adults to transmit this virus to these weeds

  7. Tsw gene-based resistance is triggered by a functional RNA silencing suppressor protein of the Tomato spotted wilt virus

    NARCIS (Netherlands)

    Ronde, de D.; Butterbach, P.B.E.; Lohuis, H.; Hedil, M.; Lent, van J.W.M.; Kormelink, R.J.M.

    2013-01-01

    As a result of contradictory reports, the avirulence (Avr) determinant that triggers Tsw gene-based resistance in Capsicum annuum against the Tomato spotted wilt virus (TSWV) is still unresolved. Here, the N and NSs genes of resistance-inducing (RI) and resistance-breaking (RB) isolates were cloned

  8. Vertical Distribution and Daily Flight Periodicity of Ambrosia Beetles (Coleoptera: Curculionidae) in Florida Avocado Orchards Affected by Laurel Wilt

    Science.gov (United States)

    Ambrosia beetles have emerged as significant pests of avocado (Persea americana Miller) due to their association with pathogenic fungal symbionts, most notably Raffaelea lauricola, the causal agent of laurel wilt. We evaluated the interaction of ambrosia beetles with host avocado trees by documentin...

  9. Responses of nitrogen metabolism and seed nutrition to drought stress in soybean genotypes differing in slow-wilting phenotype

    Directory of Open Access Journals (Sweden)

    Nacer eBellaloui

    2013-12-01

    Full Text Available Recent advances in soybean breeding have resulted in genotypes that express the slow-wilting phenotype (trait under drought stress conditions. The physiological mechanisms of this trait remain unknown due to the complexity of trait × environment interactions. The objective of this research was to investigate nitrogen metabolism and leaf and seed nutrients composition of the slow-wilting soybean genotypes under drought stress conditions. A repeated greenhouse experiment was conducted using check genotypes: NC-Roy (fast wilting, Boggs (intermediate in wilting; and NTCPR94-5157 and N04-9646 (slow-wilting, SLW genotypes. Plants were either well-watered or drought stressed. Results showed that under well-watered conditions, nitrogen fixation (NF, nitrogen assimilation (NA, and leaf and seed composition differed between genotypes. Under drought stress, NF and NA were higher in NTCPR94-5157 and N04-9646 than in NC-Roy and Boggs. Under severe water stress, however, NA was low in all genotypes. Leaf water potential was significantly lower in checks (-2.00 MPa than in the SLW genotypes (-1.68 MPa. Leaf and seed concentrations of K, P, Ca, Cu, Na, B were higher in SLW genotypes than in the checks under drought stress conditions. Seed protein, oleic acid, and sugars were higher in SLW genotypes, and oil, linoleic and linolenic acids were lower in SLW genotypes. This research demonstrated that K, P, Ca, Cu, Na, and B may be involved in SLW trait by maintaining homeostasis and osmotic regulation. Maintaining higher leaf water potential in NTCPR94-5157 and N04-9646 under drought stress could be a possible water conservation mechanism to maintain leaf turgor pressure. The increase in osmoregulators such as minerals, raffinose and stachyose, and oleic acid could be beneficial for soybean breeders in selecting for drought stress tolerance.

  10. Specific PCR detection of Fusarium oxysporum f. sp. raphani: a causal agent of Fusarium wilt on radish plants.

    Science.gov (United States)

    Kim, H; Hwang, S-M; Lee, J H; Oh, M; Han, J W; Choi, G J

    2017-08-01

    Fusarium oxysporum, a causal agent of Fusarium wilt, is one of the most important fungal pathogens worldwide, and detection of F. oxysporum DNA at the forma specialis level is crucial for disease diagnosis and control. In this study, two novel F. oxysporum f. sp. raphani (For)-specific primer sets were designed, FOR1-F/FOR1-R and FOR2-F/FOR2-R, to target FOQG_17868 and FOQG_17869 ORFs, respectively, which were selected based on the genome comparison of other formae speciales of F. oxysporum including conglutinans, cubense, lycopersici, melonis, and pisi. The primer sets FOR1-F/FOR1-R and FOR2-F/FOR2-R that amplified a 610- and 425-bp DNA fragment, respectively, were specific to For isolates which was confirmed using a total of 40 F. oxysporum isolates. From infected plants, the FOR2-F/FOR2-R primer set directly detected the DNA fragment of For isolates even when the radish plants were collected in their early stage of disease development. Although the loci targeted by the For-specific primer sets were not likely involved in the pathogenesis, the primer set FOR2-F/FOR2-R is available for the determination of pathogenicity of radish-infecting F. oxysporum isolates. This study is the first report providing novel primer sets to detect F. oxysporum f. sp. raphani. Because plant pathogenic Fusarium oxysporum has been classified into special forms based on its host specificity, identification of F. oxysporum usually requires a pathogenicity assay as well as knowledge of the morphological characteristics. For rapid and reliable diagnosis, this study provides PCR primer sets that specifically detect Fusarium oxysporum f. sp. raphani (For) which is a devastating pathogen of radish plants. Because one of the primer sets directly detected the DNA fragment of For isolates from infected plants, the specific PCR method demonstrated in this study will provide a foundation for integrated disease management practices in commodity crops. © 2017 The Society for Applied Microbiology.

  11. Detection of Verticillium wilt of olive trees and downy mildew of opium poppy using hyperspectral and thermal UAV imagery

    Science.gov (United States)

    Calderón Madrid, Rocío; Navas Cortés, Juan Antonio; Montes Borrego, Miguel; Landa del Castillo, Blanca Beatriz; Lucena León, Carlos; Jesús Zarco Tejada, Pablo

    2014-05-01

    The present study explored the use of high-resolution thermal, multispectral and hyperspectral imagery as indicators of the infections caused by Verticillium wilt (VW) in olive trees and downy mildew (DM) in opium poppy fields. VW, caused by the soil-borne fungus Verticillium dahliae, and DM, caused by the biotrophic obligate oomycete Peronospora arborescens, are the most economically limiting diseases of olive trees and opium poppy, respectively, worldwide. V. dahliae infects the plant by the roots and colonizes its vascular system, blocking water flow and eventually inducing water stress. P. arborescens colonizes the mesophyll, appearing the first symptoms as small chlorotic leaf lesions, which can evolve to curled and thickened tissues and systemic infections that become deformed and necrotic as the disease develops. The work conducted to detect VW and DM infection consisted on the acquisition of time series of airborne thermal, multispectral and hyperspectral imagery using 2-m and 5-m wingspan electric Unmanned Aerial Vehicles (UAVs) in spring and summer of three consecutive years (2009 to 2011) for VW detection and on three dates in spring of 2009 for DM detection. Two 7-ha commercial olive orchards naturally infected with V. dahliae and two opium poppy field plots artificially infected by P. arborescens were flown. Concurrently to the airborne campaigns, olive orchards and opium poppy fields were assessed "in situ" to assess actual VW severity and DM incidence. Furthermore, field measurements were conducted at leaf and crown level. The field results related to VW detection showed a significant increase in crown temperature (Tc) minus air temperature (Ta) and a decrease in leaf stomatal conductance (G) as VW severity increased. This reduction in G was associated with a significant increase in the Photochemical Reflectance Index (PRI570) and a decrease in chlorophyll fluorescence. DM asymptomatic leaves showed significantly higher NDVI and lower green/red index

  12. RNA silencing is required for Arabidopsis defence against Verticillium wilt disease

    NARCIS (Netherlands)

    Ellendorff, U.; Fradin, E.F.; Jonge, de R.; Thomma, B.P.H.J.

    2009-01-01

    RNA silencing is a conserved mechanism in eukaryotes that plays an important role in various biological processes including regulation of gene expression. RNA silencing also plays a role in genome stability and protects plants against invading nucleic acids such as transgenes and viruses. Recently,

  13. Linking land management, the soil microbiome and suppression of Fusarium wilt disease

    NARCIS (Netherlands)

    Xiong, Wu

    2018-01-01

    Plant pathogens cause great loss of food production across the world. This problem is even more important given the need to produce more food for a growing human population. Given the negative effects of current pesticide-based management strategies, there is an urgent need to develop more

  14. Operational disease screening program for resistance to wilt in Acacia koa in Hawaii

    Science.gov (United States)

    Nick Dudley; Robert James; Richard Sniezko; Phil Cannon; Aileen Yeh; Tyler Jones; Michael Kaufmann

    2012-01-01

    In Hawaii, koa (Acacia koa A. Gray) is a valuable tree species economically, ecologically, and culturally. With significant land use change and declines in sugarcane, pineapple, and cattle production, there is an opportunity and keen interest in utilizing native koa in reforestation and restoration efforts. However, moderate to high mortality rates...

  15. Antiviral RNA silencing suppression activity of Tomato spotted wilt virus NSs protein.

    Science.gov (United States)

    Ocampo Ocampo, T; Gabriel Peralta, S M; Bacheller, N; Uiterwaal, S; Knapp, A; Hennen, A; Ochoa-Martinez, D L; Garcia-Ruiz, H

    2016-06-17

    In addition to regulating gene expression, RNA silencing is an essential antiviral defense system in plants. Triggered by double-stranded RNA, silencing results in degradation or translational repression of target transcripts. Viruses are inducers and targets of RNA silencing. To condition susceptibility, most plant viruses encode silencing suppressors that interfere with this process, such as the Tomato spotted wilt virus (TSWV) NSs protein. The mechanism by which NSs suppresses RNA silencing and its role in viral infection and movement remain to be determined. We cloned NSs from the Hawaii isolate of TSWV and using two independent assays show for the first time that this protein restored pathogenicity and supported the formation of local infection foci by suppressor-deficient Turnip mosaic virus and Turnip crinkle virus. Demonstrating the suppression of RNA silencing directed against heterologous viruses establishes the foundation to determine the means used by NSs to block this antiviral process.

  16. Genetic relatedness of Trichoderma isolates antagonistic against Fusarium oxysporum f.sp. dianthi inflicting carnation wilt.

    Science.gov (United States)

    Shanmugam, V; Sharma, Vivek; Ananthapadmanaban

    2008-01-01

    Twenty-eight isolates of Trichoderma belonging to four different species were screened in vitro for their antagonistic ability against Fusarium oxysporum f.sp. dianthi causing carnation wilt. Three different levels of antagonism observed in dual plate assay were further confirmed by cell-free culture filtrate experiments. Isolates showing class I level of antagonism produced maximum lytic enzymes, chitinases and beta-1,3-glucanases. Genetic variability of 25 selected isolates was assessed by random amplified polymorphic DNA technique and the amplified products were correlated for their level of antagonism. Unweighed pair-group method with arithmetical averages cluster analysis revealed prominent inter-and intraspecific genetic variation among the isolates. Based on their genetic relationship, the isolates were mainly distributed into 3 major groups representing T. atroviride, T. pseudokoningii and T. harzianum, with 20-35% interspecific dissimilarity. However, the polymorphism shown by the isolates did not correlate to their level of antagonism.

  17. Development of DArT markers and assessment of diversity in Fusarium oxysporum f. sp. ciceris, wilt pathogen of chickpea (Cicer arietinum L.).

    Science.gov (United States)

    Sharma, Mamta; Nagavardhini, Avuthu; Thudi, Mahendar; Ghosh, Raju; Pande, Suresh; Varshney, Rajeev K

    2014-06-10

    Fusarium oxysporum f. sp. ciceris (Foc), the causal agent of Fusarium wilt of chickpea is highly variable and frequent recurrence of virulent forms have affected chickpea production and exhausted valuable genetic resources. The severity and yield losses of Fusarium wilt differ from place to place owing to existence of physiological races among isolates. Diversity study of fungal population associated with a disease plays a major role in understanding and devising better disease control strategies. The advantages of using molecular markers to understand the distribution of genetic diversity in Foc populations is well understood. The recent development of Diversity Arrays Technology (DArT) offers new possibilities to study the diversity in pathogen population. In this study, we developed DArT markers for Foc population, analysed the genetic diversity existing within and among Foc isolates, compared the genotypic and phenotypic diversity and infer the race scenario of Foc in India. We report the successful development of DArT markers for Foc and their utility in genotyping of Foc collections representing five chickpea growing agro-ecological zones of India. The DArT arrays revealed a total 1,813 polymorphic markers with an average genotyping call rate of 91.16% and a scoring reproducibility of 100%. Cluster analysis, principal coordinate analysis and population structure indicated that the different isolates of Foc were partially classified based on geographical source. Diversity in Foc population was compared with the phenotypic variability and it was found that DArT markers were able to group the isolates consistent with its virulence group. A number of race-specific unique and rare alleles were also detected. The present study generated significant information in terms of pathogenic and genetic diversity of Foc which could be used further for development and deployment of region-specific resistant cultivars of chickpea. The DArT markers were proved to be a powerful

  18. Screening strawberry plants for anthracnose disease resistance using traditional and molecular techniques

    Science.gov (United States)

    Anthracnose is one of the most destructive diseases of strawberry which may cause fruit rot, leaf and petiole lesions, crown rot, wilt, and death. Crop loss due to anthracnose diseases can reach into the millions of dollars. Three species of Colletotrichum are considered causative agents of anthr...

  19. Do mites phoretic on elm bark beetles contribute to the transmission of Dutch elm disease?

    Science.gov (United States)

    John Moser; Heino Konrad; Stacy Blomquist; Thomas Kirisits

    2010-01-01

    Dutch elm disease (DED) is a destructive vascular wilt disease of elm (Ulmus) trees caused by the introduced Ascomycete fungus Ophiostoma novo-ulmi. In Europe, this DED pathogen is transmitted by elm bark beetles in the genus Scolytus. These insects carry phoretic mites to new, suitable habitats. The aim of this...

  20. Mapping global potential risk of mango sudden decline disease caused by fungus Ceratocystis fimbriata

    Science.gov (United States)

    Mango Sudden Decline (MSD), sometimes referred to as mango wilt, is an important disease of mango caused by one of the most significant fungal species causing disease in woody plants, Ceratocystis fimbriata. This species is mainly disseminated by the mango bark beetle, Hypocryphalus mangiferae (Steb...

  1. Dutch elm disease pathogen transmission by the banded elm bark beetle Scolytus schevyrewi

    Science.gov (United States)

    W. R. Jacobi; R. D. Koski; J. F. Negron

    2013-01-01

    Dutch Elm Disease (DED) is a vascular wilt disease of Ulmus species (elms) incited in North America primarily by the exotic fungus Ophiostoma novo-ulmi. The pathogen is transmitted via root grafts and elm bark beetle vectors, including the native North American elm bark beetle, Hylurgopinus rufipes and the exotic smaller European elm bark beetle, Scolytus multistriatus...

  2. Genome-wide analysis of autophagy-related genes in banana highlights MaATG8s in cell death and autophagy in immune response to Fusarium wilt.

    Science.gov (United States)

    Wei, Yunxie; Liu, Wen; Hu, Wei; Liu, Guoyin; Wu, Chunjie; Liu, Wei; Zeng, Hongqiu; He, Chaozu; Shi, Haitao

    2017-08-01

    MaATG8s play important roles in hypersensitive-like cell death and immune response, and autophagy is essential for disease resistance against Foc in banana. Autophagy is responsible for the degradation of damaged cytoplasmic constituents in the lysosomes or vacuoles. Although the effects of autophagy have been extensively revealed in model plants, the possible roles of autophagy-related gene in banana remain unknown. In this study, 32 MaATGs were identified in the draft genome, and the profiles of several MaATGs in response to fungal pathogen Fusarium oxysporum f. sp. cubense (Foc) were also revealled. We found that seven MaATG8s were commonly regulated by Foc. Through transient expression in Nicotiana benthamiana leaves, we highlight the novel roles of MaATG8s in conferring hypersensitive-like cell death, and MaATG8s-mediated hypersensitive response-like cell death is dependent on autophagy. Notablly, autophagy inhibitor 3-methyladenine (3-MA) treatment resulted in decreased disease resistance in response to Foc4, and the effect of 3-MA treatment could be rescued by exogenous salicylic acid, jasmonic acid and ethylene, indicating the involvement of autophagy-mediated plant hormones in banana resistance to Fusarium wilt. Taken together, this study may extend our understanding the putative role of MaATG8s in hypersensitive-like cell death and the essential role of autophagy in immune response against Foc in banana.

  3. Inoculation of tomato seedlings with Trichoderma Harzianum and Arbuscular Mycorrhizal Fungi and their effect on growth and control of wilt in tomato seedlings

    Directory of Open Access Journals (Sweden)

    Margaret W. Mwangi

    2011-06-01

    Full Text Available A green house study was conducted to investigate the ability of an isolate of Trichoderma harzianum (P52 and arbuscular mycorrhizal fungi (AMF in enhancing growth and control of a wilt pathogen caused by Fusarium oxysporum f. sp. lycopersici in tomato seedlings. The plants were grown in plastic pots filled with sterilized soils. There were four treatments applied as follows; P52, AMF, AMF + P52 and a control. A completely randomized design was used and growth measurements and disease assessment taken after 3, 6 and 9 weeks. Treatments that significantly (P < 0.05 enhanced heights and root dry weights were P52, AMF and a treatment with a combination of both P52 and AMF when compared the control. The treatment with both P52 and AMF significantly (P < 0.05 enhanced all growth parameters (heights; shoot and root dry weight investigated compared to the control. Disease severity was generally lower in tomato plants grown with isolate P52 and AMF fungi either individually or when combined together, though the effect was not statistically significant (P0.05. A treatment combination of P52 + AMF had less trend of severity as compared to each individual fungus. T. harzianum and AMF can be used to enhance growth in tomato seedlings.

  4. Evidence for an Opportunistic and Endophytic Lifestyle of the Bursaphelenchus xylophilus-Associated Bacteria Serratia marcescens PWN146 Isolated from Wilting Pinus pinaster.

    Science.gov (United States)

    Vicente, Cláudia S L; Nascimento, Francisco X; Barbosa, Pedro; Ke, Huei-Mien; Tsai, Isheng J; Hirao, Tomonori; Cock, Peter J A; Kikuchi, Taisei; Hasegawa, Koichi; Mota, Manuel

    2016-10-01

    Pine wilt disease (PWD) results from the interaction of three elements: the pathogenic nematode, Bursaphelenchus xylophilus; the insect-vector, Monochamus sp.; and the host tree, mostly Pinus species. Bacteria isolated from B. xylophilus may be a fourth element in this complex disease. However, the precise role of bacteria in this interaction is unclear as both plant-beneficial and as plant-pathogenic bacteria may be associated with PWD. Using whole genome sequencing and phenotypic characterization, we were able to investigate in more detail the genetic repertoire of Serratia marcescens PWN146, a bacterium associated with B. xylophilus. We show clear evidence that S. marcescens PWN146 is able to withstand and colonize the plant environment, without having any deleterious effects towards a susceptible host (Pinus thunbergii), B. xylophilus nor to the nematode model C. elegans. This bacterium is able to tolerate growth in presence of xenobiotic/organic compounds, and use phenylacetic acid as carbon source. Furthermore, we present a detailed list of S. marcescens PWN146 potentials to interfere with plant metabolism via hormonal pathways and/or nutritional acquisition, and to be competitive against other bacteria and/or fungi in terms of resource acquisition or production of antimicrobial compounds. Further investigation is required to understand the role of bacteria in PWD. We have now reinforced the theory that B. xylophilus-associated bacteria may have a plant origin.

  5. Fontes de resistência à murcha bacteriana em germoplasma de Capsicum spp. do estado do Amazonas Sources of resistance against bacterial wilt in Capsicum spp. germoplasm of the Amazonas state

    Directory of Open Access Journals (Sweden)

    Liane Cristine Rebouças Demosthenes

    2011-01-01

    Full Text Available A murcha bacteriana, causada por Ralstonia solanacearum, é uma das doenças mais importantes do gênero Capsicum no Brasil. No Amazonas, as condições de elevada temperatura e umidade favorecem o desenvolvimento da doença. O objetivo deste trabalho foi avaliar a resistência à murcha bacteriana de germoplasma, selvagem e comercial, de Capsicum spp. Foram avaliados 22 acessos de Capsicum em casa de vegetação. A inoculação foi feita mediante ferimento das raízes, seguido de adição no solo, ao redor das plantas, de suspensão bacteriana na concentração de 10(8 ufc mL-1. A avaliação foi feita diariamente a partir do quarto dia após a inoculação, em função desenvolvimento dos sintomas. A partir das médias de progresso dos sintomas foi construída a área abaixo da curva de progresso da doença (AACPD, e os dados submetidos ao teste de Scott-Knott ao nível de 5% de probabilidade, utilizando o programa estatístico SAEG 9.1. Foram selecionados os acessos 30, 20 e 17, da espécie C. chinense, como resistentes à murcha bacteriana para ensaios futuros em programas de melhoramento genético.The bacterial wilt caused by Ralstonia solanacearum is one of the most important in the genus Capsicum in Brazil. In the state of Amazonas, high temperatures and humidity favor the development of the disease. The objective of this work was to evaluate resistance in germoplasm of wild and commercial Capsicum spp. to bacterial wilt. Twenty two accesses of Capsicum spp. were evaluated in greenhouse conditions. The inoculation was made by means of wounds in the roots, followed by addition of bacterial suspension in the concentration of 10(8 ufc ml-1 in the soil, around the plants. Plant evaluation was made daily after the fourth day of the inoculation (DAI considering the symptoms progress. From the average progress of symptoms was constructed the area under the disease progress curve (AUDPC, and the data submitted to the Scott-Knott test at 5% of

  6. Effects of stage of maturity at harvest, wilting and LAB inoculant on aerobic stability of wheat silages

    DEFF Research Database (Denmark)

    Weinberg, Z.G.; Khanal, Prabhat; Chen, Y.

    2010-01-01

    of maturity were ensiled in mini-silos, either directly after cutting (DC) or after wilting (W). After 2-7 months of storage, silages were subjected to a 7-day aerobic stability test during which changes in chemical composition, dry matter (DM) and neutral detergent fiber (aNDF) digestibility, and temperature......, as well as DM losses and CO production, were measured. Silages from wheat cultivar BH were relatively dry (DM between 287 and 430 g/kg) and were mostly stable upon aerobic exposure. The flowering wheat of cultivar Galil was moister (DM of 199 g/kg), and the DC silages were stable upon aerobic exposure...... spoilage indicators. The inoculant enhanced CO production in the silages prepared from the DC wheat of the flowering and milk stages, as compared with the respective non-inoculated control silages which contained high concentrations of VFA. However, in the wilted silages which contained less VFA, both...

  7. Rhizosphere Microbiome Recruited from a Suppressive Compost Improves Plant Fitness and Increases Protection against Vascular Wilt Pathogens of Tomato

    Science.gov (United States)

    Antoniou, Anastasis; Tsolakidou, Maria-Dimitra; Stringlis, Ioannis A.; Pantelides, Iakovos S.

    2017-01-01

    Suppressive composts represent a sustainable approach to combat soilborne plant pathogens and an alternative to the ineffective chemical fungicides used against those. Nevertheless, suppressiveness to plant pathogens and reliability of composts are often inconsistent with unpredictable effects. While suppressiveness is usually attributed to the compost’s microorganisms, the mechanisms governing microbial recruitment by the roots and the composition of selected microbial communities are not fully elucidated. Herein, the purpose of the study was to evaluate the impact of a compost on tomato plant growth and its suppressiveness against Fusarium oxysporum f. sp. lycopersici (Foxl) and Verticillium dahliae (Vd). First, growth parameters of tomato plants grown in sterile peat-based substrates including 20 and 30% sterile compost (80P/20C-ST and 70P/30C-ST) or non-sterile compost (80P/20C and 70P/30C) were evaluated in a growth room experiment. Plant height, total leaf surface, and fresh and dry weight of plants grown in the non-sterile compost mixes were increased compared to the plants grown in the sterile compost substrates, indicating the plant growth promoting activity of the compost’s microorganisms. Subsequently, compost’s suppressiveness against Foxl and Vd was evaluated with pathogenicity experiments on tomato plants grown in 70P/30C-ST and 70P/30C substrates. Disease intensity was significantly less in plants grown in the non-sterile compost than in those grown in the sterile compost substrate; AUDPC was 2.3- and 1.4-fold less for Foxl and Vd, respectively. Moreover, fungal quantification in planta demonstrated reduced colonization in plants grown in the non-sterile mixture. To further investigate these findings, we characterized the culturable microbiome attracted by the roots compared to the unplanted compost. Bacteria and fungi isolated from unplanted compost and the rhizosphere of plants were sequence-identified. Community-level analysis revealed

  8. Combinatorial efficacy of Trichoderma spp. and Pseudomonas fluorescens to enhance suppression of cell wall degrading enzymes produced by Fusarium wilt of Arachis hypogaea.L

    Directory of Open Access Journals (Sweden)

    P Rajeswari

    2017-12-01

    Full Text Available Fusarium oxysporum, the soil borne pathogen causes vascular wilt, on majority of crop plants. It has been demonstrated that two different species of Trichoderma and Pseudomonas fluorescens suppress disease by different mechanisms. Therefore, application of a mixture of these biocontrol agents, and thus of several suppressive mechanisms, may represent a viable control strategy. A necessity for biocontrol by combinations of biocontrol agents can be the compatibility of the co-inoculated micro-organisms. Hence, compatibility between Trichoderma spp. and Pseudomonas fluorescens that have the ability to suppress Fusarium oxysporum in vitro on the activity of pectinolytic enzymes of Fusarium oxysporum. The activity of pectinolytic enzymes, i.e. pectin methyl esterase, endo and exo polymethylgalacturonases and exo and endo pectin trans eliminases produced by Fusarium oxysporum (Control was higher. Maximum inhibition of pectin methylesterase, exo and endo polymethylgalacturonase and exo and endopectin trans eliminase was shown by culture filtrate of Trichoderma viride + Pseudomonas fluorescens (Tv+Pf (1+2%, followed by Trichoderma harzianum + Pseudomonas fluorescens, (Th +Pf (1.5+2% and Trichoderma viride + Trichoderma harzianum (Tv+Th (1+1.5%. However, pathogenecity suppression of Fusarium oxysporum, a causative of Arachis hypogaea. L by the compatible combination of Trichodema viride + Pseudomonas fluorescens (1+2% was significantly better as compared to the single bio-agent. This indicates that specific interactions between biocontrol agents influence suppression of pathogenicity factors directly by combinations of these compatible bio-agents.

  9. CCR4-Not Complex Subunit Not2 Plays Critical Roles in Vegetative Growth, Conidiation and Virulence in Watermelon Fusarium Wilt Pathogen Fusarium oxysporum f. sp. niveum

    Science.gov (United States)

    Dai, Yi; Cao, Zhongye; Huang, Lihong; Liu, Shixia; Shen, Zhihui; Wang, Yuyan; Wang, Hui; Zhang, Huijuan; Li, Dayong; Song, Fengming

    2016-01-01

    CCR4-Not complex is a multifunctional regulator that plays important roles in multiple cellular processes in eukaryotes. In the present study, the biological function of FonNot2, a core subunit of the CCR4-Not complex, was explored in Fusarium oxysporum f. sp. niveum (Fon), the causal agent of watermelon wilt disease. FonNot2 was expressed at higher levels in conidia and germinating conidia and during infection in Fon-inoculated watermelon roots than in mycelia. Targeted disruption of FonNot2 resulted in retarded vegetative growth, reduced conidia production, abnormal conidial morphology, and reduced virulence on watermelon. Scanning electron microscopy observation of infection behaviors and qRT-PCR analysis of in planta fungal growth revealed that the ΔFonNot2 mutant was defective in the ability to penetrate watermelon roots and showed reduced fungal biomass in root and stem of the inoculated plants. Phenotypic and biochemical analyses indicated that the ΔFonNot2 mutant displayed hypersensitivity to cell wall perturbing agents (e.g., Congo Red and Calcofluor White) and oxidative stress (e.g., H2O2 and paraquat), decreased fusaric acid content, and reduced reactive oxygen species (ROS) production during spore germination. Our data demonstrate that FonNot2 plays critical roles in regulating vegetable growth, conidiogenesis and conidia morphology, and virulence on watermelon via modulating cell wall integrity, oxidative stress response, ROS production and FA biosynthesis through the regulation of transcription of genes involved in multiple pathways. PMID:27695445

  10. Improvement of Verticillium Wilt Resistance by Applying Arbuscular Mycorrhizal Fungi to a Cotton Variety with High Symbiotic Efficiency under Field Conditions

    Science.gov (United States)

    Zhang, Qiang; Gao, Xinpeng; Ren, Yanyun; Ding, Xinhua; Qiu, Jiajia; Li, Ning; Zeng, Fanchang

    2018-01-01

    Arbuscular mycorrhizal fungi (AMF) play an important role in nutrient cycling processes and plant stress resistance. To evaluate the effect of Rhizophagus irregularis CD1 on plant growth promotion (PGP) and Verticillium wilt disease, the symbiotic efficiency of AMF (SEA) was first investigated over a range of 3% to 94% in 17 cotton varieties. The high-SEA subgroup had significant PGP effects in a greenhouse. From these results, the highest-SEA variety of Lumian 1 was selected for a two-year field assay. Consistent with the performance from the greenhouse, the AMF-mediated PGP of Lumian 1 also produced significant results, including an increased plant height, stem diameter, number of petioles, and phosphorus content. Compared with the mock treatment, AMF colonization obviously inhibited the symptom development of Verticillium dahliae and more strongly elevated the expression of pathogenesis-related genes and lignin synthesis-related genes. These results suggest that AMF colonization could lead to the mycorrhiza-induced resistance (MIR) of Lumian 1 to V. dahliae. Interestingly, our results indicated that the AMF endosymbiont could directly inhibit the growth of phytopathogenic fungi including V. dahliae by releasing undefined volatiles. In summary, our results suggest that stronger effects of AMF application result from the high-SEA. PMID:29342876

  11. Improvement of Verticillium Wilt Resistance by Applying Arbuscular Mycorrhizal Fungi to a Cotton Variety with High Symbiotic Efficiency under Field Conditions

    Directory of Open Access Journals (Sweden)

    Qiang Zhang

    2018-01-01

    Full Text Available Arbuscular mycorrhizal fungi (AMF play an important role in nutrient cycling processes and plant stress resistance. To evaluate the effect of Rhizophagus irregularis CD1 on plant growth promotion (PGP and Verticillium wilt disease, the symbiotic efficiency of AMF (SEA was first investigated over a range of 3% to 94% in 17 cotton varieties. The high-SEA subgroup had significant PGP effects in a greenhouse. From these results, the highest-SEA variety of Lumian 1 was selected for a two-year field assay. Consistent with the performance from the greenhouse, the AMF-mediated PGP of Lumian 1 also produced significant results, including an increased plant height, stem diameter, number of petioles, and phosphorus content. Compared with the mock treatment, AMF colonization obviously inhibited the symptom development of Verticillium dahliae and more strongly elevated the expression of pathogenesis-related genes and lignin synthesis-related genes. These results suggest that AMF colonization could lead to the mycorrhiza-induced resistance (MIR of Lumian 1 to V. dahliae. Interestingly, our results indicated that the AMF endosymbiont could directly inhibit the growth of phytopathogenic fungi including V. dahliae by releasing undefined volatiles. In summary, our results suggest that stronger effects of AMF application result from the high-SEA.

  12. Isolation of a potential biocontrol agent Paenibacillus polymyxa NSY50 from vinegar waste compost and its induction of host defense responses against Fusarium wilt of cucumber.

    Science.gov (United States)

    Du, Nanshan; Shi, Lu; Yuan, Yinghui; Sun, Jin; Shu, Sheng; Guo, Shirong

    2017-09-01

    Fusarium wilt caused by Fusarium oxysporum f. sp. cucumerinum (FOC) is one of the major destructive soil-borne diseases infecting cucumber. In this study, we screened 60 target strains isolated from vinegar waste compost, from which 10 antagonistic strains were identified to have the disease suppression capacity of bio-control agents. The 16S rDNA gene demonstrated that the biocontrol agents were Paenibacillus polymyxa (P. polymyxa), Bacillus amyloliquefaciens (B. amyloliquefaciens) and Bacillus licheniformis (B. licheniformis). Based on the results of antagonistic activity experiments and pot experiment, an interesting strain of P. polymyxa (named NSY50) was selected for further research. Morphological, physiological and biochemical characteristics indicated that this strain was positive for protease and cellulase and produced indole acetic acid (22.21±1.27μg mL -1 ) and 1-aminocyclopropane-1-carboxylate deaminase (ACCD). NSY50 can significantly up-regulate the expression level of defense related genes PR1 and PR5 in cucumber roots at the early stages upon challenge with FOC. However, the gene expression levels of a set of defense-related genes, such as the plant nucleotide-binding site (NBS)-leucine-rich repeat (LRR) gene family (e.g., Csa001236, Csa09775, Csa018159), 26kDa phloem protein (Csa001568, Csa003306), glutathione-S-transferase (Csa017734) and phenylalanine ammonia-lyase (Csa002864) were suppressed by pretreatment with NSY50 compared with the single challenge with FOC after nine days of inoculation. Of particular interest was the reduced expression of these genes at disease progression stages, which may be required for F. oxysporum dependent necrotrophic disease development. Copyright © 2017 Elsevier GmbH. All rights reserved.

  13. Pattern of Flushing, Cherelle Wilt, and Accuracy of Yield Forecasting of Some Cocoa Clones

    Directory of Open Access Journals (Sweden)

    Adi Prawoto

    2014-08-01

    Full Text Available Monthly observation of cocoa flushing, number of cherelle wilt (CW, number of small, medium and large pods of 6 clones was conducted for two years to study its dynamics for one year. A study was conducted in Kaliwining Experimental Station, 45 m asl. and D rainfall type (according to Schmidt & Ferguson, using ICS 13, ICS 60, TSH 858, Sulawesi 1, Sulawesi 2 and KW 165 clones of 8 years old. Each clone was planted intermittently in separate rows, replicated 6 rows. Correlation and regression analysis were done between variables and with rainfall data. The parallel research was conducted in the similar station to assess the accuracy of production estimation method by identify percentage of small pods (length 1—10 cm, medium (11—15 cm and large pods (>15 cm to grow until harvested. The study used 15th years old trees of Sulawesi 1, Sulawesi 2, KW 165, KKM 22, ICS 13 and DR 2 clones. Each clones was replicated 5 times. The result showed that intensive flushing (>50% occured during January, March, September and November meanwhile no flushing during December and February. Correlation between rainfall and flushing was positive (r=0.27. Effect of clones on flushing frequency was similar but for flushing intensity was significant. KW 165 tended to be the lowest but TSH 858 tend to be the highest. CW occured for a year-round but the height level during May and June. Effect of clones was significant, KW 165 showed highest followed by Sulawesi 2. CW level showed positive correlation with number of medium (r=0.71 and big pods (r=0.55, except showed negative correlation with flushing intensity (r=-0.37 and rainfall (r=-0.51. High pod setting happened during May to November and low pod setting during December to March. In this aspect effect of clones were significant, the productive clones were Sulawesi 1, Sulawesi 2 and KW 165, but ICS 60 was the less. CW level during 1st semester was lower than at 2nd semester and clone effect was significant. The

  14. Expression analysis of fusarium wilt resistance gene in melon by real-time quantitative pcr

    International Nuclear Information System (INIS)

    Wang, X.; Xu, B.; Zhao, L.; Gao, P.; Luan, F.

    2014-01-01

    Melon Actin gene was used as a reference gene, to explore the gene expression profiles of the Fom-2 gene in roots, stems, and leaves of melon MR-1 under induction by Fusarium oxysporum f. sp. melonis. Monitoring using real-time quantitative PCR showed similar accumulation patterns of Fom-2 in roots, stems, and leaves over the observation period of 1 to 11 days; the expression level in stems was the highest. The expression of the Fom-2 gene was strengthened by the prolongation of induction time. In stems, the expression of Fom-2 was 5.737 times higher than in the control at three days; in roots, expression of Fom-2 was 5.617 times higher than in the control at five days. Similarly, the expression of Fom-2 in leaves obviously increased. It was 4.441 times higher than in the control at 5 days. The expression of Fom-2 was non-tissue specific, up-regulated under induction by Fusarium, and related to early resistance to Fusarium wilt. (author)

  15. Autoradiographic localization of the synthetic sites of tomato spoted wilt virus and potato virus Y

    International Nuclear Information System (INIS)

    Nogueira, N.L.; Silva, D.M.

    1982-01-01

    The biosynthesis sites were investigated of two morfologically different viruses - the Tomato Spotted Wilt Virus (TSWV-spherical particle) and the Potato Virus Y (PVY - long and flexuous particle) in order to discuss the hypothesis of De Zoeten and Schlegel about the relationship between virus morphology and the location of the viral biosynthesis. Samples from uninfected or infected leaves were immersed in distilled water or an aqueous solution and transfered to uridine tritiated solution. After washing in distilled water the samples were fixed, dehydrated and embedded in Epon 812 for electron microscopy conventional techniques. Ultrathin sections were covered with Ilford L-4 photographic emulsion and exposed for two months before photographic development, staining and examinated in the electron microscope. The number of silver grains per unit areas (grain density) in the electronphotomicrographs was used to compare the grains densities of some cells regions of tissues treated or not with AMD. The result indicated the endoplasmic reticulum as the most likely location of the TSWV-RNA replication. The same comparison made with tobacco cells infected with PVY showed that the cytoplasmic area is the most probable site of the PVY-RNA replication. The results obtained seem to show that the rule proposed by De Zoeten and Schlegel cannot be used for all plant viruses because the TSWV replicates in the cytoplasm of infected cell. These viruses seem to be exceptions to that rule. (Author) [pt

  16. Molecular characterization of a subtilase from the vascular wilt fungus Fusarium oxysporum.

    Science.gov (United States)

    Di Pietro, A; Huertas-González, M D; Gutierrez-Corona, J F; Martínez-Cadena, G; Méglecz, E; Roncero, M I

    2001-05-01

    The gene prt1 was isolated from the tomato vascular wilt fungus Fusarium oxysporum f. sp. lycopersici, whose predicted amino acid sequence shows significant homology with subtilisin-like fungal proteinases. Prt1 is a single-copy gene, and its structure is highly conserved among different formae speciales of F. oxysporum. Prt1 is expressed constitutively at low levels during growth on different carbon and nitrogen sources and strongly induced in medium containing collagen and glucose. As shown by reverse transcription-polymerase chain reaction and fluorescence microscopy of F. oxysporum strains carrying a prt1-promoter-green fluorescent protein fusion, prt1 is expressed at low levels during the entire cycle of infection on tomato plants. F. oxysporum strains transformed with an expression vector containing the prt1 coding region fused to the inducible endopolygalacturonase pg1 gene promoter and grown under promoter-inducing conditions secreted high levels of extracellular subtilase activity that resolved into a single peak of pI 4.0 upon isoelectric focusing. The active fraction produced two clearing bands of 29 and 32 kDa in sodium dodecyl sulfate gels containing gelatin. Targeted inactivation of prt1 in F. oxysporum f. sp. lycopersici had no detectable effect on mycelial growth, sporulation, and pathogenicity on tomato plants.

  17. Symptom and Resistance of Cultivated and Wild Capsicum Accessions to Tomato Spotted Wilt Virus

    Directory of Open Access Journals (Sweden)

    Jung-Heon Han

    2011-04-01

    Full Text Available One hundred Capsicum accessions were screened for symptomatic response and resistance to Tomato spotted wilt virus-pb1 (TSWV-pb1. Symptom and its severity rating were checked by visual observation at 9, 12, 14, and 45 days after inoculation, respectively. Enzyme-linked immune-sorbent assay was performed all tested individuals on non-inoculated upper leaves after the third rating to indentify viral infection. Leaf curling was predominant in almost susceptible individuals of each accession. Stem necrosis was most frequent in wild species while yellowing in commercial hybrids and Korean land race cultivars. Ring spot, a typical symptom of TSWV, was rarely detected in some of a few accessions. Different levels of resistance to TSWV-pb1 were observed among the tested accessions. High level of resistance was detected in 4 commercial cultivars of Kpc- 35, -36, -57, and -62, and 8 wild species of PBI-11, C00105, PBC076, PBC280, PBC426, PBC495, PBC537, and PI201238 through seedling test by mechanical inoculation.

  18. Serological and molecular characterization of Syrian Tomato spotted wilt virus isolates

    Directory of Open Access Journals (Sweden)

    Faiz ISMAEIL

    2015-04-01

    Full Text Available Thirty four Syrian isolates of Tomato spotted wilt virus (TSWV collected from tomato and pepper were tested against five specific monoclonal antibodies using TAS-ELISA. The isolates were in two serogroups. Fourteen tomato and sixteen pepper isolates were similar in their reaction with MAb-2, MAb-4, MAb-5 and MAb-6, but did not react with MAb-7 (Serogroup 1. Meanwhile, four isolates collected from pepper reacted with all the MAbs used (Serogroup 2. The expected 620 bp DNA fragment was obtained by RT-PCR from six samples using a specific primer pair designed to amplify the nucleocapsid protein (NP gene of TSWV. The PCR products were sequenced and a phylogenetic tree was constructed. Sequence analysis revealed that the Syrian TSWV isolates were very similar at the nucleotide (97.74 to 99.84% identity and amino acid (96.17 to 99.03% identity sequences levels. The phylogenetic tree showed high similarity of Syrian TSWV isolates with many other representative isolates from different countries.

  19. Tamanho do tubérculo-semente de batata não interfere na manifestação da murcha bacteriana Potato seed tuber size does not interfere with the incidence of potato bacterial wilt

    Directory of Open Access Journals (Sweden)

    Carlos A Lopes

    2011-06-01

    differ from each other and were more resistant than Agata and Bintje, which formed a statistically homogeneous pair. Differences on the seed tuber size and interactions between cultivars and tuber size were not significant. Therefore, the seed tuber size, within the limits covered in this paper, have no effect on disease incidence in field screening for potato resistance to the bacterial wilt.

  20. Transgenic approaches for development of disease resistance in banana

    International Nuclear Information System (INIS)

    Shekhawat, Upendra K.S.; Ghag, Siddhesh B.; Ganapathi, Thumballi R.

    2014-01-01

    Banana (Musa spp.) is an important food and cash crop worldwide. Diseases and pests pose the most serious constraint to banana cultivation. Among the diseases, Fusarium wilt and Banana Bunchy Top Virus (BBTV) are the most important economically. We have explored different transgenic approaches for development of efficient resistance in banana against these two diseases. For countering Fusarium wilt, we have over expressed Petunia floral defensins using a strong constitutive promoter in transgenic banana plants. We have also tested a host induced gene silencing strategy targeting two vital fungal genes to obtain Fusarium resistant banana plants. For development of BBTV resistant banana plants also, we have used a host-induced gene silencing approach utilizing the full and partial coding sequence of the viral replication initiation protein. Successful bioassays performed in controlled greenhouse conditions have shown the efficacy of using these strategies to develop disease resistant banana plants. (author)

  1. root rot disease of five fruit tree seedlings in the nursery

    African Journals Online (AJOL)

    KAMALDEEN

    on them. Our experience in the nursery in Port Harcourt had been that many tree species of the tropical region are susceptible to root rot diseases of fungal origin. The fungal invasion of the succulent root tissues causes the young tree seedlings to dieback; their leaves becomes discoloured, wilted and eventually dead.

  2. Use of nested PCR to detect Ceratocystis fagacearum in sapwood of diseased northern oak species

    Science.gov (United States)

    Early and accurate diagnosis of oak wilt, caused by Ceratocystis fagacearum (Cf), is important when disease control action is planned. When laboratory diagnosis is needed, standard isolation protocols that are used rely on high quality samples and require > 14 days for incubation. Use of a nested P...

  3. Comparative Agronomic Performance and Reaction to Fusarium wilt of Lens culinaris × L. orientalis and L. culinaris × L. ervoides derivatives

    Directory of Open Access Journals (Sweden)

    Mohar Singh

    2017-07-01

    Full Text Available The development of transgressive phenotype in the segregating populations has been speculated to contribute to niche divergence of hybrid lineages, which occurs most frequently at larger genetic distances. Wild Lens species are considered to be more resistant against major biotic and abiotic stresses than that of the cultivated species. In the present study, we assessed the comparative agronomic performance of lentil (Lens culinaris subsp. culinaris inter-sub-specific (L. culinaris subsp. orientalis and interspecific (L. ervoides derivatives, also discussed its probable basis of occurrence. The F3, F4, and F5 inter sub-specific and interspecific populations of ILL8006 × ILWL62 and ILL10829 × ILWL30, respectively revealed a substantial range of variation for majority of agro-morphological traits as reflected by the range, mean and coefficient of variation. A high level of fruitful heterosis was also observed in F3 and F4 progeny for important traits of interest. Phenotypic coefficient of variation (PCV was higher in magnitude than genotypic coefficient of variation (GCV in all generations for several quantitative characters. The results showed high heritability estimates for majority of traits in conjunction with low to high genetic advance in F3 and F4 generations. Further, F5 progeny of ILL10829 × ILWL30, manifested resistant disease reaction for fifteen recombinant inbred lines (RILs against (Fusarium oxysporum f. sp. lentis (Vasd. Srin. Gord.. The multilocation agronomic evaluation of both crosses showed better results for earliness, desirable seed yield and Fusarium wilt resistance under two agro-ecological regions of north-western India. These better performing recombinants of ILL8006 × ILWL62 and ILL10829 × ILWL30 can be advanced for further genetic improvement and developing high yielding disease resistant cultivars of lentil.

  4. Use of Nested and Real-Time PCR for the Detection of Ceratocystis fagacearum in the Sapwood of Diseased Oak Species in Minnesota

    Science.gov (United States)

    A. Yang; J. Juzwik

    2017-01-01

    Oak wilt caused by Ceratocystis fagacearum is a significant disease of Quercus spp. in the eastern United States. Early and accurate detection of the pathogen is particularly important when disease control is planned. Nested and real-time polymerase chain reaction (PCR) methods utilizing fungal DNA extracted from sapwood drill...

  5. Presence and Prevalence of Raffaelea lauricola, Cause of Laurel Wilt, in Different Species of Ambrosia Beetle in Florida, USA.

    Science.gov (United States)

    Ploetz, Randy C; Konkol, Joshua L; Narvaez, Teresa; Duncan, Rita E; Saucedo, Ramon J; Campbell, Alina; Mantilla, Julio; Carrillo, Daniel; Kendra, Paul E

    2017-04-01

    We summarize the information available on ambrosia beetle species that have been associated in Florida with Raffaelea lauricola T.C. Harr., Fraedrich & Aghayeva, the primary symbiont of Xyleborus glabratus Eichhoff and cause of laurel wilt. In total, 14 species in Ambrosiodmus, Euwallacea, Premnobius, Xyleborus, Xyleborinus, and Xylosandrus were either reared from laurel wilt-affected host trees or trapped in laurel wilt-affected stands of the same, and assayed for R. lauricola. In six collections from native species in the southeastern United States [Persea borbonia (L.), Persea palustris (Raf.) Sarg., and Persea humilis Nash] and four from avocado (Persea americana Mill.), extracted mycangia or heads (taxa with mandibular mycangia) or intact bodies (taxa with mycangia in other locations) were surface-disinfested before assays on a semi-selective medium for the isolation of Raffaelea (CSMA+). Raffaelea lauricola was identified based on its characteristic phenotype on CSMA+, and the identity of a random subset of isolates was confirmed with taxon-specific microsatellite markers. The pathogen was recovered from 34% (246 of 726) of the individuals that were associated with the native Persea spp., but only 6% (58 of 931) of those that were associated with avocado. Over all studies, R. lauricola was recovered from 10 of the ambrosia beetle species, but it was most prevalent in Xyleborus congeners. This is the first record of R. lauricola in Ambrosiodmus lecontei Hopkins, Xyleborinus andrewesi (Blandford), and Xyleborus bispinatus Eichhoff. The potential effects of R. lauricola's promiscuity are discussed. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  6. Induced resistant mutations in alfalfa and broad bean against rust, leaf spot and wilh diseases by Gamma rays and ethylmethanesulfonate

    International Nuclear Information System (INIS)

    1988-01-01

    In alfalfa after gamma irradiation with 50,100, and 150 krads, 38 rust resistant plants have been selected throughout a screening programme. During four months, cuttings were obtained from these plants individually. Results revealed that 20 plants were remar-kably surpassed the origin in the total fresh weight and in the average weight of each cutting. In broad bean, following gamma irradiation and EMS in two cuitivars for induction of wilt resistance. Seeds of these plants were sown in artificially infested soil . During the growing season, all susceptible plants were removed and at epidemic form of wilt disease

  7. Fusarium solani Infection Depressed Photosystem Performance by Inducing Foliage Wilting in Apple Seedlings

    Directory of Open Access Journals (Sweden)

    Kun Yan

    2018-05-01

    Full Text Available Fusarium fungi are soil-borne pathogens, and the pathological effects on plant photosystems remain unclear. This study aimed to deeply reveal pathological characterization in apple seedlings infected with Fusarium solani by investigating photosystems performance and interaction. Roots were immersed in conidial suspension for inoculation. Thereafter, prompt and delayed chlorophyll a fluorescence and modulated 820 nm reflection were simultaneously detected. After 30 days of infection, leaf relative water content and dry weight were remarkably decreased by 55.7 and 47.1%, suggesting that the infected seedlings were subjected to Fusarium-induced water deficit stress. PSI reaction center was more susceptible than PSII reaction center in infected seedlings due to greater decrease in the maximal photochemical efficiency of PSI than that of PSII, but PSI reaction center injury was aggravated slowly, as PSII injury could partly protect PSI by restricting electron donation. PSII donor and acceptor sides were also damaged after 20 days of infection, and the restricted electron donation induced PSII and PSI disconnection by blocking PSI re-reduction. In accordance with greater damage of PSI reaction center, PSI oxidation was also suppressed. Notably, significantly increased efficiency of electron transport from plastoquinone (PQ to PSI acceptors (REo/ETo after 20 days of infection suggested greater inhibition on PQ reduction than re-oxidation, and the protection for PSI acceptors might alleviate the reduction of electron transport efficiency beyond PQ upon damaged PSI reaction center. Lowered delayed fluorescence in microsecond domain verified PSII damage in infected seedlings, and elevated delayed fluorescence in sub-millisecond domain during PQ reduction process conformed to increased REo/ETo. In conclusion, F. solani infection depressed PSII and PSI performance and destroyed their coordination by inducing pathological wilting in apple seedlings. It may

  8. First report of the cucurbit yellow vine disease caused by Serratia marcescens in watermelon and yellow squash in Alabama

    Science.gov (United States)

    Symptoms typical of cucurbit yellow vine disease (CYVD) were first observed in a 2 ha watermelon field in Crawford, Russell County, Alabama on 8 June 2010. Watermelon plants, cv. 'Jubilee,' exhibited a yellow or chlorotic appearance and some plants were completely wilted. On 24 June plant samples ...

  9. Draft genome sequence of Serratia sp. strain M24T3, isolated from pinewood disease nematode Bursaphelenchus xylophilus.

    Science.gov (United States)

    Proença, Diogo Neves; Espírito Santo, Christophe; Grass, Gregor; Morais, Paula V

    2012-07-01

    Here we report the draft genome sequence of Serratia sp. strain M24T3, which is associated with pinewood nematode Bursaphelenchus xylophilus, the causative agent of pine wilt disease. Serratia sp. strain M24T3 has been identified as a bionematocide for B. xylophilus in vitro, and multiple genes potentially involved in virulence and nematotoxity were identified.

  10. Draft Genome Sequence of Serratia sp. Strain M24T3, Isolated from Pinewood Disease Nematode Bursaphelenchus xylophilus

    OpenAIRE

    Proença, Diogo Neves; Espírito Santo, Christophe; Grass, Gregor; Morais, Paula V.

    2012-01-01

    Here we report the draft genome sequence of Serratia sp. strain M24T3, which is associated with pinewood nematode Bursaphelenchus xylophilus, the causative agent of pine wilt disease. Serratia sp. strain M24T3 has been identified as a bionematocide for B. xylophilus in vitro, and multiple genes potentially involved in virulence and nematotoxity were identified.

  11. Quantification of propagules of the laurel wilt fungus and other mycangial fungi from the redbay ambrosia beetle, Xyleborus glabratus.

    Science.gov (United States)

    Harrington, T C; Fraedrich, S W

    2010-10-01

    The laurel wilt pathogen, Raffaelea lauricola, is a fungal symbiont of the redbay ambrosia beetle, Xyleborus glabratus, which is native to Asia and was believed to have brought R. lauricola with it to the southeastern United States. Individual X. glabratus beetles from six populations in South Carolina and Georgia were individually macerated in glass tissue grinders and serially diluted to quantify the CFU of fungal symbionts. Six species of Raffaelea were isolated, with up to four species from an individual adult beetle. The Raffaelea spp. were apparently within the protected, paired, mandibular mycangia because they were as numerous in heads as in whole beetles, and surface-sterilized heads or whole bodies yielded as many or more CFU as did nonsterilized heads or whole beetles. R. lauricola was isolated from 40 of the 41 beetles sampled, and it was isolated in the highest numbers, up to 30,000 CFU/beetle. Depending on the population sampled, R. subalba or R. ellipticospora was the next most frequently isolated species. R. arxii, R. fusca, and R. subfusca were only occasionally isolated. The laurel wilt pathogen apparently grows in a yeast phase within the mycangia in competition with other Raffaelea spp.

  12. Differential protein accumulations in isolates of the strawberry wilt pathogen Fusarium oxysporum f. sp. fragariae differing in virulence.

    Science.gov (United States)

    Fang, Xiangling; Barbetti, Martin J

    2014-08-28

    This study was conducted to define differences in Fusarium oxysporum f. sp. fragariae (Fof) isolates with different virulence efficiency to strawberry at the proteome level, in combination with their differences in mycelial growth, conidial production and germination. Comparative proteome analyses revealed substantial differences in mycelial proteomes between Fof isolates, where the 54 differentially accumulated protein spots were consistently over-accumulated or exclusively in the highly virulent isolate. These protein spots were identified through MALDI-TOF/TOF mass spectrometry analyses, and the identified proteins were mainly related to primary and protein metabolism, antioxidation, electron transport, cell cycle and transcription based on their putative functions. Proteins of great potential as Fof virulence factors were those involved in ubiquitin/proteasome-mediated protein degradation and reactive oxygen species detoxification; the hydrolysis-related protein haloacid dehalogenase superfamily hydrolase; 3,4-dihydroxy-2-butanone 4-phosphate synthase associated with riboflavin biosynthesis; and those exclusive to the highly virulent isolate. In addition, post-translational modifications may also make an important contribution to Fof virulence. F. oxysporum f. sp. fragariae (Fof), the causal agent of Fusarium wilt in strawberry, is a serious threat to commercial strawberry production worldwide. However, factors and mechanisms contributing to Fof virulence remained unknown. This study provides knowledge of the molecular basis for the differential expression of virulence in Fof, allowing new possibilities towards developing alternative and more effective strategies to manage Fusarium wilt. Copyright © 2014 Elsevier B.V. All rights reserved.

  13. Activation of salicylic acid metabolism and signal transduction can enhance resistance to Fusarium wilt in banana (Musa acuminata L. AAA group, cv. Cavendish).

    Science.gov (United States)

    Wang, Zhuo; Jia, Caihong; Li, Jingyang; Huang, Suzhen; Xu, Biyu; Jin, Zhiqiang

    2015-01-01

    Fusarium wilt caused by the fungus Fusarium oxysporum f. sp. cubens (Foc) is the most serious disease that attacks banana plants. Salicylic acid (SA) can play a key role in plant-microbe interactions. Our study is the first to examine the role of SA in conferring resistance to Foc TR4 in banana (Musa acuminata L. AAA group, cv. Cavendish), which is the greatest commercial importance cultivar in Musa. We used quantitative real-time reverse polymerase chain reaction (qRT-PCR) to analyze the expression profiles of 45 genes related to SA biosynthesis and downstream signaling pathways in a susceptible banana cultivar (cv. Cavendish) and a resistant banana cultivar (cv. Nongke No. 1) inoculated with Foc TR4. The expression of genes involved in SA biosynthesis and downstream signaling pathways was suppressed in a susceptible cultivar and activated in a resistant cultivar. The SA levels in each treatment arm were measured using high-performance liquid chromatography. SA levels were decreased in the susceptible cultivar and increased in the resistant cultivar. Finally, we examined the contribution of exogenous SA to Foc TR4 resistance in susceptible banana plants. The expression of genes involved in SA biosynthesis and signal transduction pathways as well as SA levels were significantly increased. The results suggest that one reason for banana susceptibility to Foc TR4 is that expression of genes involved in SA biosynthesis and SA levels are suppressed and that the induced resistance observed in banana against Foc TR4 might be a case of salicylic acid-dependent systemic acquired resistance.

  14. Identification of three new isolates of Tomato spotted wilt virus from different hosts in China: molecular diversity, phylogenetic and recombination analyses.

    Science.gov (United States)

    Zhang, Zhenjia; Wang, Deya; Yu, Chengming; Wang, Zenghui; Dong, Jiahong; Shi, Kerong; Yuan, Xuefeng

    2016-01-14

    Destructive diseases caused by Tomato spotted wilt virus (TSWV) have been reported associated with many important plants worldwide. Recently, TSWV was reported to infect different hosts in China. It is of value to clone TSWV isolates from different hosts and examine diversity and evolution among different TSWV isolates in China as well as worldwide. RT-PCR was used to clone the full-length genome (L, M and S segments) of three new isolates of TSWV that infected different hosts (tobacco, red pepper and green pepper) in China. Identity of nucleotide and amino acid sequences among TSWV isolates were analyzed by DNAMAN. MEGA 5.0 was used to construct phylogenetic trees. RDP4 was used to detect recombination events during evolution of these isolates. Whole-genome sequences of three new TSWV isolates in China were determined. Together with other available isolates, 29 RNA L, 62 RNA M and 66 RNA S of TSWV isolates were analyzed for molecular diversity, phylogenetic and recombination events. This analysis revealed that the entire TSWV genome, especially the M and S RNAs, had major variations in genomic size that mainly involve the A-U rich intergenic region (IGR). Phylogenetic analyses on TSWV isolates worldwide revealed evidence for frequent reassortments in the evolution of tripartite negative-sense RNA genome. Significant numbers of recombination events with apparent 5' regional preference were detected among TSWV isolates worldwide. Moreover, TSWV isolates with similar recombination events usually had closer relationships in phylogenetic trees. All five Chinese TSWV isolates including three TSWV isolates of this study and previously reported two isolates can be divided into two groups with different origins based on molecular diversity and phylogenetic analysis. During their evolution, both reassortment and recombination played roles. These results suggest that recombination could be an important mechanism in the evolution of multipartite RNA viruses, even negative

  15. Biological control of strawberry Fusarium wilt caused by Fusarium oxysporum f. sp. fragariae using Bacillus velezensis BS87 and RK1 formulation.

    Science.gov (United States)

    Nam, Myeong Hyeon; Park, Myung Soo; Kim, Hong Gi; Yoo, Sung Joon

    2009-05-01

    Two isolates, Bacillus sp. BS87 and RK1, selected from soil in strawberry fields in Korea, showed high levels of antagonism towards Fusarium oxysporum f. sp. fragariae in vitro. The isolates were identified as B. velezensis based on the homology of their gyrA sequences to reference strains. BS87 and RK1 were evaluated for control of Fusarium wilt in strawberries in pot trials and field trials conducted in Nonsan, Korea. In the pot trials, the optimum applied concentration of BS87 and RK1 for pre-plant root-dip application to control Fusarium wilt was 10(5) and 10(6) colony-forming units (CFU)/ml, respectively. Meanwhile, in the 2003 and 2005 field trials, the biological control efficacies of formulations of RK1 were similar to that of a conventional fungicide (copper hydroxide) when compared with a non-treated control. The RK1 formulation was also more effective than BS87 in suppressing Fusarium wilt under field conditions. Therefore, the results indicated that formulation of B.velezensis BS87 and RK1 may have potential to control Fusarium wilt in strawberries.

  16. Identification of pathogenicity-related genes in the vascular wilt fungus verticillium dahliae by agrobacterium tumefaciens-mediated t-DNA insertional mutagenesis.

    Science.gov (United States)

    Verticillium dahliae is the causal agent of vascular wilt in many economically important crops worldwide. Identification of genes that underpin pathogenicity or virulence may suggest targets for alternative control methods for this fungus. In this study, Agrobacterium tumefaciens-mediated transform...

  17. Alpha-tocopherol and β-carotene in legume-grass mixtures as influenced by wilting, ensiling and type of silage additive

    DEFF Research Database (Denmark)

    Lindqvist, H; Nadeau, E; Jensen, Søren Krogh

    2012-01-01

    Effects of wilting, ensiling and type of additive on α-tocopherol and β-carotene contents in legume–grass mixtures were examined. Swards of birdsfoot trefoil + timothy (Bft + Ti), red clover + timothy (Rc + Ti) and red clover + meadow fescue (Rc + Mf) were harvested as a first regrowth in August...

  18. Utility of essential oils for development of host-based lures for Xyleborus glabratus (Coleoptera: Curculionidae: Scolytinae), vector of laurel wilt

    Science.gov (United States)

    Redbay ambrosia beetle, Xyleborus glabratus, is native to Southeast Asia, but subsequent to introduction in Georgia in 2002, it has become a serious invasive pest in the USA, now established in nine southeastern states. Females vector Raffaelea lauricola, the fungus that causes laurel wilt, a letha...

  19. Selection for resistance to Verticillium wilt caused by race 2 isolates of Verticillium dahliae in accessions of lettuce (Lactuca sativa L.).

    Science.gov (United States)

    Verticillium wilt of lettuce caused by Verticillium dahliae can cause severe economic damage to lettuce producers. The pathogen exists as two races (races 1 and 2) in lettuce, and complete resistance to race 1 is known. Resistance to race 2 isolates has not been reported, and production of race 1 re...

  20. Comparative microbiome analysis of a Fusarium wilt suppressive soil and a Fusarium wilt conducive soil from the Châteaurenard region

    NARCIS (Netherlands)

    Siegel-Hertz, Katarzyna; Edel-Hermann, Véronique; Chapelle, E.; Terrat, Sébastien; Raaijmakers, Jos M.; Steinberg, Christian

    2018-01-01

    Disease-suppressive soils are soils in which specific soil-borne plant pathogens cause only limited disease although the pathogen and susceptible host plants are both present. Suppressiveness is in most cases of microbial origin. We conducted a comparative metabarcoding analysis of the taxonomic

  1. High-density genetic map using whole-genome re-sequencing for fine mapping and candidate gene discovery for disease resistance in peanut

    Science.gov (United States)

    High-density genetic linkage maps are essential for fine mapping QTLs controlling disease resistance traits, such as early leaf spot (ELS), late leaf spot (LLS), and Tomato spotted wilt virus (TSWV). With completion of the genome sequences of two diploid ancestors of cultivated peanut, we could use ...

  2. A journey from a SSR-based low density map to a SNP-based high density map for identification of disease resistance quantitative trait loci in peanut

    Science.gov (United States)

    Mapping and identification of quantitative trait loci (QTLs) are important for efficient marker-assisted breeding. Diseases such as leaf spots and Tomato spotted wilt virus (TSWV) cause significant loses to peanut growers. The U.S. Peanut Genome Initiative (PGI) was launched in 2004, and expanded to...

  3. Inhibitory effect of Distamycin-A and a pyrazino-pyrazine derivative on tomato spotted wilt virus.

    Science.gov (United States)

    De Fazio, G; Kudamatsu, M

    1983-08-01

    Distamycin-A hydrochloride, a synthetic antibiotic, and 2,3-dihydroxy-6-bromo-pyrazino (2,3-beta) pyrazine derivative, were used against tomato spotted wilt virus (TSWV) in tobacco plants. The drugs were applied to the leaves at concentrations of 200 and 400 mg/l. The results showed that both drugs delayed virus spread within the plant, retarding the appearance of systemic symptoms. A virus recovery test, carried out on primary leaves of Phaseolus vulgaris cv. Manteiga, showed that TSWV replication was markedly inhibited by the pyrazino-pyrazine derivative at concentrations of 200 and 400 mg/l and, to a lower extent, by Dystamycin-A at 400 mg/l.

  4. Indole-3-acetic acid biosynthesis in Fusarium delphinoides strain GPK, a causal agent of Wilt in Chickpea.

    Science.gov (United States)

    Kulkarni, Guruprasad B; Sanjeevkumar, S; Kirankumar, B; Santoshkumar, M; Karegoudar, T B

    2013-02-01

    Fusarium delphinoides (Ascomycota; Nectriaceae) is an indole-3-acetic acid (IAA) producing plant pathogen and a causal agent of wilt in chickpea. The IAA biosynthetic pathway in F. delphinoides strain GPK (FDG) was examined by analyzing metabolic intermediates and by feeding experiments. Gas chromatograph (GC) analysis of FDG culture filtrates showed the presence of metabolic intermediates of indole-3-pyruvic acid (IPyA), indole-3-acetamide (IAM), and tryptamine (TRA) pathways. The different IAA biosynthetic pathways were further confirmed by identifying the presence of different enzymes of these pathways. Substrate specificity study of aromatic amino acid aminotransferase revealed that the enzyme is highly specific for tryptophan (Trp) and α-ketoglutarate (α-kg) as amino group donor and acceptor, respectively. Furthermore, the concentration-dependent effect of exogenous IAA on fungal growth was established. Low concentration of exogenous IAA increases the fungal growth and at high concentration it decreases the growth of FDG.

  5. Role in pathogenesis of two endo-beta-1,4-xylanase genes from the vascular wilt fungus Fusarium oxysporum.

    Science.gov (United States)

    Gómez-Gómez, E; Ruíz-Roldán, M C; Di Pietro, A; Roncero, M I G; Hera, C

    2002-04-01

    A gene, xyl4, whose predicted amino acid sequence shows significant homology with family 11 xylanases, was identified from the tomato vascular wilt fungus Fusarium oxysporum f. sp. lycopersici. Expression of xyl4 is induced on oat spelt xylan as the carbon source, subject to carbon catabolite repression and preferentially expressed at alkaline ambient pH. Transcript levels of xyl4 on an inducing carbon source are differentially regulated by the nature and concentration of the nitrogen source. As shown by RT-PCR, xyl4 is expressed by F. oxysporum during the entire cycle of infection on tomato plants. Targeted inactivation of xyl4 and of xyl3, a previously identified gene of F. oxysporum f. sp. lycopersici encoding a family 10 xylanase, had no detectable effect on virulence on tomato plants, demonstrating that both genes are not essential for pathogenicity.

  6. Bacterial and fungal communities of wilted Italian ryegrass silage inoculated with and without Lactobacillus rhamnosus or Lactobacillus buchneri.

    Science.gov (United States)

    Li, Y; Nishino, N

    2011-04-01

    To understand the effects of lactic acid bacteria (LAB) inoculation on fermentation products, aerobic stability and microbial communities of silage. Wilted Italian ryegrass was stored in laboratory silos with and without inoculation of Lactobacillus rhamnosus and Lactobacillus buchneri. The silos were opened after 14, 56 and 120 days and then subjected to aerobic deterioration for 7 days. Intensive alcoholic fermentation was found in untreated silage; the sum of ethanol and 2,3-butanediol content at day 14 was about 7 times higher than that of lactic and volatile fatty acids. Alcoholic fermentation was suppressed by L. rhamnosus and L. buchneri inoculation and lactic acid and acetic acid became the dominant fermentation products, respectively. Silages were deteriorated in untreated and L. rhamnosus-inoculated silages, whereas no spoilage was found in L. buchneri-inoculated silage. Enterobacteria such as Erwinia persicina, Pantoea agglomerans and Rahnella aquatilis were detected in untreated silage, whereas some of these bacteria disappeared or became faint with L. rhamnosus treatment. When silage was deteriorated, Lactobacillus brevis and Bacillus pumilus were observed in untreated and L. rhamnosus-inoculated communities, respectively. The inoculated LAB species was detectable in addition to untreated bacterial communities. Saccharomyces cerevisiae and Pichia anomala were the main fungi in untreated and L. rhamnosus-inoculated silages; however, P. anomala was not visibly seen in L. buchneri-inoculated silage either at silo opening or after exposure to air. Inoculation with L. rhamnosus can suppress alcoholic fermentation of wilted grass silage with elimination of enterobacteria at the beginning of fermentation. Addition of L. buchneri may improve aerobic stability, with distinct inhibitory effect observed on P. anomala after silo opening. Bacterial and fungal community analyses help us to understand how inoculated LAB can function to improve the fermentation and

  7. Detecting Pathogens of Verticillium Wilt in Winter Oilseed Rape Using ELISA and PCR – Comparison of the Two Methods and With Visual Stand Evaluation

    Directory of Open Access Journals (Sweden)

    Tomáš Spitzer

    2017-01-01

    Full Text Available During 2013–2015, oilseed rape samples from various locations in the Czech Republic were analysed for the presence of Verticillium wilt. Samples were evaluated in the lab using ELISA and PCR as well as by visual evaluation during the samples collection. A comparison of detection match in individual methods also was made. ELISA and PCR matched in detecting Verticillium wilt in 60 % of cases. For practical use, a higher match rate would be necessary in cases where samples were to be analysed in various laboratories using only one of these techniques. The possibility was demonstrated to use kits as well as primers not targeted specifically to just Verticillium longisporum but recording both main species on oilseed rape (V. longisporum and V. dahliae. The match rates of lab analyses with visual evaluation of stand infection were surprisingly high at 62 % for ELISA and 77 % for PCR. All three stand evaluation methods matched in 56 % of cases.

  8. DISEASES

    DEFF Research Database (Denmark)

    Pletscher-Frankild, Sune; Pallejà, Albert; Tsafou, Kalliopi

    2015-01-01

    Text mining is a flexible technology that can be applied to numerous different tasks in biology and medicine. We present a system for extracting disease-gene associations from biomedical abstracts. The system consists of a highly efficient dictionary-based tagger for named entity recognition...... of human genes and diseases, which we combine with a scoring scheme that takes into account co-occurrences both within and between sentences. We show that this approach is able to extract half of all manually curated associations with a false positive rate of only 0.16%. Nonetheless, text mining should...... not stand alone, but be combined with other types of evidence. For this reason, we have developed the DISEASES resource, which integrates the results from text mining with manually curated disease-gene associations, cancer mutation data, and genome-wide association studies from existing databases...

  9. Draft Genome Sequence of Highly Virulent Race 4/Biovar 3 of Ralstonia solanacearum CaRs_Mep Causing Bacterial Wilt in Zingiberaceae Plants in India.

    Science.gov (United States)

    Kumar, Aundy; Munjal, Vibhuti; Sheoran, Neelam; Prameela, Thekkan Puthiyaveedu; Suseelabhai, Rajamma; Aggarwal, Rashmi; Jain, Rakesh Kumar; Eapen, Santhosh J

    2017-01-05

    The genome of Ralstonia solanacearum CaRs_Mep, a race 4/biovar 3/phylotype I bacterium causing wilt in small cardamom and other Zingiberaceae plants, was sequenced. Analysis of the 5.7-Mb genome sequence will aid in better understanding of the genetic determinants of host range, host jump, survival, pathogenicity, and virulence of race 4 of R. solanacearum. Copyright © 2017 Kumar et al.

  10. Clustering and cellular distribution characteristics of virus particles of Tomato spotted wilt virus and Tomato zonate spot virus in different plant hosts.

    Science.gov (United States)

    Zhang, Zhongkai; Zheng, Kuanyu; Dong, Jiahong; Fang, Qi; Hong, Jian; Wang, Xifeng

    2016-01-19

    Tomato spotted wilt virus (TSWV) and Tomato zonate spot virus (TZSV) are the two dominant species of thrip-transmitted tospoviruses, cause significant losses in crop yield in Yunnan and its neighboring provinces in China. TSWV and TZSV belong to different serogroup of tospoviruses but induce similar symptoms in the same host plant species, which makes diagnostic difficult. We used different electron microscopy preparing methods to investigate clustering and cellular distribution of TSWV and TZSV in the host plant species. Negative staining of samples infected with TSWV and TZSV revealed that particles usually clustered in the vesicles, including single particle (SP), double particles clustering (DPC), triple particles clustering (TPC). In the immunogold labeling negative staining against proteins of TZSV, the antibodies against Gn protein were stained more strongly than the N protein. Ultrathin section and high pressure freeze (HPF)-electron microscopy preparations revealed that TSWV particles were distributed in the cisternae of endoplasmic reticulum (ER), filamentous inclusions (FI) and Golgi bodies in the mesophyll cells. The TSWV particles clustered as multiple particles clustering (MPC) and distributed in globular viroplasm or cisternae of ER in the top leaf cell. TZSV particles were distributed more abundantly in the swollen membrane of ER in the mesophyll cell than those in the phloem parenchyma cells and were not observed in the top leaf cell. However, TZSV virions were mainly present as single particle in the cytoplasm, with few clustering as MPC. In this study, we identified TSWV and TZSV particles had the distinct cellular distribution patterns in the cytoplasm from different tissues and host plants. This is the first report of specific clustering characteristics of tospoviruses particles as well as the cellular distribution of TSWV particles in the FI and globular viroplasm where as TZSV particles inside the membrane of ER. These results indicated that

  11. Laurel Wilt: a new and devastating disease of redbay caused by a fungal symbiont of the exotic redbay Ambrosia beetle

    Science.gov (United States)

    Stephen W. Fraedrich; Thomas C. Harrington; Robert J. Rabaglia

    2007-01-01

    The mysterious death of redbay Persea borbonia (L.) Spreng.) trees on Hilton Head Island, South Carolina, and surrounding areas was first reported in local newspapers in 2003. Thousands of redbays were dying in the low country of South Carolina, and by the end of 2004 officials on Hilton Head were estimating that they had lost 75-80% of the island...

  12. Differential Expression of Tomato Spotted Wilt Virus-Derived Viral Small RNAs in Infected Commercial and Experimental Host Plants

    Science.gov (United States)

    Mitter, Neena; Koundal, Vikas; Williams, Sarah; Pappu, Hanu

    2013-01-01

    Background Viral small RNAs (vsiRNAs) in the infected host can be generated from viral double-stranded RNA replicative intermediates, self-complementary regions of the viral genome or from the action of host RNA-dependent RNA polymerases on viral templates. The vsiRNA abundance and profile as well as the endogenous small RNA population can vary between different hosts infected by the same virus influencing viral pathogenicity and host response. There are no reports on the analysis of vsiRNAs of Tomato spotted wilt virus (TSWV), a segmented negative stranded RNA virus in the family Bunyaviridae, with two of its gene segments showing ambisense gene arrangement. The virus causes significant economic losses to numerous field and horticultural crops worldwide. Principal Findings Tomato spotted wilt virus (TSWV)-specific vsiRNAs were characterized by deep sequencing in virus-infected experimental host Nicotiana benthamiana and a commercial, susceptible host tomato. The total small (s) RNA reads in TSWV-infected tomato sample showed relatively equal distribution of 21, 22 and 24 nt, whereas N. benthamiana sample was dominated by 24 nt total sRNAs. The number of vsiRNA reads detected in tomato was many a magnitude (~350:1) higher than those found in N. benthamiana, however the profile of vsiRNAs in terms of relative abundance 21, 22 and 24 nt class size was similar in both the hosts. Maximum vsiRNA reads were obtained for the M RNA segment of TSWV while the largest L RNA segment had the least number of vsiRNAs in both tomato and N. benthamiana. Only the silencing suppressor, NSs, of TSWV recorded higher antisense vsiRNA with respect to the coding frame among all the genes of TSWV. Significance Details of the origin, distribution and abundance of TSWV vsiRNAs could be useful in designing efficient targets for exploiting RNA interference for virus resistance. It also has major implications toward our understanding of the differential processing of vsiRNAs in antiviral

  13. Differential expression of tomato spotted wilt virus-derived viral small RNAs in infected commercial and experimental host plants.

    Directory of Open Access Journals (Sweden)

    Neena Mitter

    Full Text Available BACKGROUND: Viral small RNAs (vsiRNAs in the infected host can be generated from viral double-stranded RNA replicative intermediates, self-complementary regions of the viral genome or from the action of host RNA-dependent RNA polymerases on viral templates. The vsiRNA abundance and profile as well as the endogenous small RNA population can vary between different hosts infected by the same virus influencing viral pathogenicity and host response. There are no reports on the analysis of vsiRNAs of Tomato spotted wilt virus (TSWV, a segmented negative stranded RNA virus in the family Bunyaviridae, with two of its gene segments showing ambisense gene arrangement. The virus causes significant economic losses to numerous field and horticultural crops worldwide. PRINCIPAL FINDINGS: Tomato spotted wilt virus (TSWV-specific vsiRNAs were characterized by deep sequencing in virus-infected experimental host Nicotiana benthamiana and a commercial, susceptible host tomato. The total small (s RNA reads in TSWV-infected tomato sample showed relatively equal distribution of 21, 22 and 24 nt, whereas N. benthamiana sample was dominated by 24 nt total sRNAs. The number of vsiRNA reads detected in tomato was many a magnitude (~350:1 higher than those found in N. benthamiana, however the profile of vsiRNAs in terms of relative abundance 21, 22 and 24 nt class size was similar in both the hosts. Maximum vsiRNA reads were obtained for the M RNA segment of TSWV while the largest L RNA segment had the least number of vsiRNAs in both tomato and N. benthamiana. Only the silencing suppressor, NSs, of TSWV recorded higher antisense vsiRNA with respect to the coding frame among all the genes of TSWV. SIGNIFICANCE: Details of the origin, distribution and abundance of TSWV vsiRNAs could be useful in designing efficient targets for exploiting RNA interference for virus resistance. It also has major implications toward our understanding of the differential processing of vsi

  14. Supplementation of native grass hay with cowpea (Vigna unguiculata hay, wilted leucaena (Leucaena leucocephala forage, wilted tagasaste (Chamaecytisus palmensis forage or a wheat middling for young Friesian x Zebu (Boran crossbred steers

    Directory of Open Access Journals (Sweden)

    Tuomo Varvikko

    1992-03-01

    Full Text Available A 100-day experiment of a randomized block design was conducted with forty Friesian x Zebu (Boran crossbred growing steers to compare the value of wheat middling, an agro-industrial by-product (diet W, cowpea (Vigna unguiculata hay (diet C, and wilted forages of leucaena (Leucaena leucocephala, diet L and tagasaste (Chamaecytisus palmensis, diet T as cattle feed. These feeds were fed daily at a level of 1.5 kg (on an air dry basis to supplement the basal diet (diet H of native hay. A mineral supplement containing 50 g bone meal and 10 g common salt was also given daily. The steers were group-fed, but during the last two weeks at the end of the experiment the animals were housed individually in feeding pens to estimate the feed intake and apparent digestibilities of the diets. The animals were weighed at the beginning of the experiment, thereafter every two weeks, and finally at the end of the experiment. The animals consumed all the offered supplements, except for tagasaste forage, of which one third remained unconsumed. The mean daily total dry matter intake during the individual feeding period ranged from 4.0 to 5.0 kg between the diets (P

  15. evaluation of enset clones against enset bacterial wilt abstract résumé

    African Journals Online (AJOL)

    jen

    Xcm inoculated enset clones in each of the experiments developed disease symptoms to various intensity levels ... animal feed and fiber (Bezuneh et al., 1967). The ... The sustainability of enset agriculture is, ... affecting enset production.

  16. Xyleborus bispinatus Reared on Artificial Media in the Presence or Absence of the Laurel Wilt Pathogen (Raffaelea lauricola).

    Science.gov (United States)

    Menocal, Octavio; Cruz, Luisa F; Kendra, Paul E; Crane, Jonathan H; Cooperband, Miriam F; Ploetz, Randy C; Carrillo, Daniel

    2018-02-28

    Like other members of the tribe Xyleborini, Xyleborus bispinatus Eichhoff can cause economic damage in the Neotropics. X. bispinatus has been found to acquire the laurel wilt pathogen Raffaelea lauricola (T. C. Harr., Fraedrich & Aghayeva) when breeding in a host affected by the pathogen. Its role as a potential vector of R. lauricola is under investigation. The main objective of this study was to evaluate three artificial media, containing sawdust of avocado ( Persea americana Mill.) and silkbay ( Persea humilis Nash.), for rearing X. bispinatus under laboratory conditions. In addition, the media were inoculated with R. lauricola to evaluate its effect on the biology of X. bispinatus . There was a significant interaction between sawdust species and R. lauricola for all media. Two of the media supported the prolific reproduction of X. bispinatus , but the avocado-based medium was generally more effective than the silkbay-based medium, regardless whether or not it was inoculated with R. lauricola . R. lauricola had a neutral or positive effect on beetle reproduction. The pathogen was frequently recovered from beetle galleries, but only from a few individuals which were reared on inoculated media, and showed limited colonization of the beetle's mycangia. Two media with lower water content were most effective for rearing X. bispinatus .

  17. Pedotransfer functions to estimate soil water content at field capacity and permanent wilting point in hot Arid Western India

    Science.gov (United States)

    Santra, Priyabrata; Kumar, Mahesh; Kumawat, R. N.; Painuli, D. K.; Hati, K. M.; Heuvelink, G. B. M.; Batjes, N. H.

    2018-04-01

    Characterization of soil water retention, e.g., water content at field capacity (FC) and permanent wilting point (PWP) over a landscape plays a key role in efficient utilization of available scarce water resources in dry land agriculture; however, direct measurement thereof for multiple locations in the field is not always feasible. Therefore, pedotransfer functions (PTFs) were developed to estimate soil water retention at FC and PWP for dryland soils of India. A soil database available for Arid Western India ( N=370) was used to develop PTFs. The developed PTFs were tested in two independent datasets from arid regions of India ( N=36) and an arid region of USA ( N=1789). While testing these PTFs using independent data from India, root mean square error (RMSE) was found to be 2.65 and 1.08 for FC and PWP, respectively, whereas for most of the tested `established' PTFs, the RMSE was >3.41 and >1.15, respectively. Performance of the developed PTFs from the independent dataset from USA was comparable with estimates derived from `established' PTFs. For wide applicability of the developed PTFs, a user-friendly soil moisture calculator was developed. The PTFs developed in this study may be quite useful to farmers for scheduling irrigation water as per soil type.

  18. Effector Gene Suites in Some Soil Isolates of Fusarium oxysporum Are Not Sufficient Predictors of Vascular Wilt in Tomato.

    Science.gov (United States)

    Jelinski, Nicolas A; Broz, Karen; Jonkers, Wilfried; Ma, Li-Jun; Kistler, H Corby

    2017-07-01

    Seventy-four Fusarium oxysporum soil isolates were assayed for known effector genes present in an F. oxysporum f. sp. lycopersici race 3 tomato wilt strain (FOL MN-25) obtained from the same fields in Manatee County, Florida. Based on the presence or absence of these genes, four haplotypes were defined, two of which represented 96% of the surveyed isolates. These two most common effector haplotypes contained either all or none of the assayed race 3 effector genes. We hypothesized that soil isolates with all surveyed effector genes, similar to FOL MN-25, would be pathogenic toward tomato, whereas isolates lacking all effectors would be nonpathogenic. However, inoculation experiments revealed that presence of the effector genes alone was not sufficient to ensure pathogenicity on tomato. Interestingly, a nonpathogenic isolate containing the full suite of unmutated effector genes (FOS 4-4) appears to have undergone a chromosomal rearrangement yet remains vegetatively compatible with FOL MN-25. These observations confirm the highly dynamic nature of the F. oxysporum genome and support the conclusion that pathogenesis among free-living populations of F. oxysporum is a complex process. Therefore, the presence of effector genes alone may not be an accurate predictor of pathogenicity among soil isolates of F. oxysporum.

  19. The NSs protein of tomato spotted wilt virus is required for persistent infection and transmission by Frankliniella occidentalis.

    Science.gov (United States)

    Margaria, P; Bosco, L; Vallino, M; Ciuffo, M; Mautino, G C; Tavella, L; Turina, M

    2014-05-01

    Tomato spotted wilt virus (TSWV) is the type member of tospoviruses (genus Tospovirus), plant-infecting viruses that cause severe damage to ornamental and vegetable crops. Tospoviruses are transmitted by thrips in the circulative propagative mode. We generated a collection of NSs-defective TSWV isolates and showed that TSWV coding for truncated NSs protein could not be transmitted by Frankliniella occidentalis. Quantitative reverse transcription (RT)-PCR and immunostaining of individual insects detected the mutant virus in second-instar larvae and adult insects, demonstrating that insects could acquire and accumulate the NSs-defective virus. Nevertheless, adults carried a significantly lower viral load, resulting in the absence of transmission. Genome sequencing and analyses of reassortant isolates showed genetic evidence of the association between the loss of competence in transmission and the mutation in the NSs coding sequence. Our findings offer new insight into the TSWV-thrips interaction and Tospovirus pathogenesis and highlight, for the first time in the Bunyaviridae family, a major role for the S segment, and specifically for the NSs protein, in virulence and efficient infection in insect vector individuals. Our work is the first to show a role for the NSs protein in virus accumulation in the insect vector in the Bunyaviridae family: demonstration was obtained for the system TSWV-F. occidentalis, arguably one of the most damaging combination for vegetable crops. Genetic evidence of the involvement of the NSs protein in vector transmission was provided with multiple approaches.

  20. Tomato Spotted Wilt Virus NSs Protein Supports Infection and Systemic Movement of a Potyvirus and Is a Symptom Determinant.

    Science.gov (United States)

    Garcia-Ruiz, Hernan; Gabriel Peralta, Sergio M; Harte-Maxwell, Patricia A

    2018-03-14

    Plant viruses are inducers and targets of antiviral RNA silencing. To condition susceptibility, most plant viruses encode silencing suppressor proteins that interfere with antiviral RNA silencing. The NSs protein is an RNA silencing suppressor in orthotospoviruses, such as the tomato spotted wilt virus (TSWV). The mechanism of RNA silencing suppression by NSs and its role in virus infection and movement are poorly understood. Here, we cloned and tagged TSWV NSs and expressed it from a GFP-tagged turnip mosaic virus (TuMV-GFP) carrying either a wild-type or suppressor-deficient (AS9) helper component proteinase (HC-Pro). When expressed in cis, NSs restored pathogenicity and promoted systemic infection of suppressor-deficient TuMV-AS9-GFP in Nicotiana benthamiana and Arabidopsis thaliana . Inactivating mutations were introduced in NSs RNA-binding domain one. A genetic analysis with active and suppressor-deficient NSs, in combination with wild-type and mutant plants lacking essential components of the RNA silencing machinery, showed that the NSs insert is stable when expressed from a potyvirus. NSs can functionally replace potyviral HC-Pro, condition virus susceptibility, and promote systemic infection and symptom development by suppressing antiviral RNA silencing through a mechanism that partially overlaps that of potyviral HC-Pro. The results presented provide new insight into the mechanism of silencing suppression by NSs and its effect on virus infection.

  1. Identification and evaluation of two diagnostic markers linked to Fusarium wilt resistance (race 4) in banana (Musa spp.).

    Science.gov (United States)

    Wang, Wei; Hu, Yulin; Sun, Dequan; Staehelin, Christian; Xin, Dawei; Xie, Jianghui

    2012-01-01

    Fusarium wilt caused by the fungus Fusarium oxysporum f. sp. cubense race 4 (FOC4) results in vascular tissue damage and ultimately death of banana (Musa spp.) plants. Somaclonal variants of in vitro micropropagated banana can hamper success in propagation of genotypes resistant to FOC4. Early identification of FOC4 resistance in micropropagated banana plantlets is difficult, however. In this study, we identified sequence-characterized amplified region (SCAR) markers of banana associated with resistance to FOC4. Using pooled DNA from resistant or susceptible genotypes and 500 arbitrary 10-mer oligonucleotide primers, 24 random amplified polymorphic DNA (RAPD) products were identified. Two of these RAPD markers were successfully converted to SCAR markers, called ScaU1001 (GenBank accession number HQ613949) and ScaS0901 (GenBank accession number HQ613950). ScaS0901 and ScaU1001 could be amplified in FOC4-resistant banana genotypes ("Williams 8818-1" and Goldfinger), but not in five tested banana cultivars susceptible to FOC4. The two SCAR markers were then used to identify a somaclonal variant of the genotype "Williams 8818-1", which lost resistance to FOC4. Hence, the identified SCAR markers can be applied for a rapid quality control of FOC4-resistant banana plantlets immediately after the in vitro micropropagation stage. Furthermore, ScaU1001 and ScaS0901 will facilitate marker-assisted selection of new banana cultivars resistant to FOC4.

  2. Development of Reverse Transcription Thermostable Helicase-Dependent DNA Amplification for the Detection of Tomato Spotted Wilt Virus.

    Science.gov (United States)

    Wu, Xinghai; Chen, Chanfa; Xiao, Xizhi; Deng, Ming Jun

    2016-11-01

    A protocol for the reverse transcription-helicase-dependent amplification (RT-HDA) of isothermal DNA was developed for the detection of tomato spotted wilt virus (TSWV). Specific primers, which were based on the highly conserved region of the N gene sequence in TSWV, were used for the amplification of virus's RNA. The LOD of RT-HDA, reverse transcriptase-loop-mediated isothermal amplification (RT-LAMP), and reverse transcriptase-polymerase chain reaction (RT-PCR) assays were conducted using 10-fold serial dilution of RNA eluates. TSWV sensitivity in RT-HDA and RT-LAMP was 4 pg RNA compared with 40 pg RNA in RT-PCR. The specificity of RT-HDA for TSWV was high, showing no cross-reactivity with other tomato and Tospovirus viruses including cucumber mosaic virus (CMV), tomato black ring virus (TBRV), tomato mosaic virus (ToMV), or impatiens necrotic spot virus (INSV). The RT-HDA method is effective for the detection of TSWV in plant samples and is a potential tool for early and rapid detection of TSWV.

  3. Evolution and structure of Tomato spotted wilt virus populations: evidence of extensive reassortment and insights into emergence processes.

    Science.gov (United States)

    Tentchev, Diana; Verdin, Eric; Marchal, Cécile; Jacquet, Monique; Aguilar, Juan M; Moury, Benoît

    2011-04-01

    Tomato spotted wilt virus (TSWV; genus Tospovirus, family Bunyaviridae) genetic diversity was evaluated by sequencing parts of the three RNA genome segments of 224 isolates, mostly from pepper and tomato crops in southern Europe. Eighty-three per cent of the isolates showed consistent clustering into three clades, corresponding to their geographical origin, Spain, France or the USA, for the three RNA segments. In contrast, the remaining 17% of isolates did not belong to the same clade for the three RNA segments and were shown to be reassortants. Among them, eight different reassortment patterns were observed. Further phylogenetic analyses provided insights into the dynamic processes of the worldwide resurgence of TSWV that, since the 1980s, has followed the worldwide dispersal of the western flower thrips (Frankliniella occidentalis) tospovirus vector. For two clades composed essentially of Old World (OW) isolates, tree topology suggested a local re-emergence of indigenous TSWV populations following F. occidentalis introductions, while it could not be excluded that the ancestors of two other OW clades were introduced from North America contemporarily with F. occidentalis. Finally, estimation of the selection intensity that has affected the evolution of the NSs and nucleocapsid proteins encoded by RNA S of TSWV suggests that the former could be involved in the breakdown of resistance conferred by the Tsw gene in pepper.

  4. Accounting for biotic spatial variability in fields: Case of resistance screening against sunflower Verticillium wilt.

    Science.gov (United States)

    Missonnier, Hélène; Jacques, Alban; Bang, JiSu; Daydé, Jean; Mirleau-Thebaud, Virginie

    2017-01-01

    In breeding for disease resistance, the magnitude of the genetic response is difficult to appreciate because of environmental stresses that interact with the plant genotype. We discuss herein the fundamental problems in breeding for disease resistance with the aim being to better understand the interactions between plant, pathogen, and spatial patterns. The goal of this study is to fine tune breeding decisions by incorporating spatial patterns of such biotic factors into the definition of disease-occurrence probability. We use a preexisting statistics method based on geostatistics for a descriptive analysis of biotic factors for trial quality control. The plant-population structure used for spatial-pattern analysis consists of two F1-hybrid cultivars, defined as symptomatic and asymptomatic controls with respect to the studied pathogen. The controls are inserted at specific locations to establish a grid arrangement over the field that include the F1-hybrid cultivars under evaluation. We characterize the spatial structure of the pathogen population and of the general plant environment-with undetermined but present abiotic constraints-not by using direct notation such as flower time or rainfall but by using plant behavior (i.e., leaf symptom severity, indirect notation). The analysis indicates areas with higher or lower risk of disease and reveals a correlation between the symptomatic control and the effective level of disease for sunflowers. This result suggests that the pathogen and/or abiotic components are major factors in determining the probability that a plant develops the disease, which could lead to a misinterpretation of plant resistance.

  5. Goss’s wilt incidence in sweet corn is independent of transgenic traits and glyphosate

    Science.gov (United States)

    Recently claims have been made that the use of glyphosate and transgenic crop traits increases the risk of plant diseases. Transgenic traits used widely for years in dent corn are now available in commercial sweet corn cultivars, specifically, the combination of glyphosate resistance (GR) and Lepid...

  6. Isolations from the redbay ambrosia beetle, Xyleborus glabratus, confirm that the laurel wilt pathogen, Raffaelea lauricola, originated in Asia.

    Science.gov (United States)

    Harrington, Thomas C; Yun, Hye Young; Lu, Sheng-Shan; Goto, Hideaki; Aghayeva, Dilzara N; Fraedrich, Stephen W

    2011-01-01

    The laurel wilt pathogen Raffaelea lauricola was hypothesized to have been introduced to the southeastern USA in the mycangium of the redbay ambrosia beetle, Xyleborus glabratus, which is native to Asia. To test this hypothesis adult X. glabratus were trapped in Taiwan and on Kyushu Island, Japan, in 2009, and dead beetles were sent to USA for isolation of fungal symbionts. Individual X. glabratus were macerated in glass tissue grinders, and the slurry was serially diluted and plated onto malt agar medium amended with cycloheximide, a medium semiselective for Ophiostoma species and their anamorphs, including members of Raffaelea. R. lauricola was isolated from 56 of 85 beetles in Taiwan and 10 of 16 beetles in Japan at up to an estimated 10 000 CFUs per beetle. The next most commonly isolated species was R. ellipticospora, which also has been recovered from X. glabratus trapped in the USA, as were two other fungi isolated from beetles in Taiwan, R. fusca and R. subfusca. Three unidentified Raffaelea spp. and three unidentified Ophiostoma spp. were isolated rarely from X. glabratus collected in Taiwan. Isolations from beetles similarly trapped in Georgia, USA, yielded R. lauricola and R. ellipticospora in numbers similar to those from beetles trapped in Taiwan and Japan. The results support the hypothesis that R. lauricola was introduced into the USA in mycangia of X. glabratus shipped to USA in solid wood packing material from Asia. However differences in the mycangial mycoflora of X. glabratus in Taiwan, Japan and USA suggest that the X. glabratus population established in USA originated in another part of Asia.

  7. Manuka oil and phoebe oil are attractive baits for Xyleborus glabratus (Coleoptera: Scolytinae), the vector of laurel wilt.

    Science.gov (United States)

    Hanula, James L; Sullivan, Brian

    2008-12-01

    Redbay ambrosia beetle, Xyleborus glabratus Eichhoff, is a native of Southeast Asia recently established in coastal forests of Georgia, SC and Florida. It vectors a wilt fungus, Raffaelea sp., lethal to redbay trees, Persea borbonia L. Spreng, and certain other Lauraceae. No practical monitoring system exists for this beetle so we conducted studies to identify host attractants and develop lures. Volatiles were collected from redbay wood and bark by steam distillation, direct solvent extraction, and dynamic headspace sampling with a Poropak Q cartridge. Steam, methanol, and pentane extracts were tested as baits in trapping trials but were not attractive to X. glabratus. Major constituents in Poropak aerations identified by gas chromatography-mass spectrometry included alpha-pinene, beta-pinene, delta-3-carene, eucalyptol, p-cymene, alpha-copaene, terpinene-4-ol, linalool, calamenene, and nonanoic acid. We assayed several of these compounds (including eucalyptol, p-cymene, terpinene-4-ol, linalool, nonanoic acid, and caryophyllene oxide) both individually and in combination, but none were attractive at tested doses. Two other redbay odor components, alpha-copaene and calamenene, were unavailable in sufficient quantities commercially so we substituted manuka oil, the essential oil extracted from Leptospermum scoparium Forst. and Forst., which contains high proportions of both compounds. Manuka oil was equally attractive as redbay wood to X. glabratus, but increasing release rates >10-fold did not enhance its activity. Phoebe oil, an extract of Brazilian walnut (Phoebe porosa Mez.), which contains significant quantities of alpha-copaene and calamenene, was also attractive. Fractions of manuka oil were not more attractive than the whole oil. Manuka and phoebe oil are readily available and are good alternatives to redbay wood as a trap bait for monitoring X. glabratus distribution and population trends.

  8. Starch Hydrolysis and Vessel Occlusion Related to Wilt Symptoms in Olive Stems of Susceptible Cultivars Infected by Verticillium dahliae

    Science.gov (United States)

    Trapero, Carlos; Alcántara, Esteban; Jiménez, Jaime; Amaro-Ventura, María C.; Romero, Joaquín; Koopmann, Birger; Karlovsky, Petr; von Tiedemann, Andreas; Pérez-Rodríguez, Mario; López-Escudero, Francisco J.

    2018-01-01

    This study investigated starch content, amount of pathogen DNA and density of occluded vessels in healthy and Verticillium dahliae infected olive shoots and stems. Starch hydrolysis is considered a mechanism to refill xylem vessels that suffered cavitation by either, drought conditions or pathogen infections. The main objective of this work was to evaluate this mechanism in olive plants subjected to V. dahliae infection or to drought conditions, in order to know the importance of cavitation in the development of wilting symptoms. In initial experiments starch content in the shoots was studied in trees of cultivars differing in the level of resistance growing in fields naturally infested with V. dahliae. The starch content, esteemed by microscopic observation of stem transversal sections stained with lugol, decreased with the level of symptom severity. Results were confirmed in a new experiment developed with young plants of cultivars ‘Picual’ (highly susceptible), ‘Arbequina’ (moderately susceptible) and ‘Frantoio’ (resistant), growing in pots under greenhouse conditions, either inoculated or not with V. dahliae. In this experiment, the pathogen DNA content, quantified by real-time PCR, and the density of occluded vessels, recorded by microscopic observations of transversal sections stained with toluidine blue, were related to the symptoms severity caused by the pathogen. Finally, a drought experiment was established with young plants of the cultivar ‘Picual’ grown in pots under greenhouse conditions in order to compare the effects caused by water deficit with those caused by the pathogen infection. In both cases, results show that starch hydrolysis occurred, what indirectly evidence the importance of xylem cavitation in the development of the symptoms caused by V. dahliae but in the water stressed plants no vessel occlusion was detected. PMID:29445388

  9. Starch Hydrolysis and Vessel Occlusion Related to Wilt Symptoms in Olive Stems of Susceptible Cultivars Infected by Verticillium dahliae

    Directory of Open Access Journals (Sweden)

    Carlos Trapero

    2018-01-01

    Full Text Available This study investigated starch content, amount of pathogen DNA and density of occluded vessels in healthy and Verticillium dahliae infected olive shoots and stems. Starch hydrolysis is considered a mechanism to refill xylem vessels that suffered cavitation by either, drought conditions or pathogen infections. The main objective of this work was to evaluate this mechanism in olive plants subjected to V. dahliae infection or to drought conditions, in order to know the importance of cavitation in the development of wilting symptoms. In initial experiments starch content in the shoots was studied in trees of cultivars differing in the level of resistance growing in fields naturally infested with V. dahliae. The starch content, esteemed by microscopic observation of stem transversal sections stained with lugol, decreased with the level of symptom severity. Results were confirmed in a new experiment developed with young plants of cultivars ‘Picual’ (highly susceptible, ‘Arbequina’ (moderately susceptible and ‘Frantoio’ (resistant, growing in pots under greenhouse conditions, either inoculated or not with V. dahliae. In this experiment, the pathogen DNA content, quantified by real-time PCR, and the density of occluded vessels, recorded by microscopic observations of transversal sections stained with toluidine blue, were related to the symptoms severity caused by the pathogen. Finally, a drought experiment was established with young plants of the cultivar ‘Picual’ grown in pots under greenhouse conditions in order to compare the effects caused by water deficit with those caused by the pathogen infection. In both cases, results show that starch hydrolysis occurred, what indirectly evidence the importance of xylem cavitation in the development of the symptoms caused by V. dahliae but in the water stressed plants no vessel occlusion was detected.

  10. Modified expression of alternative oxidase in transgenic tomato and petunia affects the level of tomato spotted wilt virus resistance.

    Science.gov (United States)

    Ma, Hao; Song, Congfeng; Borth, Wayne; Sether, Diane; Melzer, Michael; Hu, John

    2011-10-20

    Tomato spotted wilt virus (TSWV) has a very wide host range, and is transmitted in a persistent manner by several species of thrips. These characteristics make this virus difficult to control. We show here that the over-expression of the mitochondrial alternative oxidase (AOX) in tomato and petunia is related to TSWV resistance. The open reading frame and full-length sequence of the tomato AOX gene LeAox1au were cloned and introduced into tomato 'Healani' and petunia 'Sheer Madness' using Agrobacterium-mediated transformation. Highly expressed AOX transgenic tomato and petunia plants were selfed and transgenic R1 seedlings from 10 tomato lines and 12 petunia lines were used for bioassay. For each assayed line, 22 to 32 tomato R1 progeny in three replications and 39 to 128 petunia progeny in 13 replications were challenged with TSWV. Enzyme-Linked Immunosorbent Assays showed that the TSWV levels in transgenic tomato line FKT4-1 was significantly lower than that of wild-type controls after challenge with TSWV. In addition, transgenic petunia line FKP10 showed significantly less lesion number and smaller lesion size than non-transgenic controls after inoculation by TSWV. In all assayed transgenic tomato lines, a higher percentage of transgenic progeny had lower TSWV levels than non-transgenic plants after challenge with TSWV, and the significantly increased resistant levels of tomato and petunia lines identified in this study indicate that altered expression levels of AOX in tomato and petunia can affect the levels of TSWV resistance.

  11. Modified expression of alternative oxidase in transgenic tomato and petunia affects the level of tomato spotted wilt virus resistance

    Directory of Open Access Journals (Sweden)

    Ma Hao

    2011-10-01

    Full Text Available Abstract Background Tomato spotted wilt virus (TSWV has a very wide host range, and is transmitted in a persistent manner by several species of thrips. These characteristics make this virus difficult to control. We show here that the over-expression of the mitochondrial alternative oxidase (AOX in tomato and petunia is related to TSWV resistance. Results The open reading frame and full-length sequence of the tomato AOX gene LeAox1au were cloned and introduced into tomato 'Healani' and petunia 'Sheer Madness' using Agrobacterium-mediated transformation. Highly expressed AOX transgenic tomato and petunia plants were selfed and transgenic R1 seedlings from 10 tomato lines and 12 petunia lines were used for bioassay. For each assayed line, 22 to 32 tomato R1 progeny in three replications and 39 to 128 petunia progeny in 13 replications were challenged with TSWV. Enzyme-Linked Immunosorbent Assays showed that the TSWV levels in transgenic tomato line FKT4-1 was significantly lower than that of wild-type controls after challenge with TSWV. In addition, transgenic petunia line FKP10 showed significantly less lesion number and smaller lesion size than non-transgenic controls after inoculation by TSWV. Conclusion In all assayed transgenic tomato lines, a higher percentage of transgenic progeny had lower TSWV levels than non-transgenic plants after challenge with TSWV, and the significantly increased resistant levels of tomato and petunia lines identified in this study indicate that altered expression levels of AOX in tomato and petunia can affect the levels of TSWV resistance.

  12. Greenhouse evaluation of Bacillus subtilis AP-01 and Trichoderma harzianum AP-001 in controlling tobacco diseases.

    Science.gov (United States)

    Maketon, Monchan; Apisitsantikul, Jirasak; Siriraweekul, Chatchai

    2008-04-01

    Two biological control agents, Bacillus subtilis AP-01 (Larminar(™)) and Trichoderma harzianum AP-001 (Trisan(™)) alone or/in combination were investigated in controlling three tobacco diseases, including bacterial wilt (Ralstonia solanacearum), damping-off (Pythium aphanidermatum), and frogeye leaf spot (Cercospora nicotiana). Tests were performed in greenhouse by soil sterilization prior to inoculation of the pathogens. Bacterial-wilt and damping off pathogens were drenched first and followed with the biological control agents and for comparison purposes, two chemical fungicides. But for frogeye leaf spot, which is an airborne fungus, a spraying procedure for every treatment including a chemical fungicide was applied instead of drenching. Results showed that neither B. subtilis AP-01 nor T harzianum AP-001 alone could control the bacterial wilt, but when combined, their controlling capabilities were as effective as a chemical treatment. These results were also similar for damping-off disease when used in combination. In addition, the combined B. subtilis AP-01 and T. harzianum AP-001 resulted in a good frogeye leaf spot control, which was not significantly different from the chemical treatment.

  13. Control of tomato bacterial wilt through the incorporation of aerial part of pigeon pea and crotalaria to soil Controle da murcha bacteriana do tomateiro pela incorporação da parte aérea de guandu e crotalária no solo

    Directory of Open Access Journals (Sweden)

    Suane C. Cardoso

    2006-03-01

    Full Text Available The use of organic matter that improves the physical, chemical and biological soil properties has been studied as an inducer of suppressiveness to soilborne plant pathogens. The objective of this work was to evaluate the effect of different sources and concentrations of organic matter on tomato bacterial wilt control. Two commercially available organic composts and freshly cut aerial parts of pigeon pea (Cajanus cajan and crotalaria (Crotalaria juncea were incorporated, in concentrations of 10, 20 and 30 % (v/v, into soil infested with Ralstonia solanacearum. The soil with the fresh organic matter of pigeon pea and crotalaria was incubated for 30 and 60 days before planting. Tomato seedlings of cv. Santa Clara were transplanted into polyethylene bags with 3 kg of the planting substrate (infested soil + organic matter. The wilting symptoms and percentage of flowering plants were evaluated for 45 days. All evaluated concentrations with incorporation and incubation for 30 days of aerial parts of pigeon pea and crotalaria controlled 100% tomato bacterial wilt. With 60 days of incubation, only the 10 % concentration of pigeon pea and crotalaria did not control the disease. These results suggest that soil incorporation of fresh aerial parts of pigeon pea and crotalaria is an effective method for bacterial wilt control.A utilização de materiais orgânicos que melhoram as características físicas, químicas e biológicas do solo vem sendo estudada como indutora de supressividade a fitopatógenos habitantes do solo. Este trabalho teve como objetivo avaliar o efeito de diferentes fontes e concentrações de matéria orgânica no controle da murcha bacteriana do tomateiro. Foram avaliados dois compostos orgânicos comerciais e a matéria fresca cortada da parte aérea de guandu (Cajanus cajan e de crotalária (Crotalaria juncea, nas concentrações 10, 20 e 30 % (v/v, incorporados no solo infestado com Ralstonia solanacearum. O solo que recebeu a parte

  14. Transgenic Cavendish bananas with resistance to Fusarium wilt tropical race 4.

    Science.gov (United States)

    Dale, James; James, Anthony; Paul, Jean-Yves; Khanna, Harjeet; Smith, Mark; Peraza-Echeverria, Santy; Garcia-Bastidas, Fernando; Kema, Gert; Waterhouse, Peter; Mengersen, Kerrie; Harding, Robert

    2017-11-14

    Banana (Musa spp.) is a staple food for more than 400 million people. Over 40% of world production and virtually all the export trade is based on Cavendish banana. However, Cavendish banana is under threat from a virulent fungus, Fusarium oxysporum f. sp. cubense tropical race 4 (TR4) for which no acceptable resistant replacement has been identified. Here we report the identification of transgenic Cavendish with resistance to TR4. In our 3-year field trial, two lines of transgenic Cavendish, one transformed with RGA2, a gene isolated from a TR4-resistant diploid banana, and the other with a nematode-derived gene, Ced9, remain disease free. Transgene expression in the RGA2 lines is strongly correlated with resistance. Endogenous RGA2 homologs are also present in Cavendish but are expressed tenfold lower than that in our most resistant transgenic line. The expression of these homologs can potentially be elevated through gene editing, to provide non-transgenic resistance.

  15. Browse Title Index

    African Journals Online (AJOL)

    Items 201 - 250 of 323 ... Olusola Olufunmilayo Arowolo, Adewale Abolore Ogunrombi, Samuel Olusegun Apantaku, Stephen Oluseun Adeogun. Vol 21, No 2 (2017), Perception of Mealybug Wilt Effect and Management among Pineapple Farmers in Ghana, Abstract PDF. Tutu Mark Sarpong, Elvis Asare-Bediako, Lawrence ...

  16. Enterobacter mori sp. nov., associated with bacterial wilt on Morus alba L.

    Science.gov (United States)

    Zhu, Bo; Lou, Miao-Miao; Xie, Guan-Lin; Wang, Guo-Fen; Zhou, Qin; Wang, Fang; Fang, Yuan; Su, Ting; Li, Bin; Duan, Yong-Pin

    2011-11-01

    Two isolates of mulberry-pathogenic bacteria isolated from diseased mulberry roots were investigated in a polyphasic taxonomic study. Comparative 16S rRNA gene sequence analysis combined with rpoB gene sequence analysis allocated strains R18-2(T) and R3-3 to the genus Enterobacter, with Enterobacter asburiae, E. amnigenus, E. cancerogenus, E. cloacae subsp. cloacae, E. cloacae subsp. dissolvens and E. nimipressuralis as their closest relatives. Cells of the isolates were Gram-negative, facultatively anaerobic rods, 0.3-1.0 µm wide and 0.8-2.0 µm long, with peritrichous flagella, showing a DNA G+C content of 55.1 ± 0.5 mol%. Calculation of a similarity index based on phenotypic features and fatty acid methyl ester (FAME) analysis suggested that these isolates are members of E. cancerogenus or E. asburiae or a closely related species. Biochemical data revealed that the isolates could be differentiated from their nearest neighbours by the presence of lysine decarboxylase activity and their ability to utilize d-arabitol. DNA-DNA relatedness also distinguished the two isolates from phylogenetically closely related Enterobacter strains. Based on these data, it is proposed that the isolates represent a novel species of the genus Enterobacter, named Enterobacter mori sp. nov. The type strain is R18-2(T) ( = CGMCC 1.10322(T) = LMG 25706(T)).

  17. Production, Survival, and Evaluation of Solid-Substrate Inocula of Penicillium oxalicum, a Biocontrol Agent Against Fusarium Wilt of Tomato.

    Science.gov (United States)

    Larena, I; Melgarejo, P; De Cal, A

    2002-08-01

    ABSTRACT Production of conidia of Penicillium oxalicum (ATCC number pending), a biocontrol agent of Fusarium oxysporum f. sp. lycopersici, was tested in liquid and solid fermentation. P. oxalicum produced 250-fold more conidia in solid than in liquid fermentation at 30 days after inoculation of substrate. Solid fermentation was carried out in plastic bags (600 cm(3)) especially designed for solid fermentation (VALMIC) containing 50 g of peat/vermiculite (PV) (1:1, wt/wt) with 40% moisture, sealed, sterilized, and then inoculated with 1 ml of a conidial suspension of P. oxalicum (10(5) conidia g(-1) dry substrate), sealed again, and incubated in darkness at 20 to 25 degrees C for 30 days. Addition of amendments to PV in a proportion of 0.5 (wt/wt) significantly increased conidial production of P. oxalicum. The best production was obtained on PV plus meal of cereal grains (barley) or leguminous seeds (lentil) (100-fold higher). Conidial production obtained after 5 days of inoculation was similar to that obtained at 30 days. However, viability of conidia produced in PV plus lentil meal was 35% higher than that of conidia produced in PV plus barley meal. Changes in proportions (1:1:0.5, wt/wt/wt; 1:1:1, wt/wt/wt; 1:0.5:0.5, wt/wt/wt; 1:1:0.5, vol/vol/vol) of components of the substrate (peat/vermiculite/lentil meal) did not enhance production or viability of conidia. Optimal initial moisture in the substrate was 30 to 40%. At lower moistures, significant reductions of production of conidia were observed, particularly at 10%. There was a general decline in the number of conidia in bags with time of storage at -80, -20, 4, and 25 degrees C, or at room temperature (range from 30 to 15 degrees C), with the highest decline occurring from 60 to 180 days. Conidial viability also was reduced with time, except for conidia stored at -20 degrees C. Fresh conidia produced in solid fermentation system or those conidia stored at -20 degrees C for 180 days reduced Fusarium wilt of

  18. Fusarium-induced diseases of tropical, perennial crops.

    Science.gov (United States)

    Ploetz, Randy C

    2006-06-01

    ABSTRACT The world's oldest ecosystems are found in the tropics. They are diverse, highly evolved, but barely understood. This and subsequent papers describe diseases of tropical, perennial plants that are caused by Fusarium spp. Many of these are economically significant, difficult to manage, and of scientific interest. Some represent coevolved patho-systems (e.g., Panama disease, tracheomycosis of coffee, fusariosis of pineapple, and Fusarium wilt of oil palm), whereas others may be new-encounter diseases or are caused by generalist pathogens (cushion gall of cacao). New vector relationships are evident in other pathosystems (e.g., mango malformation), and two or more pathogens have been shown to cause some of the diseases (Panama disease and tracheomycosis of coffee). More work on these pathosystems is warranted as they could reveal much about the evolution of plant pathogens and the important diseases they cause.

  19. Virus diseases in lettuce in the Mediterranean basin.

    Science.gov (United States)

    Moreno, Aranzazu; Fereres, Alberto

    2012-01-01

    Lettuce is frequently attacked by several viruses causing disease epidemics and considerable yield losses along the Mediterranean basin. Aphids are key pests and the major vectors of plant viruses in lettuce fields. Lettuce mosaic virus (LMV) is probably the most important because it is seed-transmitted in addition to be transmissible by many aphid species that alight on the crop. Tomato spotted wilt virus (TSWV) is another virus that causes severe damage since the introduction of its major vector, the thrips Frankliniella occidentalis. In regions with heavy and humid soils, Lettuce Mirafiori big-vein virus (LMBVV) can also produce major yield losses. Copyright © 2012 Elsevier Inc. All rights reserved.

  20. [Genetic improvement of cotton varieties in Huang-Huai region in China since 1950's. III. Improvement on agronomy properties, disease resistance and stability].

    Science.gov (United States)

    Jiang, B G; Kong, F L; Zhang, Q Y; Yang, F X; Jiang, R Q

    2000-01-01

    Data from a set of 5-location and 2-year experiments on 10 representative historical cotton varieties and the data of Huang-Huai Regional Cotton Trials from 1973 to 1996 were analyzed to estimate the effects of genetic improvement in agronomy properties, disease resistance and stability of cotton in Huang-Huai Region in China. The results indicated that a great genetic progress of earliness and disease resistance had been achieved by breeding programs since 1950's. The maturity was shortened 3-5 days; The rate of preforst yield was increased about 7 percentages. The problem of resistance to Fususium wilt has been solved and the resistance to Verticillum wilt was improving. Some progress in stability of cotton varieties also has been achieved by breeding programs since 1950.

  1. Survey of diseases caused by Fusarium spp. on palm trees in the Canary Islands

    Directory of Open Access Journals (Sweden)

    Julio Hernández-Hernández

    2010-05-01

    Full Text Available Between 2006 and 2007, palm trees growing in both gardens and public parks and natural palm groves in the Canary Islands (Spain, and showing symptoms of wilt and dieback, were surveyed. Isolates were recovered from affected tissues of the crowns, leaves and vascular fragments on potato dextrose agar (PDA. After incubation, the Fusarium spp. colonies recovered were single-spored. They were transferred to PDA and Spezieller Nahrstoffarmer Agar (SNA for morphological identification. Identification of Fusarium oxysporum f. sp. Canariensis was confirmed by PCR with the specific primers HK66 and HK67, which amplified a fragment of 567 bp. Fusarium wilt caused by F. oxysporum f. sp. canariensis was found on 54 Phoenix canariensis trees growing on four islands: Gran Canaria, Fuerteventura, La Palma and Tenerife. F. proliferatum occurred on fifteen palms (10 P. canariensis, 1 P. dactylifera, 3 Roystonea regia and 1 Veitchia joannis located in Gran Canaria, Fuerteventura and Tenerife. Both these Fusarium species were found only in diseased palms from gardens and public parks, but not in natural palm groves. The results show that Fusarium wilt of P. canariensis is common in the Canary Islands and for the first time report F. proliferatum affecting different palm species in those islands.

  2. FRACIONAMENTO DE PROTEÍNAS DE SILAGEM DE CAPIM-ELEFANTE EMURCHECIDO OU COM FARELO DE CACAU PROTEIN FRACTIONING OF SILAGE OF ELEPHANTGRASS WILTED OR WITH COCOA MEAL

    Directory of Open Access Journals (Sweden)

    Gleidson Giordano Pinto de Carvalho

    2008-10-01

    Full Text Available

    Desenvolveu-se o experimento para determinar as frações que compõem as proteínas da silagem de capim-elefante (Pennisetum purpureum Schum. cv. Camaroon submetido ao emurchecimento ou à adição de diferentes níveis de farelo de cacau. O capim-elefante utilizado foi colhido aos 50 dias de rebrota após o corte de uniformização e submetido aos seguintes tratamentos: capim-elefante emurchecido ao sol por oito horas, e capim-elefante sem emurchecimento com níveis de 0 %, 7 %, 14%, 21 % e 28 % de farelo de cacau (FC (% da matéria natural. Acondicionou-se o material em silos de PVC com capacidade para 5,3 litros, que foram abertos após 45 dias. Para todas as frações de proteínas estimadas, o tratamento emurchecido apresentou valores semelhantes (P>0,05 ao do tratamento sem emurchecimento. As frações protéicas foram influenciadas pelas adições de FC, verificando-se redução dos teores das frações A e B1+B2 e aumentos das frações B3 e C, para os níveis crescentes de FC.

    PALAVRAS-CHAVES: Conservação de forragens, forrageira, Pennisetum purpureum Schum. cv. Cameroon, subproduto, Theobroma cacao L.

    The experiment was conducted to determine the fractions that compose the protein of silage on the submitted elephant grass forage to wilting under the sun light for eight hours. Other treatments involved the same elephant grass without exposing to sun light but with addition of 0, 7, 14, 21, and 28% of cocoa meal (CM at the ensilage processing. The PVC silos used in the experiment were 5.3 liters in capacity, and were opened in 45 days. To all protein-estimated fractions, the wilted treatment showed similar values (P>.05 to the treatment without wilting. The protein fractions were influenced by CM addictions, verifying reduction in contents of A and B1+B2 fractions and increase in B3 and C fractions, with CM increasing levels

  3. Efeito da solarização e biofumigação, durante o outono, na incidência de murcha-bacteriana e produtividade da batata Effect of soil solarization and biofumigation during autumn on bacterial wilt incidence and potato yield

    Directory of Open Access Journals (Sweden)

    Mírian Josefina Baptista

    2006-03-01

    Full Text Available A murcha-bacteriana causada por Ralstonia solanacearum é uma das principais doenças da cultura da batata. A solarização tem sido estudada como opção para a desinfestação do solo e tem potencial para o controle da murcha bacteriana. A técnica é indicada para uso nas estações quentes do ano pois depende de condições climáticas adequadas. Devido ao período de plantio de determinadas culturas, é interessante avaliar o uso da solarização em outras épocas do ano e associada a outras técnicas para garantir sua eficiência. A biofumigação é a desinfestação do solo através da adição de matéria orgânica que, durante sua decomposição, libera substâncias tóxicas aos fitopatógenos. Neste trabalho avaliou-se durante o outono (maio a junho os efeitos da adição de cama de aves (biofumigação e da solarização na incidência natural da murcha-bacteriana e na produtividade da batata, através dos tratamentos: adição de cama de aves (20 t/ha, uréia (100 kg/ha, aplicação de brometo de metila e solo sem tratamento (testemunha, todos solarizados ou não solarizados. Avaliou-se a produção de tubérculos totais e comerciais e, a partir da incidência de murcha-bacteriana, foi feito o cálculo da área abaixo da curva de progresso da doença (AACPD. Na área infestada, apenas o uso do brometo de metila proporcionou reduções significativas na incidência da murcha-bacteriana. No entanto, a aplicação de brometo de metila e a adição de cama de aves em associação com a solarização possibilitaram produção significativamente maior de tubérculos de batata em relação à testemunha. Os efeitos da solarização associada à biofumigação com cama de aves sobre a produtividade da batata em área infestada com R. solanacearum devem ser melhor investigados.Bacterial wilt caused by Ralstonia solanacearum is one of the most important diseases of the potato. Soil solarization has been studied as an option for soilborne

  4. Ecology, Epidemiology and Disease Management of Ralstonia syzygii in Indonesia.

    Science.gov (United States)

    Safni, Irda; Subandiyah, Siti; Fegan, Mark

    2018-01-01

    Ralstonia solanacearum species complex phylotype IV strains, which have been primarily isolated from Indonesia, Australia, Japan, Korea, and Malaysia, have undergone recent taxonomic and nomenclatural changes to be placed in the species Ralstonia syzygii . This species contains three subspecies; Ralstonia syzygii subsp. syzygii , a pathogen causing Sumatra disease of clove trees in Indonesia, Ralstonia syzygii subsp. indonesiensis , the causal pathogen of bacterial wilt disease on a wide range of host plants, and Ralstonia syzygii subsp. celebesensis , the causal pathogen of blood disease on Musa spp. In Indonesia, these three subspecies have devastated the cultivation of susceptible host plants which have high economic value. Limited knowledge on the ecology and epidemiology of the diseases has hindered the development of effective control strategies. In this review, we provide insights into the ecology, epidemiology and disease control of these three subspecies of Ralstonia syzygii .

  5. The silencing suppressor (NSs) protein of the plant virus Tomato spotted wilt virus enhances heterologous protein expression and baculovirus pathogenicity in cells and lepidopteran insects.

    Science.gov (United States)

    de Oliveira, Virgínia Carla; da Silva Morgado, Fabricio; Ardisson-Araújo, Daniel Mendes Pereira; Resende, Renato Oliveira; Ribeiro, Bergmann Morais

    2015-11-01

    In this work, we showed that cell death induced by a recombinant (vAcNSs) Autographa californica multiple nucleopolyhedrovirus (AcMNPV) expressing the silencing suppressor (NSs) protein of Tomato spotted wilt virus (TSWV) was enhanced on permissive and semipermissive cell lines. The expression of a heterologous gene (firefly luciferase) during co-infection of insect cells with vAcNSs and a second recombinant baculovirus (vAgppolhfluc) was shown to increase when compared to single vAgppolhfluc infections. Furthermore, the vAcNSs mean time-to-death values were significantly lower than those for wild-type AcMNPV on larvae of Spodoptera frugiperda and Anticarsia gemmatalis. These results showed that the TSWV-NSs protein could efficiently increase heterologous protein expression in insect cells as well as baculovirus pathogenicity and virulence, probably by suppressing the gene-silencing machinery in insects.

  6. Analysis of Tomato spotted wilt virus NSs protein indicates the importance of the N-terminal domain for avirulence and RNA silencing suppression.

    Science.gov (United States)

    de Ronde, Dryas; Pasquier, Adrien; Ying, Su; Butterbach, Patrick; Lohuis, Dick; Kormelink, Richard

    2014-02-01

    Recently, Tomato spotted wilt virus (TSWV) nonstructural protein NSs has been identified unambiguously as an avirulence (Avr) determinant for Tomato spotted wilt (Tsw)-based resistance. The observation that NSs from two natural resistance-breaking isolates had lost RNA silencing suppressor (RSS) activity and Avr suggested a link between the two functions. To test this, a large set of NSs mutants was generated by alanine substitutions in NSs from resistance-inducing wild-type strains (NSs(RI) ), amino acid reversions in NSs from resistance-breaking strains (NSs(RB)), domain deletions and swapping. Testing these mutants for their ability to suppress green fluorescent protein (GFP) silencing and to trigger a Tsw-mediated hypersensitive response (HR) revealed that the two functions can be separated. Changes in the N-terminal domain were found to be detrimental for both activities and indicated the importance of this domain, additionally supported by domain swapping between NSs(RI) and NSs(RB). Swapping domains between the closely related Tospovirus Groundnut ringspot virus (GRSV) NSs and TSWV NSs(RI) showed that Avr functionality could not simply be transferred between species. Although deletion of the C-terminal domain rendered NSs completely dysfunctional, only a few single-amino-acid mutations in the C-terminus affected both functions. Mutation of a GW/WG motif (position 17/18) rendered NSs completely dysfunctional for RSS and Avr activity, and indicated a putative interaction between NSs and Argonaute 1 (AGO1), and its importance in TSWV virulence and viral counter defence against RNA interference. © 2013 BSPP AND JOHN WILEY & SONS LTD.

  7. Improvement of cassava for resistance to insect pests and diseases

    International Nuclear Information System (INIS)

    Mwanga, R.O.M.

    1997-01-01

    The African cassava mosaic virus and cassava mealybug are devastating the cassava crop in Uganda. Because of the severe widespread occurrence of the virus and mealybug, in vitro cultured cassava plantlets instead of stem cuttings will be irradiated. In addition, the project has incorporated sweet potato. Installation of tissue culture laboratory at Namulonge was completed in early 1993. Work is in progress to establish efficient in vitro culture micropropagation techniques for the two crops. Small numbers of cassava plantlets of varieties 'TMS 30337' and 'TMS 4(2)1425' and sweet potato entry 30 are in vitro culture. Mass irradiation of plantlets is planned in future. (author). 4 refs

  8. Improvement of cassava for resistance to insect pests and diseases

    Energy Technology Data Exchange (ETDEWEB)

    Mwanga, R O.M. [Namulonge Agricultural and Animal Production Research Inst., Kampala (Uganda)

    1997-12-01

    The African cassava mosaic virus and cassava mealybug are devastating the cassava crop in Uganda. Because of the severe widespread occurrence of the virus and mealybug, in vitro cultured cassava plantlets instead of stem cuttings will be irradiated. In addition, the project has incorporated sweet potato. Installation of tissue culture laboratory at Namulonge was completed in early 1993. Work is in progress to establish efficient in vitro culture micropropagation techniques for the two crops. Small numbers of cassava plantlets of varieties `TMS 30337` and `TMS 4(2)1425` and sweet potato entry 30 are in vitro culture. Mass irradiation of plantlets is planned in future. (author). 4 refs.

  9. 'CM 88' - A multiple disease resistant chickpea mutant variety

    International Nuclear Information System (INIS)

    Haq, M.A.; Hassan, Mahmudul; Sadiq, M.

    2001-01-01

    Full text: Chickpea is the most important grain legume crop of Pakistan. Ascochyta blight (Ascochyta rabiei) and Fusarium wilt (Fusarium oxysporum F. sp cicer) are most serious diseases, having the potential to devastate a crop. A multiple disease resistant and high yielding mutant CM 88 has been developed through 100 Gy gamma irradiation treatment of variety 'C 727'. This was once a widely grown and popular variety, which lost its resistance to Ascochyta and was replaced. The selection of mutants was performed in the M2 generation grown in the Ascochyta blight nursery and sixteen mutants were selected. In the subsequent generations CM 88 proved resistant to both Ascochyta blight and Fusarium wilt, and exhibited superiority in agronomic characteristics. CM 88 was also tested for many years in the various yield trials on research stations and farmers fields throughout the country. In these trials it out yielded both the parent and standard varieties. The mutant CM 88 has been approved by the Punjab Seed Council on 27 October 1994 for general cultivation in the Punjab Province, especially the Thal area which accounts for more than 70% of the area under chickpea cultivation. (author)

  10. Recovery plan for laurel wilt on redbay and other forest species caused by Raffaelea lauricola and disseminated by Xyleborus glabratus

    Science.gov (United States)

    M. A. Hughes; J.A. Smith; R. C. Ploetz; P. E. Kendra; Albert (Bud) Mayfield; James Hanula; J. Hulcr; L.L. Stelinski; S. Cameron;  J. J. Riggins; D. Carrillo; R. Rabaglia; J. Eickwort

    2015-01-01

    This recovery plan is one of several disease-specific documents produced as part of the National Plant Disease Recovery System (NPDRS) called for in Homeland Security Presidential Directive Number 9 (HSPD-9). The purpose of the NPDRS is to insure that the tools, infrastructure, communication networks, and capacity required to mitigate the impact of high-consequence...

  11. Wilt, crown, and root rot of common rose mallow (Hibiscus moscheutos) caused by a novel Fusarium sp

    Science.gov (United States)

    A new crown and root rot disease of landscape plantings of the malvaceous ornamental common rose mallow (Hibiscus moscheutos) was first detected in Washington State in 2012. The main objectives of this study were to complete Koch's postulates, document the disease sypmtoms photographically, and iden...

  12. Assessment of recent outbreaks of Dickeya sp (syn. Erwinia chrysanthemi) slow wilt in potato crops in Israel

    NARCIS (Netherlands)

    Tsror, L.; Erlich, O.; Lebiush, S.; Hazanovsky, M.; Zig, U.; Slawiak, M.; Grabe, G.; Wolf, van der J.M.; Haar, van de J.J.

    2009-01-01

    Suspected Dickeya sp. strains were obtained from potato plants and tubers collected from commercial plots. The disease was observed on crops of various cultivars grown from seed tubers imported from the Netherlands during the spring seasons of 2004-2006, with disease incidence of 2-30% ( 10% in

  13. Biology and host associations of redbay ambrosia beetle (Coleoptera: Curculionidae: Scolytinae), exotic vector of laurel wilt killing redbay trees in the southeastern United States.

    Science.gov (United States)

    Hanula, James L; Mayfield, Albert E; Fraedrich, Stephen W; Rabaglia, Robert J

    2008-08-01

    The redbay ambrosia beetle, Xyleborus glabratus Eichhoff (Coleoptera: Curculionidae: Scolytinae), and its fungal symbiont, Raffaelea sp., are new introductions to the southeastern United States responsible for the wilt of mature redbay, Persea borbonia (L.) Spreng., trees. In 2006 and 2007, we investigated the seasonal flight activity of X. glabratus, its host associations, and population levels at eight locations in South Carolina and Georgia where infestations ranged from very recent to at least several years old. Adults were active throughout the year with peak activity in early September. Brood development seems to take 50-60 d. Wood infested with beetles and infected with the Raffaelea sp. was similar in attraction to uninfested redbay wood, whereas both were more attractive than a nonhost species. Sassafras, Sassafras albidium (Nutt.) Nees, another species of Lauraceae, was not attractive to X. glabratus and very few beetle entrance holes were found in sassafras wood compared with redbay. Conversely, avocado, Persea americana Mill., was as attractive to X. glabratus as swampbay, P. palustris (Raf.) Sarg., and both were more attractive than the nonhost red maple, Acer rubrum L. However, avocado had relatively few entrance holes in the wood. In 2007, we compared X. glabratus populations in areas where all mature redbay have died to areas where infestations were very active and more recent. Trap catches of X. glabratus and numbers of entrance holes in trap bolts of redbay were correlated with the number of dead trees with leaves attached. Older infestations where mature host trees had been eliminated by the wilt had low numbers of beetles resulting in trap catches ranging from 0.04 to 0.12 beetles per trap per d compared with 4-7 beetles per trap per d in areas with numerous recently dead trees. Our results indicate beetle populations drop dramatically after suitable host material is gone and provide hope that management strategies can be developed to restore

  14. A Dehydration-Induced Eukaryotic Translation Initiation Factor iso4G Identified in a Slow Wilting Soybean Cultivar Enhances Abiotic Stress Tolerance in Arabidopsis

    Directory of Open Access Journals (Sweden)

    Juan P. Gallino

    2018-03-01

    Full Text Available Water is usually the main limiting factor for soybean productivity worldwide and yet advances in genetic improvement for drought resistance in this crop are still limited. In the present study, we investigated the physiological and molecular responses to drought in two soybean contrasting genotypes, a slow wilting N7001 and a drought sensitive TJS2049 cultivars. Measurements of stomatal conductance, carbon isotope ratios and accumulated dry matter showed that N7001 responds to drought by employing mechanisms resulting in a more efficient water use than TJS2049. To provide an insight into the molecular mechanisms that these cultivars employ to deal with water stress, their early and late transcriptional responses to drought were analyzed by suppression subtractive hybridization. A number of differentially regulated genes from N7001 were identified and their expression pattern was compared between in this genotype and TJS2049. Overall, the data set indicated that N7001 responds to drought earlier than TJ2049 by up-regulating a larger number of genes, most of them encoding proteins with regulatory and signaling functions. The data supports the idea that at least some of the phenotypic differences between slow wilting and drought sensitive plants may rely on the regulation of the level and timing of expression of specific genes. One of the genes that exhibited a marked N7001-specific drought induction profile encoded a eukaryotic translation initiation factor iso4G (GmeIFiso4G-1a. GmeIFiso4G-1a is one of four members of this protein family in soybean, all of them sharing high sequence identity with each other. In silico analysis of GmeIFiso4G-1 promoter sequences suggested a possible functional specialization between distinct family members, which can attain differences at the transcriptional level. Conditional overexpression of GmeIFiso4G-1a in Arabidopsis conferred the transgenic plants increased tolerance to osmotic, salt, drought and low

  15. Potential of Bacillus spp produces siderophores insuppressing thewilt disease of banana plants

    Science.gov (United States)

    Kesaulya, H.; Hasinu, J. V.; Tuhumury, G. NC

    2018-01-01

    In nature, different types of siderophore such as hydroxymate, catecholets and carboxylate, are produced by different bacteria. Bacillus spp were isolated from potato rhizospheric soil can produce siderophore of both catecholets and salicylate type with different concentrations. Various strains of Bacillus spp were tested for pathogen inhibition capability in a dual culture manner. The test results showed the ability of inhibition of pathogen isolated from banana wilt disease. From the result tested were found Bacillus niabensis Strain PT-32-1, Bacillus subtilis Strain SWI16b, Bacillus subtilis Strain HPC21, Bacillus mojavensis Strain JCEN3, and Bacillus subtilis Strain HPC24 showed different capabilities in suppressing pathogen.

  16. The expansion of brown rot disease throughout Bolivia: possible role of climate change.

    Science.gov (United States)

    Castillo, José Antonio; Plata, Giovanna

    2016-05-01

    Bacterial wilt is a devastating plant disease caused by the bacterial pathogen Ralstonia solanacearum species complex and affects different crops. Bacterial wilt infecting potato is also known as brown rot (BR) and is responsible for significant economic losses in potato production, especially in developing countries. In Bolivia, BR affects up to 75% of the potato crop in areas with high incidence and 100% of stored potatoes. The disease has disseminated since its introduction to the country in the mid-1980s mostly through contaminated seed tubers. To avoid this, local farmers multiply seed tubers in highlands because the strain infecting potatoes cannot survive near-freezing temperatures that are typical in the high mountains. Past disease surveys have shown an increase in seed tubers with latent infection in areas at altitudes lower than 3000 m a.s.l. Since global warming is increasing in the Andes Mountains, in this work, we explored the incidence of BR in areas at altitudes above 3000 m a.s.l. Results showed BR presence in the majority of these areas, suggesting a correlation between the increase in disease incidence and the increase in temperature and the number of irregular weather events resulting from climate change. However, it cannot be excluded that the increasing availability of latently infected seed tubers has boosted the spread of BR.

  17. Possible involvement of G-proteins and cAMP in the induction of progesterone hydroxylating enzyme system in the vascular wilt fungus Fusarium oxysporum.

    Science.gov (United States)

    Poli, Anna; Di Pietro, Antonio; Zigon, Dusan; Lenasi, Helena

    2009-02-01

    Fungi present the ability to hydroxylate steroids. In some filamentous fungi, progesterone induces an enzyme system which converts the compound into a less toxic hydroxylated product. We investigated the progesterone response in the vascular wilt pathogen Fusarium oxysporum, using mass spectrometry and high performance liquid chromatography (HPLC). Progesterone was mainly transformed into 15alpha-hydroxyprogesterone, which was found predominantly in the extracellular medium. The role of two conserved fungal signaling cascades in the induction of the progesterone-transforming enzyme system was studied, using knockout mutants lacking the mitogen-activated protein kinase Fmk1 or the heterotrimeric G-protein beta subunit Fgb1 functioning upstream of the cyclic adenosine monophosphate (cAMP) pathway. No steroid hydroxylation was induced in the Deltafgb1 strain, suggesting a role for the G-protein beta subunit in progesterone signaling. Exogenous cAMP restored the induction of progesterone-transforming activity in the Deltafgb1 strain, suggesting that steroid signaling in F. oxysporum is mediated by the cAMP-PKA pathway.

  18. Comparative analysis of chrysanthemum transcriptome in response to three RNA viruses: Cucumber mosaic virus, Tomato spotted wilt virus and Potato virus X.

    Science.gov (United States)

    Choi, Hoseong; Jo, Yeonhwa; Lian, Sen; Jo, Kyoung-Min; Chu, Hyosub; Yoon, Ju-Yeon; Choi, Seung-Kook; Kim, Kook-Hyung; Cho, Won Kyong

    2015-06-01

    The chrysanthemum is one of popular flowers in the world and a host for several viruses. So far, molecular interaction studies between the chrysanthemum and viruses are limited. In this study, we carried out a transcriptome analysis of chrysanthemum in response to three different viruses including Cucumber mosaic virus (CMV), Tomato spotted wilt virus (TSWV) and Potato virus X (PVX). A chrysanthemum 135K microarray derived from expressed sequence tags was successfully applied for the expression profiles of the chrysanthemum at early stage of virus infection. Finally, we identified a total of 125, 70 and 124 differentially expressed genes (DEGs) for CMV, TSWV and PVX, respectively. Many DEGs were virus specific; however, 33 DEGs were commonly regulated by three viruses. Gene ontology (GO) enrichment analysis identified a total of 132 GO terms, and of them, six GO terms related stress response and MCM complex were commonly identified for three viruses. Several genes functioning in stress response such as chitin response and ethylene mediated signaling pathway were up-regulated indicating their involvement in establishment of host immune system. In particular, TSWV infection significantly down-regulated genes related to DNA metabolic process including DNA replication, chromatin organization, histone modification and cytokinesis, and they are mostly targeted to nucleosome and MCM complex. Taken together, our comparative transcriptome analysis revealed several genes related to hormone mediated viral stress response and DNA modification. The identified chrysanthemums genes could be good candidates for further functional study associated with resistant to various plant viruses.

  19. A single point mutation in Tomato spotted wilt virus NSs protein is sufficient to overcome Tsw-gene-mediated resistance in pepper.

    Science.gov (United States)

    Almási, Asztéria; Nemes, Katalin; Csömör, Zsófia; Tóbiás, István; Palkovics, László; Salánki, Katalin

    2017-06-01

    The nonstructural protein (NSs) of Tomato spotted wilt virus (TSWV) was previously identified as an avirulence determinant for Tsw-based resistance on pepper. The NSs of wild-type (WT) and resistance-breaking (RB) TSWV strains isolated in Hungary had only two amino acid substitutions (104, 461). We have analysed the ability of the NSs and their point mutant variants to trigger Tsw-mediated hypersensitive responses and RNA silencing suppressor (RSS) activity in patch assays. We identified a single amino acid change at position 104 (T-A) that was responsible for the necrosis induction or loss, while a significant difference was not detected in the RSS activity of the two parental strains. We have successfully complemented the infection of the WT strain on resistant pepper cultivar with the infectious S RNA transcript of the RB strain and the WT-T104A point mutant. Our work provides direct evidence that a single amino acid change can induce an RB phenotype.

  20. Phylogenetic analysis of Tomato spotted wilt virus (TSWV) NSs protein demonstrates the isolated emergence of resistance-breaking strains in pepper.

    Science.gov (United States)

    Almási, Asztéria; Csilléry, Gábor; Csömör, Zsófia; Nemes, Katalin; Palkovics, László; Salánki, Katalin; Tóbiás, István

    2015-02-01

    Resurgence of Tomato spotted wilt virus (TSWV) worldwide as well as in Hungary causing heavy economic losses directed the attention to the factors contributing to the outbreak of this serious epidemics. The introgression of Tsw resistance gene into various pepper cultivars seemed to solve TSWV control, but widely used resistant pepper cultivars bearing the same, unique resistance locus evoked the rapid emergence of resistance-breaking (RB) TSWV strains. In Hungary, the sporadic appearance of RB strains in pepper-producing region was first observed in 2010-2011, but in 2012 it was detected frequently. Previously, the non-structural protein (NSs) encoded by small RNA (S RNA) of TSWV was verified as the avirulence factor for Tsw resistance, therefore we analyzed the S RNA of the Hungarian RB and wild type (WT) isolates and compared to previously analyzed TSWV strains with RB properties from different geographical origins. Phylogenetic analysis demonstrated that the different RB strains had the closest relationship with the local WT isolates and there is no conserved mutation present in all the NSs genes of RB isolates from different geographical origins. According to these results, we concluded that the RB isolates evolved separately in geographic point of view, and also according to the RB mechanism.

  1. Complete genome sequences of three tomato spotted wilt virus isolates from tomato and pepper plants in Korea and their phylogenetic relationship to other TSWV isolates.

    Science.gov (United States)

    Lee, Jong-Seung; Cho, Won Kyong; Kim, Mi-Kyeong; Kwak, Hae-Ryun; Choi, Hong-Soo; Kim, Kook-Hyung

    2011-04-01

    Tomato spotted wilt virus (TSWV) infects numerous host plants and has three genome segments, called L, M and S. Here, we report the complete genome sequences of three Korean TSWV isolates (TSWV-1 to -3) infecting tomato and pepper plants. Although the nucleotide sequence of TSWV-1 genome isolated from tomato is very different from those of TSWV-2 and TSWV-3 isolated from pepper, the deduced amino acid sequences of the five TSWV genes are highly conserved among all three TSWV isolates. In phylogenetic analysis, deduced RdRp protein sequences of TSWV-2 and TSWV-3 were clustered together with two previously reported isolates from Japan and Korea, while TSWV-1 grouped together with a Hawaiian isolate. A phylogenetic tree based on N protein sequences, however, revealed four distinct groups of TSWV isolates, and all three Korean isolates belonged to group II, together with many other isolates, mostly from Europe and Asia. Interestingly, most American isolates grouped together as group I. Together, these results suggested that these newly identified TSWV isolates might have originated from an Asian ancestor and undergone divergence upon infecting different host plants.

  2. Pine wilt disease in Yunnan, China: Evidence of non-local pine sawyer Monochamus alternatus (Coloptera: Cerambycidae) populations revealed by mitochondrial DNA

    Science.gov (United States)

    Da-Ying Fu; Shao-Ji Hu; Hui Ye; Robert A. Haack; Ping-Yang. Zhou

    2010-01-01

    Monochamus alternatus (Hope) specimens were collected from nine geographical populations in China,where the pinewood nematode Bursaphelenchus xylophilus (Steiner et Buhrer) was present. There were seven populations in southwestern China in Yunnan Province (Ruili,Wanding, Lianghe, Pu'er, Huaning, Stone Forest and Yongsheng),...

  3. Status of Sassafras albidum (Nutt.) Nees in the presence of laurel wilt disease and throughout the eastern United States

    Science.gov (United States)

    KaDonna C. Randolph

    2017-01-01

    Sassafras albidum (Sassafras) is an ecologically important tree species that is widely distributed throughout the eastern United States. Sassafras is presently threatened by Raffaelea lauricola, a fungus vectored by Xyleborus glabratus (Coleoptera: Curculionidae: Scolytinae; Redbay Ambrosia Beetle), which...

  4. Laurel wilt, caused by Raffaelea lauricola , is detected for the first time outside the southeastern United States

    Science.gov (United States)

    R. C. Ploetz; Y. Y. Thant; M. A. Hughes; T. J. Dreaden; J. L. Konkol; A. T. Kyaw; J. A. Smith; C. L. Harmon

    2016-01-01

    In October 2014, a survey for diseases and pests of an emerging fruit crop, avocado (Persea americana) (FAO 2000), was conducted in Southern Shan State of Myanmar (aka Burma). In the Tuanggyi District (1,400 m elevation, 20.5°N 97°E), monocultures of up to 20 ha were observed, whereas...

  5. Seasonal variation in the biocontrol efficiency of bacterial wilt is driven by temperature-mediated changes in bacterial competitive interactions

    NARCIS (Netherlands)

    Wei, Zhong; Huang, Jianfeng; Yang, Tianjie; Jousset, Alexandre; Xu, Yangchun; Shen, Qirong; Friman, Ville Petri

    2017-01-01

    Microbe-based biocontrol applications hold the potential to become an efficient way to control plant pathogen disease outbreaks in the future. However, their efficiency is still very variable, which could be due to their sensitivity to the abiotic environmental conditions. Here, we assessed how

  6. Evaluation of Suppressiveness of Soils Exhibiting Soil-Borne Disease Suppression after Long-Term Application of Organic Amendments by the Co-cultivation Method of Pathogenic Fusarium oxysporum and Indigenous Soil Microorganisms.

    Science.gov (United States)

    Mitsuboshi, Masahiro; Kioka, Yuuzou; Noguchi, Katsunori; Asakawa, Susumu

    2018-03-29

    Preventive measures against soil-borne diseases need to be implemented before cultivation because very few countermeasures are available after the development of diseases. Some soils suppress soil-borne diseases despite the presence of a high population density of pathogens. If the suppressiveness of soil against soil-borne diseases may be predicted and diagnosed for crop fields, it may be possible to reduce the labor and cost associated with excessive disinfection practices. We herein evaluated the suppressiveness of soils in fields with the long-term application of organic amendments by examining the growth of pathogenic Fusarium oxysporum co-cultivated with indigenous soil microorganisms on agar plates. Soils treated with coffee residue compost or rapeseed meal showed suppressiveness against spinach wilt disease by F. oxysporum f. sp. spinaciae or spinach wilt and lettuce root rot diseases by F. oxysporum f. sp. spinaciae and F. oxysporum f. sp. lactucae, respectively, and the growth of pathogenic Fusarium spp. on agar plates was suppressed when co-cultured with microorganisms in a suspension from these soils before crop cultivation. These results indicate the potential of the growth degree of pathogenic F. oxysporum estimated by this method as a diagnostic indicator of the suppressiveness of soil associated with the inhabiting microorganisms. A correlation was found between the incidence of spinach wilt disease in spinach and the growth degree of F. oxysporum f. sp. spinaciae by this co-cultivation method, indicating that suppressiveness induced by organic amendment applications against F. oxysporum f. sp. spinaciae is evaluable by this method. The co-cultivation method may be useful for predicting and diagnosing suppressiveness against soil-borne diseases.

  7. Características fermentativas de silagens de capim-elefante emurchecido ou com adição de farelo de cacau Fermentation characteristics of silage of elephantgrass wilted or with addition of cocoa meal

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    G.G.P. Carvalho

    2008-02-01

    Full Text Available O experimento foi realizado para avaliar as características fermentativas da silagem de capim-elefante emurchecido ou adicionado de diferentes níveis de farelo de cacau. O capim-elefante utilizado foi colhido aos 50 dias de rebrota após o corte de uniformização e submetido aos seguintes tratamentos na ensilagem: capim-elefante emurchecido ao sol por oito horas e capim-elefante sem emurchecimento adicionado de 0, 7, 14, 21 e 28% de farelo de cacau (% da matéria natural. Foram utilizadas quatro repetições por tratamento. O material foi acondicionado em silos de PVC com 0,15m de diâmetro e 0,3m de altura, adotando-se compactação de 500kg/m³. O pH reduziu e os carboidratos solúveis (CHO S aumentaram de forma linear (PThe experiment was carried out to evaluate the fermentation characteristics of eight hours sun light wilted elephant grass silage in comparison to no sun light exposed silage added by 0, 7, 14, 21, and 28% of cocoa meal during the ensilage process. PVC silos, measuring 0.15m diameter x 0.30m height, were used to ensilage the elephantgrass using a compacting pressure of 500kg/m³. Soluble carbohydrates decreased but pH and N-NH3 increased (P<0.05 as the cocoa meal level increased in the silage. No difference between wilted and no wilted elephantgrass silages was observed for organic acid content. Addition of 0, 7, 14, 21, and 28% of cocoa meal caused an increase of 2.23, 2.48, 3.14, 3.49, and 3.87% of lactic acid contents. Addition of cocoa meal during the ensilage process enhanced fermentation quality of elephantgrass silage.

  8. Development of a water-soluble preparation of emamectin benzoate and its preventative effect against the wilting of pot-grown pine trees inoculated with the pine wood nematode, Bursaphelenchus xylophilus.

    Science.gov (United States)

    Takai, K; Soejima, T; Suzuki, T; Kawazu, K

    2001-05-01

    Water-soluble preparations have been investigated to develop a trunk injection agent based on the poorly water-soluble anti-nematode emamectin benzoate. Following tests on the phytotoxicity of some solvents and solubilizers and demonstration of the ability of some solubilizers to dissolve emamectin benzoate in water, acetone + methanol was selected as the solvent and Polysorbate 80 as the solubilizer. This water-soluble preparation of emamectin benzoate prevented the wilting of pot-grown 4-year-old trees of the Japanese black pine, Pinus thunbergii, artificially inoculated with the pine wood nematode, Bursaphelenchus xylophilus, at a dose of 20 g emamectin benzoate per cubic metre of pine tree.

  9. Different mechanisms of Trichoderma virens-mediated resistance in tomato against Fusarium wilt involve the jasmonic and salicylic acid pathways.

    Science.gov (United States)

    Jogaiah, Sudisha; Abdelrahman, Mostafa; Tran, Lam-Son Phan; Ito, Shin-Ichi

    2018-04-01

    In the present study, we investigated the role of Trichoderma virens (TriV_JSB100) spores or cell-free culture filtrate in the regulation of growth and activation of the defence responses of tomato (Solanum lycopersicum) plants against Fusarium oxysporum f. sp. lycopersici by the development of a biocontrol-plant-pathogen interaction system. Two-week-old tomato seedlings primed with TriV_JSB100 spores cultured on barley grains (BGS) or with cell-free culture filtrate (CF) were inoculated with Fusarium pathogen under glasshouse conditions; this resulted in significantly lower disease incidence in tomato Oogata-Fukuju plants treated with BGS than in those treated with CF. To dissect the pathways associated with this response, jasmonic acid (JA) and salicylic acid (SA) signalling in BGS- and CF-induced resistance was evaluated using JA- and SA-impaired tomato lines. We observed that JA-deficient mutant def1 plants were susceptible to Fusarium pathogen when they were treated with BGS. However, wild-type (WT) BGS-treated tomato plants showed a higher JA level and significantly lower disease incidence. SA-deficient mutant NahG plants treated with CF were also found to be susceptible to Fusarium pathogen and displayed low SA levels, whereas WT CF-treated tomato plants exhibited moderately lower disease levels and substantially higher SA levels. Expression of the JA-responsive defensin gene PDF1 was induced in WT tomato plants treated with BGS, whereas the SA-inducible pathogenesis-related protein 1 acidic (PR1a) gene was up-regulated in WT tomato plants treated with CF. These results suggest that TriV_JSB100 BGS and CF differentially induce JA and SA signalling cascades for the elicitation of Fusarium oxysporum resistance in tomato. © 2017 BSPP AND JOHN WILEY & SONS LTD.

  10. EFFECT OF ALTITUDE AND WOUNDING ON BLOOD DISEASE PROGRESS OF PLANTAIN

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    Hadiwiyono, S. Subandiyah, C. Sumardiyono, J. Widada, and M. Fegan.

    2012-02-01

    Full Text Available Effect of Altitude and Wounding on Blood Disease Progress of Plantain. In the latest decade, the blood disease of banana has spread in almost all provinces in Indonesia and caused wilting of millions banana clusters in several provinces.  It is very difficult to control the disease due  to the base data about ecology and epidemiology of the pathogen are still poorly understood. This research aimed to evaluate the effect of  wounding of inoculation site on blood disease progress of plantain. The experiment was arranged using randomized completely block design It was conducted at three locations with altitude of 100, 1000, and 1600 m above sea levels as replication block. The treatments were wounding, unwounding inoculation site, inoculation, and uninoculation of plantain cv. Kepok Kuning Wounding was applied by stabbing with an injection pin around the corm of 15 stabs/seedling. The seedlings were planted singly in one liter of non sterile soil in plastic bag.  Each treatment consisted of 5 seedlings which was replicated 3 times. Inoculation was done  by soil drenching of 20 ml bacterial suspension at  concentration of 108 cfu/ml two week after planting.  The pathogen used for inoculation originated from low land area (about 100 m above sea level.  Observation was done weekly for 5 weeks. The variables observed were wilt intensity and area under disease progress (AUDPC. The results showed that blood disease was able to establish at altitude of 1600 m above sea level. The disease progress however was slower that those at 100 and 1000 m above sea level. On wounded seedling, the disease progress was more aggressive than those on unwounded one.

  11. Companion cropping with potato onion enhances the disease resistance of tomato against Verticillium dahliae

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    Xuepeng eFu

    2015-09-01

    Full Text Available Intercropping could alleviate soil-borne diseases, however, few studies focused on the immunity of the host plant induced by the interspecific interactions. To test whether or not intercropping could enhance the disease resistance of host plant, we investigated the effect of companion cropping with potato onion on tomato Verticillium wilt caused by Verticillium dahliae (V. dahliae. To investigate the mechanisms, the root exudates were collected from tomato and potato onion which were grown together or separately, and were used to examine the antifungal activities against V. dahliae in vitro, respectively. Furthermore, RNA-seq was used to examine the expression pattern of genes related to disease resistance in tomato companied with potato onion compared to that in tomato grown alone, under the condition of infection with V. dahliae. The results showed that companion cropping with potato onion could alleviate the incidence and severity of tomato Verticillium wilt. The further studies revealed that the root exudates from tomato companied with potato onion significantly inhibited the mycelia growth and spore germination of V. dahliae. However, there were no significant effects on these two measurements for the root exudates from potato onion grown alone or from potato onion grown with tomato. RNA-seq data analysis showed the disease defense genes associated with pathogenesis-related proteins, biosynthesis of lignin, hormone metabolism and signal transduction were expressed much higher in the tomato companied with potato onion than those in the tomato grown alone, which indicated that these defense genes play important roles in tomato against V. dahliae infection, and meant that the disease resistance of tomato against V. dahliae was enhanced in the companion copping with potato onion. We proposed that companion cropping with potato onion could enhance the disease resistance of tomato against V. dahliae by regulating the expression of genes related

  12. 'Candidatus Phytoplasma palmicola', associated with a lethal yellowing-type disease of coconut (Cocos nucifera L.) in Mozambique.

    Science.gov (United States)

    Harrison, Nigel A; Davis, Robert E; Oropeza, Carlos; Helmick, Ericka E; Narváez, María; Eden-Green, Simon; Dollet, Michel; Dickinson, Matthew

    2014-06-01

    In this study, the taxonomic position and group classification of the phytoplasma associated with a lethal yellowing-type disease (LYD) of coconut (Cocos nucifera L.) in Mozambique were addressed. Pairwise similarity values based on alignment of nearly full-length 16S rRNA gene sequences (1530 bp) revealed that the Mozambique coconut phytoplasma (LYDM) shared 100% identity with a comparable sequence derived from a phytoplasma strain (LDN) responsible for Awka wilt disease of coconut in Nigeria, and shared 99.0-99.6% identity with 16S rRNA gene sequences from strains associated with Cape St Paul wilt (CSPW) disease of coconut in Ghana and Côte d'Ivoire. Similarity scores further determined that the 16S rRNA gene of the LYDM phytoplasma shared coconut LYDM phytoplasma strains from Mozambique as novel members of established group 16SrXXII, subgroup A (16SrXXII-A). Similarity coefficients of 0.97 were obtained for comparisons between subgroup 16SrXXII-A strains and CSPW phytoplasmas from Ghana and Côte d'Ivoire. On this basis, the CSPW phytoplasma strains were designated members of a novel subgroup, 16SrXXII-B.

  13. Control of wilt and rot pathogens of tomato by antagonistic pink pigmented facultative methylotrophic Delftia lacustris and Bacillus spp.

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    Veeranan Janahiraman

    2016-11-01

    Full Text Available The studies on the biocontrol potential of pink pigmented facultative methylotrophic (PPFM bacteria other than the genus Methylobacterium are scarce. In the present study, we report three facultative methylotrophic isolates; PPO-1, PPT-1 and PPB-1, respectively identified as Delftia lacustris, Bacillus subtilis and Bacillus cereus by 16S rRNA gene sequence analysis. Hemolytic activity was tested to investigate the potential pathogenicity of isolates to plants and humans, the results indicates that the isolates PPO-1, PPT-1 and PPB-1 are not pathogenic strains. Under in vitro conditions, D. lacustris PPO-1, B. subtilis PPT-1 and B. cereus PPB-1 showed direct antagonistic effect by inhibiting the mycelial growth of fungal pathogens; Fusarium oxysporum f. sp. lycopersici (2.15, 2.05 and 1.95 cm, Sclerotium rolfsii (2.14, 2.04 and1.94 cm, Pythium ultimum (2.12, 2.02 and 1.92cm, and Rhizoctonia solani (2.18, 2.08 and 1.98 cm and also produced volatile inhibitory compounds. Under plant growth chamber condition methylotrophic bacterial isolates; D. lacustris PPO-1, B. subtilis PPT-1 and B. cereus PPB-1 significantly reduced the disease incidence of tomato. Under greenhouse condition, D. lacustris PPO-1, B. subtilis PPT-1 and B. cereus PPB-1 inoculated tomato plants, when challenged with F. oxysporum f. sp. lycopersici, S. rolfsii, P. ultimum and R. solani, increased the pathogenesis related proteins (β-1, 3-glucanase and chitinase and defense enzymes (phenylalanine ammonia lyase, peroxidase, polyphenol oxidase, and catalase on day 5 after inoculation. In the current study, we first report the facultative methylotrophy in pink pigmented Delftia lacustris, B. subtilis, and B. cereus and their antagonistic potential against fungal pathogens. Direct antagonistic and ISR effects of these isolates against fungal pathogens of tomato evidenced their possible use as a biocontrol agent.

  14. Exigências térmicas e estimativas do número de gerações de ortézia dos citros criadas em limão-cravo Temperature requirements and generation number estimates of croton mealybug reared in Rangpur lime

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    Ademir Diniz Neves

    2010-08-01

    Full Text Available O objetivo deste trabalho foi determinar as exigências térmicas para o desenvolvimento de ortézia dos citros (Praelongorthezia praelonga e estimar o número de gerações por ano nos municipios de Bauru, Barretos, São José do Rio Preto, Bebedouro, Avaré, Araraquara, Itapetininga e Limeira, no Estado de São Paulo. Para a determinação da duração das fases de ovo e ninfa, e de suas exigências térmicas, criaram-se insetos em mudas de limão-cravo (Citrus limonia a 18, 20, 22, 25, 28, 30 e 32ºC, umidade relativa de 70±10% e fotofase de 14 horas. A duração das fases de desenvolvimento e do ciclo biológico (ovo-adulto foi afetada pela temperatura, tendo sido maior nas temperaturas mais baixas. O limiar térmico inferior de desenvolvimento (Tb e a constante térmica (K para as fases ovo, ninfa e período ovo-adulto foram 6,16ºC e 398,40 graus-dia (GD, 12,10ºC e 374,50 GD, e 10,28ºC e 735,29 GD, respectivamente. Com base nas médias de temperatura do ar dos diferentes municípios avaliados, o número de gerações por ano varia de 4,99 a 6,60.The objective of this work was to determine the temperature requirements for the development of croton mealybug (Praelongorthezia praelonga and to estimate the number of year generations at the state of São Paulo, Brazil, counties of Bauru, Barretos, São José do Rio Preto, Bebedouro, Avaré, Araraquara, Itapetininga and Limeira. In order to determine stage durations of egg and nymph stages, and their temperature requirements, the insects were reared on Rangpur lime (Citrus limonia seedlings at 18, 20, 22, 25, 28, 30 e 32ºC, under 70±10% relative humidity and a 14-hour photofase. Developmental stages and biological cycle (egg-adult durations were affected by temperature, and higher values of these parameters were obtained at lower temperatures. The lowest temperature development threshold (TT and thermal constant (K for egg and nymph stages and for the egg-adult period were 6.16ºC and 398

  15. Cacao diseases: important threats to chocolate production worldwide.

    Science.gov (United States)

    Ploetz, Randy C

    2007-12-01

    ABSTRACT Theobroma cacao, cacao, is an ancient, neotropical domesticate. It is now grown throughout the humid, lowland tropics and is the basis of a multibillion dollar confectionary trade. Diverse diseases impact production of the crop. They reduce yields by ca. 20%, but could cause far greater losses if certain highly damaging diseases were to become more widely distributed. Among the most potentially dangerous of these diseases are frosty pod, caused by Moniliophthora roreri, and witches' broom, caused by M. perniciosa (previously Crinipellis perniciosa). These two diseases occur only in the Western Hemisphere, and severe losses would follow their introduction to West Africa and Asia, where ca. 86% of all cacao production occurs. Elsewhere, Cacao swollen shoot virus and the damaging black pod agent, Phytophthora megakarya, are found in Western Africa; whereas vascular streak dieback, caused by Oncobasidium theobromae, is present only in Asia. Breeding programs are challenged by minimal resistance to some of the diseases. Progress that has been made is threatened by the "emergence" of other serious diseases, such as Ceratocystis wilt (Ceratocystis cacaofunesta). During this symposium, new insights are discussed on the biology, origins, pathology and phylogeny of the pathogens; as well as the biological, chemical and genetic management of the diseases that they cause.

  16. Proteome Analysis of Disease Resistance against Ralstonia solanacearum in Potato Cultivar CT206-10

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    Sangryeol Park

    2016-02-01

    Full Text Available Potato is one of the most important crops worldwide. Its commercial cultivars are highly susceptible to many fungal and bacterial diseases. Among these, bacterial wilt caused by Ralstonia solanacearum causes significant yield loss. In the present study, integrated proteomics and genomics approaches were used in order to identify bacterial wilt resistant genes from Rs resistance potato cultivar CT-206-10. 2-DE and MALDI-TOF/TOF-MS analysis identified eight differentially abundant proteins including glycine-rich RNA binding protein (GRP, tomato stress induced-1 (TSI-1 protein, pathogenesis-related (STH-2 protein and pentatricopeptide repeat containing (PPR protein in response to Rs infection. Further, semi-quantitative RT-PCR identified up-regulation in transcript levels of all these genes upon Rs infection. Taken together, our results showed the involvement of the identified proteins in the Rs stress tolerance in potato. In the future, it would be interesting to raise the transgenic plants to further validate their involvement in resistance against Rs in potato.

  17. An Unwelcome Guest in China: A Pine-Feeding Mealybug

    Science.gov (United States)

    Jianghua Sun; Gary L. DeBarr; Tong-Xian Liu; C. Wayne Berisford; Stephen R. Clarke

    1996-01-01

    This story began in January 1988. Two business representatives from the Seed Company of the Ministry of the Forestry, People's Republic of China, visited the Southern Seed Company in Baldwin, Georgia, during a seed-buying trip. Just before leaving, they collected 70 scions from slash pines (Pinus elliotti) in a second-generation seed orchard...

  18. Valor nutritivo de silagens de capim-elefante emurchecido ou com adição de farelo de cacau Nutritive value of elephantgrass silage wilted or with addition of cocoa meal

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    Gleidson Giordano Pinto de Carvalho

    2007-10-01

    Full Text Available O experimento foi conduzido para avaliar o valor nutritivo da silagem de capim-elefante produzida com o capim emurchecido ou adicionada de diferentes níveis de farelo de cacau. O capim-elefante foi colhido aos 50 dias de rebrota após o corte de uniformização e submetido aos seguintes tratamentos na ensilagem: capim-elefante emurchecido ao sol por 8 horas, e capim-elefante sem emurchecimento com 0, 7, 14, 21 e 28% de farelo de cacau (FC (% da matéria natural. Foram utilizadas quatro repetições por tratamento; o material foi acondicionado em silos de PVC com 0,15 m de diâmetro e 0,3 m de altura, adotando-se compactação de 500 kg/m³. A inclusão do farelo de cacau na ensilagem do capim-elefante mostrou-se eficiente em aumentar o teor de MS da silagem. A inclusão de FC no nível de 7% permitiu produção de silagem com teor de MS semelhante ao da silagem de capim emurchecido. As silagens com FC apresentaram maiores teores de NT, EE, lignina, NIDN e NIDA, no entanto, os teores de FDN, FDA CEL, HEM, cinzas e NDT e a DIVMS diminuíram com a adição de farelo de cacau. O NDT estimado para a silagem de capim emurchecido foi superior ao obtido nas demais silagens, com e sem farelo de cacau. Embora o FC tenha promovido redução da DIVMS, sua inclusão nos níveis de 7 e 14% proporcionou boa digestibilidade das silagens (acima de 60%. O emurchecimento do capim-elefante e a adição de FC podem ser alternativas para aumentar o teor de MS da silagem e garantir a produção de silagens de bom valor nutritivo.The experiment was carried out to evaluate the nutritive value of elephant grass silage wilted under the sun light for eight hours. Other treatments involved the same elephant grass without exposing to sun light but with addition of 0, 7, 14, 21, and 28% of cocoa meal (CM at the ensilage process. The PVC silos used in the experiment measured 0.15 m of diameter and 0.30 m of height. During the ensiling process the forage was compressed until

  19. Murcha do manjericão (Ocimum basilicum no Brasil: agente causal, círculo de plantas hospedeiras e transmissão via semente Sweet basil (Ocimum basilicum wilt in Brazil: causal agent, host range and seed transmission

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    Ailton Reis

    2007-06-01

    representam o mais provável veículo de introdução e potencial disseminação deste patógeno no Brasil.Sweet basil (Ocimum basilicum L is one of the most important vegetable crops in the family Lamiaceae, being employed mainly as a source of essential oils for the pharmaceutical industry. Samples of plants showing symptoms of wilt, stem blight and collar root rot were collected during the 2005 hot rainy season in the rural area of Brazlândia (Federal District in central Brazil. Two other samples displaying identical symptoms were collected under greenhouse and field conditions in Ponte Alta (DF. The fungus Fusarium oxysporum was consistently isolated in all samples. Pathogenicity tests were conducted using seedlings and stem cuttings of the O. basilicum cultivars 'Dark Opal' and 'Italian Large Leaf' as well as accessions of the species O. americanum L, O. campechianum Mill., Origanum manjorana L., O. vulgare L., Mentha arvensis L., Coleus blumei Benth., Leonorus sibiricus L. and Leonotis nepetaefolia (L. W.T. Aiton. All isolates were highly virulent on O. basilicum cultivars, whereas O. campechianum and O. americanum cultivars reacted with a slight vascular browning and with a very mild reduction in plant growth rate. All isolates were considered avirulent to O. manjorana, O. vulgaris, M. arvensis, C. blumei, L. sibiricus and L. nepetaefolia accessions. The experimental data indicated that the causal agent of this disease is the fungus F. oxysporum f. sp. basilici. This is the first formal report of this pathogen in Brazil. The remaining seeds from commercial lots that were sowed in the areas where the pathogen was first described were evaluated for the presence of F. oxysporum f. sp. basilici. This fungus was detected in four out of six seed lots and the seed-derived isolates were able to induce similar set of symptoms in the same group of plant accessions. This result strongly suggests that this new disease in Brazil was most likely introduced into the country via

  20. Qualidade e valor nutritivo de silagens de capim-marandu (B. brizantha cv. Marandu produzidas com aditivos ou forragem emurchecida Quality and nutritive value of marandugrass (Brachiaria brizanthia, cv. Marandu silage prepared with additive or wilting

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    Antonio Fernando Bergamaschine

    2006-08-01

    Full Text Available Avaliaram-se a qualidade e o valor nutritivo de silagens de capim-marandu produzidas com polpa cítrica (PC peletizada, com aditivo enzimático-bacteriano (ABE ou com forragem emuchercida (E: T1 - forragem sem tratamento (controle; T2 - 10% de polpa cítrica peletizada (PC; T3 - aditivo enzimático bacteriano (AEB - SIL-ALL-C4 da Alltech, à base de 5 g/L de água/t de forragem; T4 - forragem picada grosseiramente emurchecida por 4 horas ao sol. O capim foi colhido aos 60 dias de rebrota (24% MS. Para avaliar o consumo e a digestibilidade das silagens, foram utilizados 16 novilhos mestiços com 200 kg de PV, que receberam, além das silagens, 1,0 kg de concentrado/animal/dia. O AEB não afetou a composição da silagem, mas a PC e o E aumentaram o teor de MS de 24% para 31 e 48%, respectivamente, e reduziram o pH e os teores de N-NH3 das silagens, que foram, respectivamente, de 4,17 e 4,58 e 6,78 e 7,99% NT. A PC diminuiu os teores de FDN e FDA em 12 e 4 unidades percentuais. O consumo de MS da silagem produzida com capim emurchecido foi superior (111,8 g MS/PV0,75 ao das silagens controle ou com AEB, mas não diferiu do obtido para a silagem com PC, que também não diferiu das demais. Os tratamentos não afetaram a digestibilidade, cujas médias para MS, PB, CT, FDN, FDA e NDT foram 67,0; 65,4; 68,8; 63,0; 62,5; e 65,6%, respectivamente. A PC e o E reduziram a proteólise e estimularam o consumo. A PC, o E e o AEB não melhoraram o valor nutritivo da silagem de capim-marandu colhido com 24% MS.The objective of this experiment was to evaluate the quality and nutritive value of marandugrass silages. It was evaluated the followings treatments: T1- forage without treatment (control; T2 - 10% of pelleted citric pulp (CiP; T3 - enzymatic bacterial additive (EBA (SIL-ALL-C4 of Alltech applied at 5 g/L of water/t of forage; T4 - Coarse chopped forage wilted for 4 hours under the sun. The grass was harvested with 60 days of regrowth (24% DM. The intake