Hansen, A.K.; Trumble, J T; Stouthamer, R; Paine, T. D.
A new huanglongbing (HLB) “Candidatus Liberibacter” species is genetically characterized, and the bacterium is designated “Candidatus Liberibacter psyllaurous.” This bacterium infects the psyllid Bactericera cockerelli and its solanaceous host plants potato and tomato, potentially resulting in “psyllid yellowing.” Host plant-dependent HLB transmission and variation in psyllid infection frequencies are found.
The potato psyllid (Bactericera cockerelli Sulc) is an economically important insect pest of solanaceous crops such as potato, tomato, pepper, and tobacco. Historically, the potato psyllid’s range included central United States, Mexico, and California; more recently, populations of this insect have ...
Luna Cruz, Alfonso
Bactericera cockerelli es una de las plagas más importantes en solanáceas en México. Su manejo se basa en el uso de insecticidas y recientemente se ha explorado el uso del parasitoide Tamarixia triozae dentro de un programa de MIP. El objetivo del presente trabajo fue explorar la compatibilidad de insecticidas con este parasitoide. En este trabajo se evaluó, en condiciones de laboratorio (25±2ºC, 60±5% H.R.), la toxicidad de Azadiractina, Spinosad, Imidacloprid y Abamectina sobre T. triozae y...
The potato psyllid, Bactericera cockerelli Sulc, has recently been identified as a vector of Candidatus Liberibacter, the putative causal agent of zebra chip (ZC) potato disease. ZC is causing millions of dollars in losses to the potato industry in the United States, Mexico, Central America, and New...
The potato psyllid, Bactericera (= Paratrioza) cockerelli (Šulc) (Hemiptera: Triozidae), is a major pest of potato. We examined the role of chemical signals in sex attraction, assessing male and female response to male- and female-produced volatile chemicals. In laboratory olfactometer assays, pot...
Relación entre Bactericera cockerelli y presencia de Candidatus Liberibacter psyllaurous en lotes comerciales de papa Relation between Bactericera cockerelli and presence of Candidatus Liberibacter psyllaurous in commercial fields of potato
Oswaldo Ángel Rubio-Covarrubias; Isidro Humberto Almeyda-León; Mateo Armando Cadena-Hinojosa; René Lobato-Sánchez
La brotación anormal de los tubérculos (sin brotes o brotes ahilados) y el pardeamiento interno de los tubérculos, son síntomas de una enfermedad que está afectando la producción de papa en México, en el suroeste de Estados Unidos y América central. Esta enfermedad ha sido asociada con el psilido de la papa Bactericera cockerelli Sulc. Con el objetivo de dilucidar las causas de esta enfermedad, en 2007 se llevó a cabo un muestreo en 11 lotes comerciales de papa localizados en un transecto alt...
Ibanez, Freddy; Hancock, Joseph; Tamborindeguy, Cecilia
Aquaporin (AQPs) proteins transport water and uncharged low molecular-weight solutes across biological membranes. Six to 8 AQP genes have been identified in many insect species, but presently only three aquaporins have been characterized in phloem feeding insects. The objective of this study was to identify candidate AQPs in the potato psyllid, Bactericera cockerelli. Herein, we identified four candidate aquaporin cDNAs in B. cockerelli transcriptome. Phylogenetic analysis showed that candida...
Relación entre Bactericera cockerelli y presencia de Candidatus Liberibacter psyllaurous en lotes comerciales de papa Relation between Bactericera cockerelli and presence of Candidatus Liberibacter psyllaurous in commercial fields of potato
Oswaldo Ángel Rubio-Covarrubias
Full Text Available La brotación anormal de los tubérculos (sin brotes o brotes ahilados y el pardeamiento interno de los tubérculos, son síntomas de una enfermedad que está afectando la producción de papa en México, en el suroeste de Estados Unidos y América central. Esta enfermedad ha sido asociada con el psilido de la papa Bactericera cockerelli Sulc. Con el objetivo de dilucidar las causas de esta enfermedad, en 2007 se llevó a cabo un muestreo en 11 lotes comerciales de papa localizados en un transecto altitudinal entre 2 600 y 3 500 m en la región productora de papa de Toluca. La población de B. cockerelli fue determinada mediante muestreos semanales de los insectos adultos atrapados en trampas amarillas pegajosas. Al final del periodo de crecimiento del cultivo, los tubérculos producidos en cada lote fueron muestreados y almacenados por 6 meses. Después de este tiempo, se determinó el porcentaje de tubérculos con brotación anormal y se hicieron análisis con PCR para determinar la presencia de Candidatus Liberibacter psyllaurous y de fitoplasmas en los tubérculos. Los resultados indican que la población de B. cockerelli y de los síntomas de la punta morada de la papa disminuyeron con la altura, en alturas superiores a 3 200 msnm no se presentaron problemas significativas de la enfermedad. El 36% de los tubérculos con brotes finos presentó el pardeamiento interno y 58% de los tubérculos sin brotes presentó el mismo síntoma. El 54% de los tubérculos con brotación anormal fue positivo a Candidatus Liberibacter psyllaurous y sólo 3.5% a fitoplasmas. Estos resultados indican que Candidatus Liberibacter psyllaurous está asociada con los síntomas de la punta morada de la papa en la región de Toluca.The abnormal sprouting of tubers (without sprouts or with threadlike sprouts and the internal browning of the potatoes are symptoms of a disease which is affecting the potato production in Mexico, in southwestern United States and Central
We investigated the effect of mating on female attractiveness and male responsiveness in the potato psyllid, Bactericera (= Paratrioza) cockerelli (Šulc) (Hemiptera: Triozidae), a major pest of potato. Mating induced a behavioral refractoriness during which males are not attracted to females. This ...
Potato psyllid, Bactericera cockerelli (Šulc) (Hemiptera: Triozidae) is a key pest of potato and the vector of "Candidatus Liberibacter solanacearum," the pathogen associated with zebra chip disease. Development of potato cultivars with genetic resistance to potato psyllid would enable cost-effecti...
Bactericera cockerelli has recently become a major concern because of its direct feeding and vectoring of bacterial diseases in many solanaceous crops. The repellency of four biorational insecticides, MOI-201 (a Chinese medicine plant extract), Requiem (a plant extract of Chenopodium ambrosioides), ...
Luna-Cruz, Alfonso; Rodríguez-Leyva, Esteban; Lomeli-Flores, J Refugio; Ortega-Arenas, Laura D; Bautista-Martínez, Néstor; Pineda, Samuel
Bactericera cockerelli (Sulc) (Hemiptera: Triozidae) is one of the most economically important pests of potato, tomato, and peppers in Central America, Mexico, the United States, and New Zealand. Its control is based on the use of insecticides; however, recently, the potential of the eulophid parasitoid Tamarixia triozae (Burks) (Hymenoptera: Eulophidae) for population regulation has been studied. Because T. triozae is likely to be exposed to insecticides on crops, the objective of this study was to explore the compatibility of eight insecticides with this parasitoid. The toxicity and residual activity (persistence) of spirotetramat, spiromesifen, beta-cyfluthrin, pymetrozine, azadirachtin, imidacloprid, abamectin, and spinosad against T. triozae adults were assessed using a method based on the residual contact activity of each insecticide on tomato leaf discs collected from treated plants growing under greenhouse conditions. All eight insecticides were toxic to T. triozae. Following the classification of the International Organization of Biological Control, the most toxic were abamectin and spinosad, which could be placed in toxicity categories 3 and 4, respectively. The least toxic were azadirachtin, pymetrozine, spirotetramat, spiromesifen, imidacloprid, and beta-cyfluthrin, which could be placed in toxicity category 2. In terms of persistence, by day 5, 6, 9, 11, 13, 24, and 41 after application, spirotetramat, azadirachtin, spiromesifen, pymetrozine, imidacloprid, beta-cyfluthrin, abamectin, and spinosad could be considered harmless, that is, placed in toxicity category 1 (pest management programs that include T. triozae. PMID:26453717
Christelle Guédot; David R.Horton; Peter J.Landolt
The potato psyllid,Bactericera (=Paratrioza) cockerelli ((S)ulc) (Hemiptera:Triozidae),is a major pest of potato.Studies were conducted to determine the age at which both males and females reach reproductive maturity and the effect of age and time of day on sex attraction.Adult B.cockerelli reach reproductive maturity within 48 h post-eclosion,with females being mature on the day of eclosion and males at 1 day post-eclosion.Oviposition generally began 2 days after mating but was delayed when females mated within 2 days post-eclosion.In laboratory olfactometer assays,the age of females used as odor sources and the age of males assayed to these odors did not affect sex attraction,with both younger (1-4-day-old) and older (8-10-day-old) males being attracted to females,regardless of female age (1-4-day-old or 8-10-day-old).Males assayed to live females at different times during the photophase (between 8:00 and 20:00 hours) were attracted to females between 11:00 and 17:00 hours,showing a temporal periodicity in sex attraction with B.cockerelli at least during the photophase.
Liu, Tong-Xian; Zhang, Yong-Mei; Peng, Li-Nian; Rojas, Patricia; Trumble, John T
Tamarixia triozae (Burks) (Hymenoptera: Eulophidae) is an important parasitoid of the potato or tomato psyllid, Bactericera cockerelli (Sulc) (Hemiptera: Trizoidae), a serious pest of potato (Solanum tuberosum L.), tomato (Solanum lycopersicum L.), and other solanaceous vegetables in many countries. To produce a marketable crop, insecticides are required when B. cockerelli populations reach economically damaging levels. We evaluated 11 commonly used insecticides for their effects on T. triozae. Glass-surface residues of spinetoram, imidacloprid-cyfluthrin, abamectin, and tolfenpyrad caused 100% mortality of T. triozae in 72 h, and the leaf residue of spinetoram was extremely toxic to T. triozae adults; even 15-d-old residues caused 100% mortality. Cyantraniliprole, fenpyroximate, pymetrozine, spirotetramat, spiromesifen, and chenopodium oil did not cause significant mortality in either glass surface or leaf-residue bioassays. Ingestion of spinetoram, abamectin, and imidacloprid+cyfluthrin (Leverage) by the adults resulted in 100% mortality in 12 h, and tolfenpyrad, 75.0% mortality in 12 h; whereas chenopodium oil and pymetrozine showed moderate effects on adult survival. Ingestion of abamectin, imidacloprid-cyfluthrin, and spinetoram killed all adults in the first day of treatment, whereas female adults in the treatment of pymetrozine lived 80.8 d, which was similar to those in the control. Ingestion of abamectin, imidacloprid-cyfluthrin, chenopodium oil, and spinetoram killed all male adults in the first day, whereas ingestion of other insecticides did not cause significant mortality, but reduced percent parasitism. Abamectin, imidacloprid-cyfluthrin, and spinetoram had the most deleterious effects on T. triozae, and have the least potential for use in integrated control programs using this parasitoid. PMID:22606819
Ibanez, Freddy; Levy, Julien; Tamborindeguy, Cecilia
“Candidatus Liberibacter solanacearum” (Lso) is an emergent pathogen of carrots in Europe and solanaceous plants in North and Central America and New Zealand. This bacterium is closely related to other pathogenic Candidatus Liberibacter spp., all vectored by psyllids. In order to understand the molecular interaction of this pathogen and its psyllid vector, Bactericera cockerelli, Illumina sequencing of psyllid harboring Lso was performed to determine if this approach could be used to assess t...
Sean M. Prager; Esquivel, Isaac; Trumble, John T.
Among the many topics of interest to ecologists studying associations between phytophagous insects and their host plants are the influence of natal host plant on future oviposition decisions and the mechanisms of generalist versus specialist host selection behavior. In this study, we examined the oviposition preferences, behavior and larval development of the tomato/potato psyllid, Bactericera cockerelli. By rearing psyllids with two distinct geographically-linked haplotypes on different host...
Full Text Available Potato psyllid (Bactericera cockerelli is an important pest of potato, tomato and pepper. Not only could a toxin secreted by nymphs results in serious phytotoxemia in some host plants, but also over the past few years B. cockerelli was shown to transmit "Candidatus Liberibacter solanacearum", the putative bacterial pathogen of potato zebra chip (ZC disease, to potato and tomato. ZC has caused devastating losses to potato production in the western U.S., Mexico, and elsewhere. New knowledge of the genetic diversity of the B. cockerelli is needed to develop improved strategies to manage pest populations. Mitochondrial genome (mitogenome sequencing provides important knowledge about insect evolution and diversity in and among populations. This report provides the first complete B. cockerelli mitogenome sequence as determined by next generation sequencing technology (Illumina MiSeq. The circular B. cockerelli mitogenome had a size of 15,220 bp with 13 protein-coding gene (PCGs, 2 ribosomal RNA genes (rRNAs, 22 transfer RNA genes (tRNAs, and a non-coding region of 975 bp. The overall gene order of the B. cockerelli mitogenome is identical to three other published Psylloidea mitogenomes: one species from the Triozidae, Paratrioza sinica; and two species from the Psyllidae, Cacopsylla coccinea and Pachypsylla venusta. This suggests all of these species share a common ancestral mitogenome. However, sequence analyses revealed differences between and among the insect families, in particular a unique region that can be folded into three stem-loop secondary structures present only within the B. cockerelli mitogenome. A phylogenetic tree based on the 13 PCGs matched an existing taxonomy scheme that was based on morphological characteristics. The available complete mitogenome sequence makes it accessible to all genes for future population diversity evaluation of B. cockerelli.
Wu, Fengnian; Cen, Yijing; Wallis, Christopher M.; Trumble, John T.; Prager, Sean; Yokomi, Ray; Zheng, Zheng; Deng, Xiaoling; Chen, Jianchi; Liang, Guangwen
Potato psyllid (Bactericera cockerelli) is an important pest of potato, tomato and pepper. Not only could a toxin secreted by nymphs results in serious phytotoxemia in some host plants, but also over the past few years B. cockerelli was shown to transmit “Candidatus Liberibacter solanacearum”, the putative bacterial pathogen of potato zebra chip (ZC) disease, to potato and tomato. ZC has caused devastating losses to potato production in the western U.S., Mexico, and elsewhere. New knowledge of the genetic diversity of the B. cockerelli is needed to develop improved strategies to manage pest populations. Mitochondrial genome (mitogenome) sequencing provides important knowledge about insect evolution and diversity in and among populations. This report provides the first complete B. cockerelli mitogenome sequence as determined by next generation sequencing technology (Illumina MiSeq). The circular B. cockerelli mitogenome had a size of 15,220 bp with 13 protein-coding gene (PCGs), 2 ribosomal RNA genes (rRNAs), 22 transfer RNA genes (tRNAs), and a non-coding region of 975 bp. The overall gene order of the B. cockerelli mitogenome is identical to three other published Psylloidea mitogenomes: one species from the Triozidae, Paratrioza sinica; and two species from the Psyllidae, Cacopsylla coccinea and Pachypsylla venusta. This suggests all of these species share a common ancestral mitogenome. However, sequence analyses revealed differences between and among the insect families, in particular a unique region that can be folded into three stem-loop secondary structures present only within the B. cockerelli mitogenome. A phylogenetic tree based on the 13 PCGs matched an existing taxonomy scheme that was based on morphological characteristics. The available complete mitogenome sequence makes it accessible to all genes for future population diversity evaluation of B. cockerelli. PMID:27227976
Potato psyllid, Bactericera cockerelli (Šulc), is a serious pest of potato, tomato and other solanaceous vegetables in the United States, Mexico, Central America, and New Zealand and is responsible for transmission of Candidatus Liberibacter solanacearum causing a disease known as “zebra chip” (ZC)....
Munyaneza, J E; Crosslin, J M; Upton, J E
A new defect of potato, Solanum tuberosum L., "zebra chip," so named for the characteristic symptoms that develop in fried chips from infected potato tubers, has recently been documented in several southwestern states of the United States, in Mexico, and in Central America. This defect is causing millions of dollars in losses to both potato producers and processors. Zebra chip plant symptoms resemble those caused by potato purple top and psyllid yellows diseases. Experiments were conducted to elucidate the association between the psyllid Bactericera cockerelli (Sulc) (Homoptera: Psyllidae) and zebra chip by exposing clean potato plants to this insect under greenhouse and field conditions. Potato plants and tubers exhibiting zebra chip symptoms were tested for phytoplasmas by polymerase chain reaction. Potato psyllids collected from infected potato fields also were tested. Results indicated that there was an association between the potato psyllid and zebra chip. Plants exposed to psyllids in the greenhouse and field developed zebra chip. In the greenhouse, 25.8 and 59.2% of tubers exhibited zebra chip symptoms in the raw tubers and fried chips, respectively. In the field, 15 and 57% of tubers showed symptoms in raw tubers and chips, respectively. No zebra chip was observed in tubers from plants that had not been exposed to psyllids, either in the greenhouse or field. No phytoplasmas were detected from potato plants or tubers with zebra chip symptoms, suggesting that these pathogens are not involved in zebra chip. Of the 47 samples of potato psyllids tested, only two tested positive for the Columbia Basin potato purple top phytoplasma. PMID:17598522
Cooper, W Rodney; Horton, David R; Unruh, Thomas R; Garczynski, Stephen F
Potato psyllid, Bactericera cockerelli (Šulc) (Hemiptera: Triozidae), is a key pest of potato (Solanum tuberosum L., Solanales: Solanaceae) and a vector of "Candidatus Liberibacter solanacearum," the pathogen associated with zebra chip disease. In addition to its presence on cultivated crops, the psyllid regularly occurs on numerous uncultivated annual and perennial species within the Solanaceae. A better understanding of landscape-level ecology of B. cockerelli would substantially improve our ability to predict which potato fields are most likely to be colonized by infected psyllids. We developed three PCR-based methods of gut content analysis to identify what plant species B. cockerelli had previously fed upon. These methods included-1) sequencing PCR amplicons of regions of plant-derived internal transcribed spacer (ITS) or the chloroplast trnL gene from psyllids, 2) high-resolution melting analysis of ITS or trnL real-time PCR products, and 3) restriction enzyme digestion of trnL PCR product. Each method was used to test whether we could identify psyllids that had been reared continuously on potato versus psyllids reared continuously on the perennial nightshade, Solanum dulcamara. All three methods of gut content analysis correctly identified psyllids from potato and psyllids from S. dulcamara Our study is the first to demonstrate that plant DNA can be detected in a phloem-feeding insect. Gut content analysis, in combination with other landscape ecology approaches, could help elucidate patterns in landscape-level movements and host plant associations of B. cockerelli. PMID:27271944
Full Text Available The potato/tomato psyllid, Bactericera cockerelli (B. cockerelli, is an important plant pest and the vector of the phloem-limited bacterium Candidatus Liberibacter psyllaurous (solanacearum, which is associated with the zebra chip disease of potatoes. Previously, we reported induction of RNA interference effects in B. cockerelli via in vitro-prepared dsRNA/siRNAs after intrathoracic injection, and after feeding of artificial diets containing these effector RNAs. In order to deliver RNAi effectors via plant hosts and to rapidly identify effective target sequences in plant-feeding B. cockerelli, here we developed a plant virus vector-based in planta system for evaluating candidate sequences. We show that recombinant Tobacco mosaic virus (TMV containing B. cockerelli sequences can efficiently infect and generate small interfering RNAs in tomato (Solanum lycopersicum, tomatillo (Physalis philadelphica and tobacco (Nicotiana tabacum plants, and more importantly delivery of interfering sequences via TMV induces RNAi effects, as measured by actin and V-ATPase mRNA reductions, in B. cockerelli feeding on these plants. RNAi effects were primarily detected in the B. cockerelli guts. In contrast to our results with TMV, recombinant Potato virus X (PVX and Tobacco rattle virus (TRV did not give robust infections in all plants and did not induce detectable RNAi effects in B. cockerelli. The greatest RNA interference effects were observed when B. cockerelli nymphs were allowed to feed on leaf discs collected from inoculated or lower expanded leaves from corresponding TMV-infected plants. Tomatillo plants infected with recombinant TMV containing B. cockerelli actin or V-ATPase sequences also showed phenotypic effects resulting in decreased B. cockerelli progeny production as compared to plants infected by recombinant TMV containing GFP. These results showed that RNAi effects can be achieved in plants against the phloem feeder, B. cockerelli, and the TMV
Ibanez, F; Tamborindeguy, C
The selection of reference genes is a crucial step for quantitative real-time PCR analyses and increasingly the use of more than one reference gene for accurate and reliable normalization is being recommended. In this study, a set of six genes was selected and their stability was assessed in different life stages and female organs of Bactericera cockerelli harbouring or not the bacterial pathogen 'Candidatus Liberibacter solanacearum' (Lso) haplotype B. The stability of each gene was determined using the BestKeeper, NormFinder and GeNorm programs. These analyses identified elongation factor-1a, ribosomal protein subunit L5 and ribosomal protein subunit 18 as the most stable genes to analyse gene expression during the insect life stages irrespective of Lso presence; Lso haplotype B only affected their respective ranking. By contrast, a common set of normalizers could not be found amongst the different female organs tested (bacteriomes, alimentary canals and reproductive organs). PMID:26936438
Full Text Available Aquaporin (AQPs proteins transport water and uncharged low molecular-weight solutes across biological membranes. Six to 8 AQP genes have been identified in many insect species, but presently only three aquaporins have been characterized in phloem feeding insects. The objective of this study was to identify candidate AQPs in the potato psyllid, Bactericera cockerelli. Herein, we identified four candidate aquaporin cDNAs in B. cockerelli transcriptome. Phylogenetic analysis showed that candidate BcAQP2-like had high similarity to PRIP aquaporins; while candidates BcAQP4-like, BcAQP5-like and BcAQP9-like clustered within clade B. In particular, candidates BcAQP4-like and BcAQP5-like clustered with functionally validated insect aquaglyceroporin proteins. Expression analyses using RT-qPCR showed that all candidates were expressed in all life stages and tissues. Candidates BcAQP4-like and BcAQP5-like were highly expressed in bacteriocytes, while BcAQP9-like appeared to be expressed at high levels in whole body but not in the assayed tissues. This study is the first global attempt to identify putative aquaporins in a phloem feeding insect.
Sengoda, Venkatesan G.; Cooper, W. Rodney; Swisher, Kylie D.; Henne, Donald C.; Munyaneza, Joseph E.
“Candidatus Liberibacter solanacearum” (Lso) is an economically important pathogen of solanaceous crops and the putative causal agent of zebra chip disease of potato (Solanum tuberosum L.). This pathogen is transmitted to solanaceous species by the potato psyllid, Bactericera cockerelli (Šulc), but many aspects of the acquisition and transmission processes have yet to be elucidated. The present study was conducted to assess the interacting effects of acquisition access period, incubation peri...
Sean M Prager
Full Text Available Among the many topics of interest to ecologists studying associations between phytophagous insects and their host plants are the influence of natal host plant on future oviposition decisions and the mechanisms of generalist versus specialist host selection behavior. In this study, we examined the oviposition preferences, behavior and larval development of the tomato/potato psyllid, Bactericera cockerelli. By rearing psyllids with two distinct geographically-linked haplotypes on different host plants, we were able to examine the role of natal host plant and potential local adaptation on host plant usage. Choice bioassays among three host species demonstrated that psyllids from California had clear preferences that were influenced by natal plant. We further found that patterns in choice bioassays corresponded to observed feeding and movement responses. No-choice bioassays demonstrated that there is little to no association between development and host-plant choice for oviposition, while also indicating that host choice varies between haplotypes. These findings support the concept that mothers do not always choose oviposition sites optimally and also add support for the controversial Hopkins' host selection principle.
Venkatesan G Sengoda
Full Text Available "Candidatus Liberibacter solanacearum" (Lso is an economically important pathogen of solanaceous crops and the putative causal agent of zebra chip disease of potato (Solanum tuberosum L.. This pathogen is transmitted to solanaceous species by the potato psyllid, Bactericera cockerelli (Šulc, but many aspects of the acquisition and transmission processes have yet to be elucidated. The present study was conducted to assess the interacting effects of acquisition access period, incubation period, and host plant on Lso titer in psyllids, the movement of Lso from the alimentary canal to the salivary glands of the insect, and the ability of psyllids to transmit Lso to non-infected host plants. Following initial pathogen acquisition, the probability of Lso presence in the alimentary canal remained constant from 0 to 3 weeks, but the probability of Lso being present in the salivary glands increased with increasing incubation period. Lso copy numbers in psyllids peaked two weeks after the initial pathogen acquisition and psyllids were capable of transmitting Lso to non-infected host plants only after a two-week incubation period. Psyllid infectivity was associated with colonization of insect salivary glands by Lso and with Lso copy numbers >10,000 per psyllid. Results of our study indicate that Lso requires a two-week latent period in potato psyllids and suggest that acquisition and transmission of Lso by psyllids follows a pattern consistent with a propagative, circulative, and persistent mode of transmission.
Full Text Available "Candidatus Liberibacter solanacearum" (Lso is an emergent pathogen of carrots in Europe and solanaceous plants in North and Central America and New Zealand. This bacterium is closely related to other pathogenic Candidatus Liberibacter spp., all vectored by psyllids. In order to understand the molecular interaction of this pathogen and its psyllid vector, Bactericera cockerelli, Illumina sequencing of psyllid harboring Lso was performed to determine if this approach could be used to assess the bacterial transcriptome in this association. Prior to sequencing, psyllid RNA was purified and insect and bacterial rRNA were removed. Mapping of reads to Lso genome revealed that over 92% of the bacterial genes were expressed in the vector, and that the COG categories Translation and Post-translational modification, protein turnover, chaperone functions were the most expressed functional categories. Expression levels of selected Lso genes were confirmed by RT-qPCR. The transcriptomic analysis also helped correct Lso genome annotation by identifying the expression of genes that were not predicted in the genome sequencing effort.
Glenda L Torres
Full Text Available "Candidatus Liberibacter solanacearum" (Proteobacteria is an important pathogen of solanaceous crops (Solanales: Solanaceae in North America and New Zealand, and is the putative causal agent of zebra chip disease of potato. This phloem-limited pathogen is transmitted to potato and other solanaceous plants by the potato psyllid, Bactericera cockerelli (Hemiptera: Triozidae. While some plants in the Convolvulaceae (Solanales are also known hosts for B. cockerelli, previous efforts to detect Liberibacter in Convolvulaceae have been unsuccessful. Moreover, studies to determine whether Liberibacter can be acquired from these plants by B. cockerelli are lacking. The goal of this study was to determine whether horizontal transmission of Liberibacter occurs among potato psyllids on two species of Convolvulaceae, sweet potato (Ipomoea batatas and field bindweed (Convolvulus arvensis, which grows abundantly in potato growing regions of the United States. Results indicated that uninfected psyllids acquired Liberibacter from both I. batatas and C. arvensis if infected psyllids were present on plants concurrently with the uninfected psyllids. Uninfected psyllids did not acquire Liberibacter from plants if the infected psyllids were removed from the plants before the uninfected psyllids were allowed access. In contrast with previous reports, PCR did detect the presence of Liberibacter DNA in some plants. However, visible amplicons were faint and did not correspond with acquisition of the pathogen by uninfected psyllids. None of the plants exhibited disease symptoms. Results indicate that horizontal transmission of Liberibacter among potato psyllids can occur on Convolvulaceae, and that the association between Liberibacter and Convolvulaceae merits additional attention.
Use of Electrical Penetration Graph Technology to Examine Transmission of ‘Candidatus Liberibacter solanacearum’ to Potato by Three Haplotypes of Potato Psyllid (Bactericera cockerelli; Hemiptera: Triozidae)
Mustafa, Tariq; Horton, David R.; Cooper, W. Rodney; Swisher, Kylie D.; Zack, Richard S.; Pappu, Hanu R.; Munyaneza, Joseph E.
The potato psyllid, Bactericera cockerelli (Šulc) (Hemiptera: Triozidae), is a vector of the phloem-limited bacterium ‘Candidatus Liberibacter solanacearum’ (Lso), the putative causal agent of zebra chip disease of potato. Little is known about how potato psyllid transmits Lso to potato. We used electrical penetration graph (EPG) technology to compare stylet probing behaviors and efficiency of Lso transmission of three haplotypes of potato psyllid (Central, Western, Northwestern). All haploty...
Cooper, W. Rodney; Garczynski, Stephen F.; Horton, David R.
Carsonella ruddii (Gamma Proteobacterium) is an obligate bacterial endosymbiont of psyllids that produces essential amino acids that are lacking in the insect’s diet. Accurate estimations of Carsonella populations are important to studies of Carsonella-psyllid interactions and to developing ways to target Carsonella for control of psyllid pests including pear psylla, Cacopsylla pyricola (Förster) (Hemiptera: Psyllidae) and potato psyllid, Bactericera cockerelli (Šulc) (Hemiptera: Triozidae). ...
García Negroe, Cristino Baruch
El estado de Sinaloa es el primer productor de hortalizas en México, destacan los cultivos de chile (Capsicum annuum), papa (Solanum tuberosum) y tomate (Lycopersicon esculentum). Estos cultivos representan una de las principales actividades económicas, no obstante, durante el ciclo otoño-invierno 2005-2006 se vieron afectados por enfermedades fitoplásmicas que provocaron pérdidas económicas severas al productor. Dichas enfermedades son transmitidas por insectos, por lo que ...
Munyaneza, Joseph E; Mustafa, Tariq; Fisher, Tonja W; Sengoda, Venkatesan G; Horton, David R
'Candidatus Liberibacter solanacearum' (Lso) is a phloem-limited bacterium that severely affects important Solanaceae and Apiaceae crops, including potato, tomato, pepper, tobacco, carrot and celery. This bacterium is transmitted to solanaceous species by potato psyllid, Bactericera cockerelli, and to Apiaceae by carrot psyllids, including Trioza apicalis and Bactericera trigonica. Five haplotypes of Lso have so far been described, two are associated with solanaceous species and potato psyllids, whereas the other three are associated with carrot and celery crops and carrot psyllids. Little is known about cross-transmission of Lso to carrot by potato psyllids or to potato by carrot psyllids. Thus, the present study assessed whether potato psyllid can transmit Lso to carrot and whether Lso haplotypes infecting solanaceous species can also infect carrot and lead to disease symptom development. In addition, the stylet probing behavior of potato psyllid on carrot was assessed using electropenetrography (EPG) technology to further elucidate potential Lso transmission to Apiaceae by this potato insect pest. Results showed that, while potato psyllids survived on carrot for several weeks when confined on the plants under controlled laboratory and field conditions, the insects generally failed to infect carrot plants with Lso. Only three of the 200 carrot plants assayed became infected with Lso and developed characteristic disease symptoms. Lso infection in the symptomatic carrot plants was confirmed by polymerase chain reaction assay and Lso in the carrots was determined to be of the haplotype B, which is associated with solanaceous species. EPG results further revealed that potato psyllids readily feed on carrot xylem but rarely probe into the phloem tissue, explaining why little to no Lso infection occurred during the controlled laboratory and field cage transmission trials. Results of our laboratory and field transmission studies, combined with our EPG results, suggest
Cooper, W Rodney; Garczynski, Stephen F; Horton, David R
Carsonella ruddii (Gamma Proteobacterium) is an obligate bacterial endosymbiont of psyllids that produces essential amino acids that are lacking in the insect's diet. Accurate estimations of Carsonella populations are important to studies of Carsonella-psyllid interactions and to developing ways to target Carsonella for control of psyllid pests including pear psylla, Cacopsylla pyricola (Förster) (Hemiptera: Psyllidae) and potato psyllid, Bactericera cockerelli (Šulc) (Hemiptera: Triozidae). We used two methods, namely fluorescence in situ hybridization and quantitative polymerase chain reaction (qPCR), to estimate relative abundance of Carsonella in bacteriocytes and whole bodies of psyllids, respectively. Using these two methods, we compared Carsonella populations between female and male insects. Estimations using fluorescence in situ hybridization indicated that Carsonella was more abundant in bacteriocytes of female C. pyricola than in those of males, but Carsonella abundance in bacteriocytes did not differ between sexes of B. cockerelli. Analyses by qPCR using whole-body specimens indicated Carsonella was more abundant in females than in males of both psyllids. Neither fluorescence in situ hybridization nor qPCR indicated that Carsonella populations differed in abundance among adults of different ages (0-3 wk after adult eclosion). Using fluorescence in situ hybridization, Carsonella was observed in ovarioles of newly emerged females and formed an aggregation in the posterior end of mature oocytes. Results of our study indicate that female psyllids harbor greater populations of Carsonella than do males and that sex should be controlled for in studies which require estimations of Carsonella populations. PMID:26056318
Use of Electrical Penetration Graph Technology to Examine Transmission of 'Candidatus Liberibacter solanacearum' to Potato by Three Haplotypes of Potato Psyllid (Bactericera cockerelli; Hemiptera: Triozidae.
Full Text Available The potato psyllid, Bactericera cockerelli (Šulc (Hemiptera: Triozidae, is a vector of the phloem-limited bacterium 'Candidatus Liberibacter solanacearum' (Lso, the putative causal agent of zebra chip disease of potato. Little is known about how potato psyllid transmits Lso to potato. We used electrical penetration graph (EPG technology to compare stylet probing behaviors and efficiency of Lso transmission of three haplotypes of potato psyllid (Central, Western, Northwestern. All haplotypes exhibited the full suite of stylet behaviors identified in previous studies with this psyllid, including intercellular penetration and secretion of the stylet pathway, xylem ingestion, and phloem activities, the latter comprising salivation and ingestion. The three haplotypes exhibited similar frequency and duration of probing behaviors, with the exception of salivation into phloem, which was of higher duration by psyllids of the Western haplotype. We manipulated how long psyllids were allowed access to potato ("inoculation access period", or IAP to examine the relationship between phloem activities and Lso transmission. Between 25 and 30% of psyllids reached and salivated into phloem at an IAP of 1 hr, increasing to almost 80% of psyllids as IAP was increased to 24 h. Probability of Lso-transmission was lower across all IAP levels than probability of phloem salivation, indicating that a percentage of infected psyllids which salivated into the phloem failed to transmit Lso. Logistic regression showed that probability of transmission increased as a function of time spent salivating into the phloem; transmission occurred as quickly as 5 min following onset of salivation. A small percentage of infected psyllids showed extremely long salivation events but nonetheless failed to transmit Lso, for unknown reasons. Information from these studies increases our understanding of Lso transmission by potato psyllid, and demonstrates the value of EPG technology in
Psyllids (Hemiptera: Pyslloidea) harbor bacterial symbionts in specialized organs called bacteriomes. Bacteriomes may be subject to manipulation to control psyllid pests including Bactericera cockerelli (Sulc) (Hemiptera: Triozidae) and Cacopsylla pyricola (Forster) (Hemiptera: Psyllidae) if the bi...
Casteel, Clare L.; Hansen, Allison K.; Walling, Linda L.; Paine, Timothy D.
Some plant pathogens form obligate relationships with their insect vector and are vertically transmitted via eggs analogous to insect endosymbionts. Whether insect endosymbionts manipulate plant defenses to benefit their insect host remains unclear. The tomato psyllid, Bactericerca cockerelli (Sulc), vectors the endosymbiont “Candidatus Liberibacter psyllaurous” (Lps) during feeding on tomato (Solanum lycopersicum L.). Lps titer in psyllids varied relative to the psyllid developmental stage w...
Clare L Casteel
Full Text Available Some plant pathogens form obligate relationships with their insect vector and are vertically transmitted via eggs analogous to insect endosymbionts. Whether insect endosymbionts manipulate plant defenses to benefit their insect host remains unclear. The tomato psyllid, Bactericerca cockerelli (Sulc, vectors the endosymbiont "Candidatus Liberibacter psyllaurous" (Lps during feeding on tomato (Solanum lycopersicum L.. Lps titer in psyllids varied relative to the psyllid developmental stage with younger psyllids harboring smaller Lps populations compared to older psyllids. In the present study, feeding by different life stages of B. cockerelli infected with Lps, resulted in distinct tomato transcript profiles. Feeding by young psyllid nymphs, with lower Lps levels, induced tomato genes regulated by jasmonic acid (JA and salicylic acid (SA (Allene oxide synthase, Proteinase inhibitor 2, Phenylalanine ammonia-lyase 5, Pathogenesis-related protein 1 compared to feeding by older nymphs and adults, where higher Lps titers were found. In addition, inoculation of Lps without insect hosts suppressed accumulation of these defense transcripts. Collectively, these data suggest that the endosymbiont-like pathogen Lps manipulates plant signaling and defensive responses to benefit themselves and the success of their obligate insect vector on their host plant.
The potato/tomato psyllid, Bactericera cockerelli (Sulc) (Hemiptera: Triozidae) is a major pest of solanaceous crops. This pest causes yield loss by direct feeding on crop plants and by transmitting a bacterial pathogen known as Candidatus Liberibacter psyllaurous (a. k. a. Ca. L. solanacearum). The goal of my research is to improve pest management against this pest in potatoes by integrating sampling, insecticides, use of resistant varieties, and biological control. Sampling plans are essent...
María Berenice González Maldonado; Cipriano García Gutiérrez
In Sinaloa the vegetable and cucurbits production are important agricultural activities, so each year a high volume of chemicalinsecticides are applied to pest control that attack these crops. This paper present the main pests insects in the region, as wellas an analysis about effects of biorational insecticides on these pests. Was found that for control of Bemisia argentifolii Bellows & Perring (Hemiptera: Aleyrodidae) is used Neem oil 0.2%., for kill nymphs of Bactericera cockerelli Sulc. (...
Tonja W. Fisher; Meenal Vyas; Ruifeng He; William Nelson; Joseph M. Cicero; Mark Willer; Ryan Kim; Robin Kramer; Greg A. May; John A. Crow; Soderlund, Carol A.; Gang, David R.; Brown, Judith K.
The potato psyllid (PoP) Bactericera cockerelli (Sulc) and Asian citrus psyllid (ACP) Diaphorina citri Kuwayama are the insect vectors of the fastidious plant pathogen, Candidatus Liberibacter solanacearum (CLso) and Ca. L. asiaticus (CLas), respectively. CLso causes Zebra chip disease of potato and vein-greening in solanaceous species, whereas, CLas causes citrus greening disease. The reliance on insecticides for vector management to reduce pathogen transmission has increased interest in alt...
Wuriyanghan, Hada; Rosa, Cristina; Falk, Bryce W.
The potato/tomato psyllid, Bactericerca cockerelli (B. cockerelli), and the Asian citrus psyllid, Diaphorina citri (D. citri), are very important plant pests, but they are also vectors of phloem-limited bacteria that are associated with two devastating plant diseases. B. cockerelli is the vector of Candidatus Liberibacter psyllaurous (solanacearum), which is associated with zebra chip disease of potatoes, and D. citri is the vector of Ca. Liberibacter asiaticus, which is associated with the H...
Ebie, Jessica D.; Hölldobler, Bert; Liebig, Jürgen
Although workers in many ant species are capable of producing their own offspring, they generally rear the queen's offspring instead. There are various mechanisms that regulate worker reproduction including inhibitory effects of ant brood. Colonies of the ant Novomessor cockerelli are monogynous and polydomous resulting in a large portion of nest workers being physically isolated from the queen for extended periods of time. Some workers experimentally isolated from the queen in laboratory nests lay viable eggs, which develop into males. We investigate the mechanism that regulates worker fertility in subnests separated from the queen by giving queenless worker groups queen-produced larvae, queen-produced eggs, or no brood. Our findings show that larvae delay the time to worker egg-laying, but eggs have no effect. Larval inhibition is a likely mechanism that contributes to the regulation of worker reproduction in N. cockerellli because larvae are easily transported to subnests that do not contain a queen.
A Novel Study of Interactions of Arabidopsis thaliana With Candidatus Liberibacter psyllaurous When Transmitted by psyllid Bactericera cockerelli to Develop a Chemical Genomics Based Approach That can aid in Development of Control Strategies for Huanglongbing Disease in Citrus
Huanglongbing (HLB) is a bacterial disease associated with Candidatus Liberibacter asiaticus (CLas), Candidatus Liberibacter americanus, and Candidatus Liberibacter africanus. These bacterial species are transmitted by hemipteran psyllids. For many years, this disease has caused substantial damage to citrus around the world and in recent years, it has significantly impacted citrus production in the U.S.A. The lack of effective control and curative measures against psyllids and the pathogen ar...
Full Text Available The potato/tomato psyllid, Bactericerca cockerelli (B. cockerelli, and the Asian citrus psyllid, Diaphorina citri (D. citri, are very important plant pests, but they are also vectors of phloem-limited bacteria that are associated with two devastating plant diseases. B. cockerelli is the vector of Candidatus Liberibacter psyllaurous (solanacearum, which is associated with zebra chip disease of potatoes, and D. citri is the vector of Ca. Liberibacter asiaticus, which is associated with the Huanglongbing (citrus greening disease that currently threatens the entire Florida citrus industry. Here we used EST sequence information from D. citri to identify potential targets for RNA interference in B. cockerelli. We targeted ubiquitously expressed and gut-abundant mRNAs via injection and oral acquisition of double-stranded RNAs and siRNAs and were able to induce mortality in recipient psyllids. We also showed knockdown of target mRNAs, and that oral acquisition resulted primarily in mRNA knockdown in the psyllid gut. Concurrent with gene knockdown was the accumulation of target specific ∼ 21 nucleotide siRNAs for an abundant mRNA for BC-Actin. These results showed that RNAi can be a powerful tool for gene function studies in psyllids, and give support for continued efforts for investigating RNAi approaches as possible tools for psyllid and plant disease control.
Mohammad H. Kazemi; Mohammad M. Jafarloo
Problem statement: Psyllids as a small group of insects with plant feeding adult and nymphal stages, not only could have direct feeding damages but they could also transmit plant diseases especially viruses. Bactericera tremblayi had recently increased to high densities in onion fields in East Azarbaijan province in Iran and the pest had become widespread. This was the first study of the biology of the pest in Iran and probably in the world. Approach: After ...
The fastidious prokaryote Candidatus Liberibacter solanacearum (Lso), transmitted by the tomato potato psyllid (Bactericera cockerelli), is associated with the Zebra Chip disease of potato. Plants infected with Liberibacter may experience significant yield losses and these plants also serve as poten...
The fastidious prokaryote Candidatus Liberibacter solanacearum (Lso), transmitted by the tomato potato psyllid (Bactericera cockerelli), is associated with the Zebra Chip disease of potato. Plants infected with Liberibacter may experience significant yield losses and these plants also serve as pote...
María Berenice González Maldonado
Full Text Available In Sinaloa the vegetable and cucurbits production are important agricultural activities, so each year a high volume of chemicalinsecticides are applied to pest control that attack these crops. This paper present the main pests insects in the region, as wellas an analysis about effects of biorational insecticides on these pests. Was found that for control of Bemisia argentifolii Bellows & Perring (Hemiptera: Aleyrodidae is used Neem oil 0.2%., for kill nymphs of Bactericera cockerelli Sulc. (Homoptera: Psyllidae soursop Annona muricata L. (Annonales: Annonaceae at doses of 2500-5000 mg/L., for Liriomyza trifolii Burgess (Diptera: Agromyzidae neem seeds 2%., to Myzus persicae Sulzer (Hemiptera: Aphididae rapeseed oil at doses 920 g/L (2% v/v., to Frankliniella occidentalis Pergande (Thysanoptera: Thripidae spinosad (Conserve® 48-60 mg/L., and for Phthorimaea operculella Zeller (Lepidoptera: Gelechiidae granular viruses (105 OBs/mL combined with neem (DalNeem TM emulsifiable oil and NeemAzal TM -T/S at doses of 8 mg/L, everyone. The use of these products and the dose depends on the type of pest and crop. In general these products cause insect mortality greater than 95%, besides having low toxicity on natural enemies, so that these can be used individually or in combination in integrated pest control schemes against vegetable pests, and also for disease vectors insects in the northern of Sinaloa.
Tonja W. Fisher
Full Text Available The potato psyllid (PoP Bactericera cockerelli (Sulc and Asian citrus psyllid (ACP Diaphorina citri Kuwayama are the insect vectors of the fastidious plant pathogen, Candidatus Liberibacter solanacearum (CLso and Ca. L. asiaticus (CLas, respectively. CLso causes Zebra chip disease of potato and vein-greening in solanaceous species, whereas, CLas causes citrus greening disease. The reliance on insecticides for vector management to reduce pathogen transmission has increased interest in alternative approaches, including RNA interference to abate expression of genes essential for psyllid-mediated Ca. Liberibacter transmission. To identify genes with significantly altered expression at different life stages and conditions of CLso/CLas infection, cDNA libraries were constructed for CLso-infected and -uninfected PoP adults and nymphal instars. Illumina sequencing produced 199,081,451 reads that were assembled into 82,224 unique transcripts. PoP and the analogous transcripts from ACP adult and nymphs reported elsewhere were annotated, organized into functional gene groups using the Gene Ontology classification system, and analyzed for differential in silico expression. Expression profiles revealed vector life stage differences and differential gene expression associated with Liberibacter infection of the psyllid host, including invasion, immune system modulation, nutrition, and development.
Host range testing of Tamarixia radiata (Hymenoptera: Eulophidae) sourced from the Punjab of Pakistan for classical biological control of Diaphorina citri (Hemiptera: Liviidae: Euphyllurinae: Diaphorinini) in California.
Hoddle, Mark S; Pandey, Raju
ABSTRACT Tests evaluating the host range of Tamarixia radiata (Waterson) (Hymenoptera: Eulophidae), a parasitoid of the pestiferous Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Liviidae), sourced from the Punjab of Pakistan, were conducted in quarantine at the University of California, Riverside, CA. Seven nontarget psyllid species (five native and two self-introduced species) representing five families were exposed to T radiata under the following three different exposure scenarios: 1) sequential no-choice tests, 2) static no-choice tests, and 3) choice tests. Nontarget species were selected for testing based on the following criteria: 1) taxonomic relatedness to the target, D. citri; 2) native psyllids inhabiting native host plants related to citrus that could release volatiles attractive to T. radiata; 3) native psyllids with a high probability of occurrence in native vegetation surrounding commercial citrus groves that could be encountered by T. radiata emigrating from D. citri-infested citrus orchards; 4) a common native pest psyllid species; and 5) a beneficial psyllid attacking a noxious weed. The results of host range testing were unambiguous; T radiata exhibited a narrow host range and high host specificity, with just one species of nontarget psyllid, the abundant native pest Bactericera cockerelli Sulc, being parasitized at low levels (control of D. citri poses negligible environmental risk. PMID:24665694
Full Text Available Zebra Chip (ZC is an emerging plant disease that causes aboveground decline of potato shoots and generally results in unusable tubers. This disease has led to multi-million dollar losses for growers in the central and western United States over the past decade and impacts the livelihood of potato farmers in Mexico and New Zealand. ZC is associated with 'Candidatus Liberibacter solanacearum', a fastidious alpha-proteobacterium that is transmitted by a phloem-feeding psyllid vector, Bactericera cockerelli Sulc. Research on this disease has been hampered by a lack of robust culture methods and paucity of genome sequence information for 'Ca. L. solanacearum'. Here we present the sequence of the 1.26 Mbp metagenome of 'Ca. L. solanacearum', based on DNA isolated from potato psyllids. The coding inventory of the 'Ca. L. solanacearum' genome was analyzed and compared to related Rhizobiaceae to better understand 'Ca. L. solanacearum' physiology and identify potential targets to develop improved treatment strategies. This analysis revealed a number of unique transporters and pathways, all potentially contributing to ZC pathogenesis. Some of these factors may have been acquired through horizontal gene transfer. Taxonomically, 'Ca. L. solanacearum' is related to 'Ca. L. asiaticus', a suspected causative agent of citrus huanglongbing, yet many genome rearrangements and several gene gains/losses are evident when comparing these two Liberibacter. species. Relative to 'Ca. L. asiaticus', 'Ca. L. solanacearum' probably has reduced capacity for nucleic acid modification, increased amino acid and vitamin biosynthesis functionalities, and gained a high-affinity iron transport system characteristic of several pathogenic microbes.
Full Text Available Plants produce specific volatile organic compound (VOC blends in response to herbivory. Herbivore-induced blends may prime the plant for future attack or attract carnivorous insects; these responses have been considered adaptive for plants. If herbivores differentially modify the VOC emission among individuals within a group of plants they feed upon, then plant responses to herbivores will not only produce specific blends but also variation in odor among individuals, i.e. individuals smell the same, then having a uniform odor. We investigated the VOC emission variation or uniformity among tomato individuals (Solanum lycopersicum L. cv. Castlemart in response to moderate wounding by (1 nymphs of the psyllid Bactericera cockerelli (Sulc. (TP; (2 Lepidoptera chewing-feeding larvae of Fall Armyworm (Spodoptera frugiperda Smith (FAW and (3 of Cabbage Looper (Trichoplusia ni Hübner (CL, and (4 mechanical damage (MD. We used a ratio-based analysis to compare the fold-change in concentration from constitutive to induced VOC emission. We also used size and shape analysis to compare the emission of damaged and non-damaged individuals. Aside of finding herbivore-specific blends in line with other studies, we found patterns not described previously. We detected constitutive and induced odor variation among individuals attacked by the same herbivore, with the induced odor uniformity depending on the herbivore identity. We also showed that the fold-change of VOCs from constitutive to induced state differed among individuals independently of the uniformity of the blends before herbivore attack. We discuss our findings in the context of the ecological roles of VOCs in plant-plant and plant-carnivore insects' interactions.
DEGUANG LIU; LINDSEY JOHNSON; JOHN T. TRUMBLE
An invasive new biotype of the tomato/potato psyllid (Bactericera [Paratrioza] cockerelli [Sulc.]) (Homoptera: Psyllidae) recently has caused losses exceeding 50% on fresh market tomatoes in western North America. Despite these extensive losses, little is known regarding the threshold levels at which populations must be suppressed in order to prevent economic losses. A series of experiments were therefore designed using combinations of two common tomato cultivars (QualiT 21 and Yellow Pear), five pest-densities (0, 20, 30, 40 and 50 nymphs/plant), and three feeding-duration (5 days, 10 days, and lifetime) treatments to test the relative importance of pest density, feeding period, and cumulative psyllid-days to establish economic threshold levels for psyllids. The cultivars differed considerably in their response to the toxin injected by the psyllid nymphs. 'Yellow Pear' plants could recover from feeding by up to 40 nymphs for as long as 10 d, whereas 'QualiT 21' plants were irreparably damaged by densities of 20 nymphs feeding for only 5 days. On 'Yellow Pear', all plant measurements such as the number of yellow leaves and plant height were significantly better correlated with cumulative psyllid-days than with either pest density or feeding duration. On 'QualiT 21', all plant measurements other than the number of yellow leaflets and leaves were significantly better correlated with pest density than with feeding duration or cumulative psyllid-days, and pest density was a better predictor of psyllid damage. Potential reasons for the variable responses between cultivars and the implications for psyllid sampling and integrated pest management are discussed.
Wu, F; X. Deng; Liang, G.; Wallis, C; Trumble, J T; Prager, S; Chen, J.
The draft genome sequence of “Candidatus Liberibacter solanacearum” strain RSTM from a potato psyllid (Bactericera cockerelli) in California is reported here. The RSTM strain has a genome size of 1,286,787 bp, a G+C content of 35.1%, 1,211 predicted open reading frames (ORFs), and 43 RNA genes.
Zebra chip disease (ZC), which is caused by ‘Candidatus Liberibacter solanacearum’ (Lso) and vectored by potato psyllids Bactericera cockerelli, is a continuing threat to the North American potato industry. Current management entails frequent insecticide sprays for the vectors as thresholds for spra...
The draft genome sequence of “Candidatus Liberibacter solanacearum” strain RSTM from a potato psyllid (Bactericera cockerelli) in California is reported. The RSTM strain has the genome size of 1,286,787 bp, GC content of 35.1%, 1,211 predicted open reading frames (ORFs), and 43 RNA genes....
The potato psyllid, Bactericera cockerelli (Šulc), is a vector of the bacterium ‘Candidatus Liberibacter solanacearum’ (Lso) that has been linked to the economically devastating zebra chip disease of potato. To date, four haplotypes of the potato psyllid have been identified and include Central, We...
The potato psyllid (Bactericera cockerelli) is a Hemipteran pest of solanaceous plants and limits potato and tomato production by the transmission of Candidatus Liberibacter solanacearum. Genomic information on the potato psyllid is limited but is vital in developing appropriate management strategi...
The potato psyllid (Bactericera cockerelli) is a Hemipteran pest of solanaceous plants and limits potato and tomato production by the transmission of Candidatus Liberibacter solanacearum. Genomic information on the potato psyllid is limited but is vital in developing appropriate management strategi...
“Candidatus Liberibacter solanacearum” is an important pathogen of Solanaceous crops that causes zebra chip disease of potato. This pathogen is transmitted among plants by the potato psyllid Bactericera cockerelli. Within-plant variability in Liberibacter infection impedes the ability to detect Lib...
Fisher, T.; R. He; Nelson, W; Vyas, M; Willer, M.; Soderlund, C.; Gang, D.; Brown, J. K.
Citrus greening is the most destructive disease of citrus crops worldwide. The introduced Asian citrus psyllid (ACP) Diaphorina citri Kuwayama transmits the (putative) causal bacterium, Candidatus Liberibacter asiaticus. A close relative, Ca. L. solanacearum, is the pathogen associated with Zebra chip disease of potato and vein-greening disease of tomato. It is both transmitted by and propagative in the endemic (western U.S) potato psyllid (PoP) Bactericerca cockerelli Sulc. The PoP occurs wi...
Alvarado, Veria Y.; Odokonyero, Denis; Duncan, Olivia; Mirkov, T. Erik; Scholthof, Herman B.
Zebra complex (ZC) disease on potatoes is associated with Candidatus Liberibacter solanacearum (CLs), an α-proteobacterium that resides in the plant phloem and is transmitted by the potato psyllid Bactericera cockerelli (Šulc). The name ZC originates from the brown striping in fried chips of infected tubers, but the whole plants also exhibit a variety of morphological features and symptoms for which the physiological or molecular basis are not understood. We determined that compared to health...
Díaz Valasis, Margarita
El cultivo de la papa ha sido afectado por una enfermedad que induce el pardeamiento y la brotación anormal en el tubérculo, a ésta se le ha denominado punta morada de la papa (PMP). La PMP, asociada con un fitoplasma y Bactericera (Paratrioza) cockerelli, se han encontrado relacionadas con este síndrome, son de importancia mundial y se presentan en las principales zonas paperas de México. El objetivo de esta investigación fue dilucidar con más precisión los agentes causa...
Tzin, Vered; Yang, Xiaowei; Jing, Xiangfeng; Zhang, Kai; Jander, Georg; Douglas, Angela E
In planta RNAi (i.e. plants engineered to synthesize active RNAi molecules) has great potential as a strategy to control insect crop pests. This study investigated the impact of RNAi against osmoregulatory genes expressed in the gut of two phloem-feeding species, the green peach aphid Myzus persicae and the potato/tomato psyllid Bactericera cockerelli. The target genes comprising candidate gut sucrase, aquaporin and sugar transporter genes were identified by mining insect genomic and transcriptomic datasets for genes orthologous to empirically-tested osmoregulatory genes of the pea aphid Acyrthosiphon pisum. Insects feeding on plants with RNAi against the target genes exhibited elevated hemolymph osmotic pressure (a predicted effect of perturbed osmotic function) and some reduction in performance, especially offspring production in M. persicae and mortality in B. cockerelli, associated with up to 50% reduction in mean expression of the target genes. The effects were particularly pronounced for insects treated with RNAi against multiple osmoregulatory genes, i.e. combinatorial RNAi, suggesting that the partial silencing of multiple genes with related roles can yield greater functional impairment than RNAi against a single gene. These results demonstrate the potential of RNAi against osmoregulatory genes, but further advances to improve the efficacy of RNAi in phloem-feeding insects are required to achieve effective pest control. PMID:26071792
Jing, X; White, T A; Luan, J; Jiao, C; Fei, Z; Douglas, A E
The high osmotic pressure generated by sugars in plant phloem sap is reduced in phloem-feeding aphids by sugar transformations and facilitated water flux in the gut. The genes mediating these osmoregulatory functions have been identified and validated empirically in the pea aphid Acyrthosiphon pisum: sucrase 1 (SUC1), a sucrase in glycoside hydrolase family 13 (GH13), and aquaporin 1 (AQP1), a member of the Drosophila integral protein (DRIP) family of aquaporins. Here, we describe molecular analysis of GH13 and AQP genes in phloem-feeding representatives of the four phloem-feeding groups: aphids (Myzus persicae), coccids (Planococcus citri), psyllids (Diaphorina citri, Bactericera cockerelli) and whiteflies (Bemisia tabaci MEAM1 and MED). A single candidate GH13-SUC gene and DRIP-AQP gene were identified in the genome/transcriptome of most insects tested by the criteria of sequence motif and gene expression in the gut. Exceptionally, the psyllid Ba. cockerelli transcriptome included a gut-expressed Pyrocoelia rufa integral protein (PRIP)-AQP, but has no DRIP-AQP transcripts, suggesting that PRIP-AQP is recruited for osmoregulatory function in this insect. This study indicates that phylogenetically related SUC and AQP genes may generally mediate osmoregulatory functions in these diverse phloem-feeding insects, and provides candidate genes for empirical validation and development as targets for osmotic disruption of pest species. PMID:26896054
Ravindran, Aravind; Lévy, Julien; Pierson, Elizabeth; Gross, Dennis C
An efficient loop-mediated isothermal amplification procedure (LAMP) for the detection of "Candidatus Liberibacter solanacearum" (Lso), the bacterial causal agent of potato zebra chip (ZC) disease, is described in this chapter. Similar to the polymerase chain reaction (PCR), the LAMP employs a bacterial polymerase to amplify specific DNA sequences. However, the method differs from conventional PCR in that it uses six primers specific to the target region to generate a loop structure and autocycling strand displacement rather than thermocycling for sequence amplification. Moreover, unlike PCR that requires agarose gel electrophoresis for resolution, the positive LAMP results can be visualized directly as a precipitate within the reaction tubes. The 16S rDNA gene of "Ca. Liberibacter solanacearum" was used as the target for the design of the six LAMP primers. The LAMP technique is a reliable, rapid, and cost-effective method of detecting the "Ca. Liberibacter solanacearum" pathogen in the potato/tomato psyllid, Bactericera cockerelli, and in field-grown potato plants and tubers. PMID:25981248
Xiang-Bing Yang; Nasir S. A. Malik; Jose L. Perez; Tong-Xian Liu
The impacts of potato psyllid (Bactericera cockerelli) feeding on potato foliage on the free amino acids (FAAs) composition in potato leaf and tubers were determined under greenhouse conditions.The free amino acids in plant extracts were separated by high-performance liquid chromatography,and in both leaf and tuber samples,at least 17 FAAs were detected.Psyllid feeding significantly changed the levels of several FAAs in both leaf and tuber samples.The concentration of leucine increased 1.5-fold,whereas that of serine and proline increased 2- and 3-fold,respectively.In contrast,the concentrations of glutamic acid,aspartic acid and lyscine were significantly reduced by 42.0％,52.1％ and 27.5％,respectively.There were also significant changes in the levels of FAAs in the Zebra chip (ZC) infected tubers compared with the healthy tubers,and the levels of six of the FAAs increased,and the levels of nine of the FAAs decreased.The results from this study indicate that potato psyllid causes major changes in free amino acid composition of plant tissues,and this change in plant metabolism may contribute to the plant stress as indicated by increased levels of proline in the leaves and hence promoting the development of plant diseases such as ZC disease.
Thomas Seth Davis
Full Text Available Although bacterial endosymbioses are common among phloeophagous herbivores, little is known regarding the effects of symbionts on herbivore host selection and population dynamics. We tested the hypothesis that plant selection and reproductive performance by a phloem-feeding herbivore (potato psyllid, Bactericera cockerelli is mediated by infection of plants with a bacterial endosymbiont. We controlled for the effects of herbivory and endosymbiont infection by exposing potato plants (Solanum tuberosum to psyllids infected with "Candidatus Liberibacter solanacearum" or to uninfected psyllids. We used these treatments as a basis to experimentally test plant volatile emissions, herbivore settling and oviposition preferences, and herbivore population growth. Three important findings emerged: (1 plant volatile profiles differed with respect to both herbivory and herbivory plus endosymbiont infection when compared to undamaged control plants; (2 herbivores initially settled on plants exposed to endosymbiont-infected psyllids but later defected and oviposited primarily on plants exposed only to uninfected psyllids; and (3 plant infection status had little effect on herbivore reproduction, though plant flowering was associated with a 39% reduction in herbivore density on average. Our experiments support the hypothesis that plant infection with endosymbionts alters plant volatile profiles, and infected plants initially recruited herbivores but later repelled them. Also, our findings suggest that the endosymbiont may not place negative selection pressure on its host herbivore in this system, but plant flowering phenology appears correlated with psyllid population performance.
Cicero, J M; Fisher, T W; Brown, J K
The potato psyllid Bactericera cockerelli is implicated as the vector of the causal agent of zebra chip of potato and vein-greening of tomato diseases. Until now, visual identification of bacteria in the genus 'Candidatus Liberibacter' has relied on direct imaging by light and electron microscopy without labeling, or with whole-organ fluorescence labeling only. In this study, aldehyde fixative followed by a coagulant fixative, was used to process adult psyllids for transmission electron microscopy (TEM) colloidal gold in situ hybridization experiments. Results indicated that 'Ca. Liberibacter solanacearum' (CLso)-specific DNA probes annealed to a bacterium that formed extensive, monocultural biofilms on gut, salivary gland, and oral region tissues, confirming that it is one morphotype of potentially others, that is rod-shaped, approximately 2.5 µm in diameter and of variable length, and has a rough, granular cytosol. In addition, CLso, prepared from shredded midguts, and negatively stained for TEM, possessed pili- and flagella-like surface appendages. Genes implicating coding capacity for both types of surface structures are encoded in the CLso genome sequence. Neither type was seen for CLso associated with biofilms within or on digestive organs, suggesting that their production is stimulated only in certain environments, putatively, in the gut during adhesion leading to multiplication, and in hemolymph to afford systemic invasion. PMID:26551449
Feng Gao; John Jifon; Xiangbing Yang; Tong-Xian Liu
The Zebra chip (ZC) syndrome is an emerging disease of potato and a major threat to the potato industry.The potato psyllid,Bactericerca cockerelli (Sulc) is believed to be a vector of the ZC pathogen,which is now thought to be Candidatus Liberibacter,a bacterium.To further understand the relationship between potato psyllid infestation and ZC disease expression,healthy potato plants at different growth stages (4,6 and 10 weeks after germination) were exposed separately to potato psyllids that were separately reared on four solanaceons hosts plants (potato,tomato,eggplant or bell pepper) for more than 1 year.ZC symptoms,leaf rates and total nonstructural carbohydrate accumulation in leaves and tubers of healthy and psyllid-infested plants were monitored and recorded.Typical ZC symptoms were observed in leaves and tubers of all plants exposed to potato psyllids regardless of the host plant on which they were reared.This was also accompanied by significant reductions in net photosynthetic rate.Caged potato plants without exposure to potato psyllids (uninfested controls) did not show any ZC symptom in both foliage and in harvested tubers.Foliage damage and ZC expression were most severe in the potato plants that were exposed to potato psyllids 4 weeks after germination compared to plants infested at later growth stages.Tubers from potato psyllid-infested plants had significantly higher levels of reducing sugars (glucose) and lower levels of starch than those in healthy plants,indicating that potato psyllid infestation interfered with carbohydrate metabolism in either leaves or tubers,resulting in ZC expression.
Veria Y Alvarado
Full Text Available Zebra complex (ZC disease on potatoes is associated with Candidatus Liberibacter solanacearum (CLs, an α-proteobacterium that resides in the plant phloem and is transmitted by the potato psyllid Bactericera cockerelli (Šulc. The name ZC originates from the brown striping in fried chips of infected tubers, but the whole plants also exhibit a variety of morphological features and symptoms for which the physiological or molecular basis are not understood. We determined that compared to healthy plants, stems of ZC-plants accumulate starch and more than three-fold total protein, including gene expression regulatory factors (e.g. cyclophilin and tuber storage proteins (e.g., patatins, indicating that ZC-affected stems are reprogrammed to exhibit tuber-like physiological properties. Furthermore, the total phenolic content in ZC potato stems was elevated two-fold, and amounts of polyphenol oxidase enzyme were also high, both serving to explain the ZC-hallmark rapid brown discoloration of air-exposed damaged tissue. Newly developed quantitative and/or conventional PCR demonstrated that the percentage of psyllids in laboratory colonies containing detectable levels of CLs and its titer could fluctuate over time with effects on colony prolificacy, but presumed reproduction-associated primary endosymbiont levels remained stable. Potato plants exposed in the laboratory to psyllid populations with relatively low-CLs content survived while exposure of plants to high-CLs psyllids rapidly culminated in a lethal collapse. In conclusion, we identified plant physiological biomarkers associated with the presence of ZC and/or CLs in the vegetative potato plant tissue and determined that the titer of CLs in the psyllid population directly affects the rate of disease development in plants.
Rush, C M; Workneh, F; Rashed, A
Zebra chip (ZC) of potato is putatively caused by the fastidious, phloem-limited bacterium 'Candidatus Liberibacter solanacearum' (Lso), which is transmitted by the potato psyllid (Bactericera cockerelli). The disease, which significantly impacts both crop yield and quality, was first identified in the United States from south Texas in 2000. It reached epidemic levels in north Texas and certain production areas in Colorado, Nebraska, and New Mexico from 2004 to 2007 and it caused severe losses in fields in Oregon, Washington, and Idaho in 2011. The potato plant is susceptible to infection at all developmental stages, but disease management programs have focused on vector control through early and repeated insecticide applications, in an effort to minimize early to midseason infections which are most damaging. Growers often terminate spray programs 2 to 3 weeks prior to crop harvest due to lack of visible treatment effects on crop yield or quality. However, recent studies on vector transmission and host-pathogen interactions have revealed that late-season infections pose a significant, previously unrecognized, threat to crop quality. The pathogen can move from an infected leaf to tubers within 2 days; however, tubers infected less than 1 week before harvest will remain asymptomatic and the pathogen will be undetectable. When these tubers are placed into storage they are assumed to be disease free. However, Lso can continue to multiply in respiring tubers during storage, resulting in reduced tuber quality. Likewise, if plants become infected a few days before vines are killed, ZC can continue to develop in infected tubers before they are harvested. Perspectives on the significance of late-season infections and some of the more important issues associated with those infections are discussed. PMID:25894320
Tsai, Shu Fen; Lin, Chao Yuan
In 1976, "Slopeland Conservation and Utilization Act" was promulgated as well as the criteria for slopeland utilization limitation classification (SULC) i.e., average slope, effective soil depth, degree of soil erosion, and parent rock became standardized. Due to the development areas on slope land steadily increased and the extreme rainfall events occurred frequently, the areas affected by landslides also increased year by year. According to the act, the land which damaged by disaster must be categorized to the conservation land and required rehabilitation. Nevertheless, the large-scale disaster on slope land and the limitation of SWCB officers are the constraint of field investigation. Therefore, how to establish the ongoing inspective procedure of post-disaster SULC using remote sensing was essential. A-Li-Shan, Ai-Liao, and Tai-Ma-Li Watershed were selected to be case studies in this project. The spatial data from big data i.e., Digital Elevation Model (DEM), soil map, and satellite images integrated with Geographic Information Systems (GIS) were applied to post-disaster SULC. The collapse and deposition area which delineated by vegetation recovery rate was established landslide inventory of cadastral unit combined with watershed unit. The results were verified with field survey and the accuracy was 97%. The landslide inventory could be an effective reference for sediment disaster investigation and a practical evidence for judgement to expropriation. Finally, the results showed that the ongoing inspective procedure of post-disaster SULC was practicable. From the four criteria, the average slope was the major factor. It was found that the non-uniform slopes, especially derived from cadastral units, often produce significant slope difference and lead to errors of average slope evaluation. Therefore, the Grid-based DEM slope derivation has been recommended as the standard method to calculate the average slope. Others criteria were previously required to classify
Zebra chip (ZC) is an emerging destructive disease stymying potato production in several parts of the world including the U.S. The disease is associated with the phloem-limited a-protobacterium, ‘Candidatus Liberibacter solanacearum’ (Lso), which is transmitted by the potato psyllid, Bactericera coc...
Bactericera maculipennis is a native psyllid that commonly occurs on field bindweed in the western United States. We have found that Pacific Northwest populations of B. maculipennis carry Liberibacter solanacearum, the pathogen associated with zebra chip disease of potato. In North America, this p...
The comparative investigation of the morphological basis for olfactory reception in two psyllid species, Diaphorina citri (the Asian citrus psyllid), and Bacterocera cockerelli (the potato/tomato psyllid) (both species Hemiptera:Psyllidae) was performed using scanning electron microscopy to elucidat...
Smith, Adrian A.; Haight, Kevin L.
Ants that fall prey to the raids of army ants commonly respond by evacuating their nests. This documented behavior has been underexploited by researchers as an efficient research tool. This study focuses on the evacuation response of the southwestern desert ant Aphaenogaster cockerelli André (Hymenoptera: Formicidae) to the army ant Newamyrmex nigrescens Cresson. It is shown that army ants can be used to collect mature colonies of ants. The applicability of this tool to ecologically meaningfu...
Full Text Available Candidatus Liberibacter solanacearum’ has recently been reported to be associated with vegetative disorders and economic losses in carrot and celery crops in Spain. The bacterium is a carrot seedborne pathogen and it is transmitted by psyllid vector species. From 2011 to 2014 seasonal and occasional surveys in carrot, celery and potato plots were performed. The sticky plant method was used to monitor the arthropods that visited the plants. The collected arthropods were classified into Aphididae and Cicadellidae, and the superfamily Psylloidea was identified to the species level. The superfamily Psylloidea represented 35.45% of the total arthropods captured on celery in Villena and 99.1% on carrot in Tenerife (Canary Islands. The maximum flight of psyllid species was in summer, both in mainland Spain and the Canary Islands, reaching a peak of 570 specimens in August in Villena and 6,063 in July in Tenerife. The main identified psyllid species were as follows: Bactericera trigonica Hodkinson, B. tremblayi Wagnerand B. nigricornis Förster. B. trigonica represented more than 99% of the psyllids captured in the Canary Islands and 75% and 38% in 2011 and 2012 in Villena, respectively. In addition, Trioza urticae Linnaeus, Bactericera sp.,Ctenarytaina sp., Cacopsylla sp., Trioza sp. and Psylla sp. were captured. ‘Ca. L. solanacearum’ targets were detected by squash real-time PCR in 19.5% of the psyllids belonging to the different Bactericera species. This paper reports at least three new psyllid species that carry the bacterium and can be considered as potential vectors.
Choi, In-Young; Lee, Wang-Hyu; Lee, Jong-Jin; Park, Mi-Jeong; Choi, Jeong-Ran
Extensive disease surveys performed during the summers of 2013 and 2014 in Schisandra chinensis orchards resulted in the finding of a Septobasidium sp. associated with felt disease. The fungus was characterized to be symbiotic with a scale insect (Pseudaulacaspis cockerelli). Morphological and molecular characteristics of the Septobasidium isolates were investigated. The isolates were morphologically and phylogenetically close to S. bogoriense. We tentatively describe this isolate as a Septobasidium sp., mainly because of the limited amount of information available on the internal transcribed spacer region of the ribosomal DNA of Septobasidium spp. PMID:27103856
Absorção e Níveis Críticos de Fósforo na parte aérea para manutenção da produtividade do Capim-Elefante (Pennisetum purpureum cv. Napier) Phosphorus absorption and critical levels in the shoot for the elephant grass (Pennisetum purpureum cv. Napier) production maintenance
Luciano de Melo Moreira; Dilermando Miranda da Fonseca; Janaina Azevedo Martuscello; Elcivan Bento da Nóbrega
O experimento foi conduzido, em campo, durante dois anos, para avaliar o efeito residual da adubação fosfatada de implantação sobre a absorção e os valores de níveis críticos de fósforo (P) na planta para manutenção do capim-elefante (Pennisetum purpureum Schum. cv. Napier). Os tratamentos foram arranjados segundo o fatorial 2 x 2 x 5, em delineamento com blocos casualizados com três repetições, e consistiram de duas formas de aplicação de P (localizada no fundo do sulco e distribuída no sulc...
Korneyev V. A.
Full Text Available Review of the Genus Geloemyia (Diptera, Pyrgotidae, with Discussion of its Taxonomic Position. Korneyev, V. A. - Species assigned to Geloemyia Hendel, 1908, Trichempodia Malloch, 1930 syn. n., Parageloemyia Hendel, 1933 syn. n., and Dicranostira Enderlein, 1942 syn. n. are shown to be congeneric. Geloemyia is refined to include eight species: Geloemyia cheni Kim, Han & Korneyev, sp. n., Geloemyia cockerelli (Malloch, 1930 comb. n. (= Trichempodia cockerelli Malloch, 1930, Geloemyia dorsocentralis (Hering, 1940 comb. n. (= Adapsilia dorsocentralis Hering, 1940, Geloemyia quadriseta Hendel, 1933, Geloemyia stylata Hendel, 1908, Geloemyia wonjuensis (Kim & Han, 2001 comb. n. (= Parageloemyia wonjuensis Kim & Han, 2001 from Eastern Asia, Geloemyia namibica sp. n., from mainland Africa (Namibia and Geloemyia trifasciata (Enderlein, 1942 comb. n. (= Trichempodia trifasciata Enderlein, 1942 from Madagascar. Geloemyia nigrofasiata Hendel, 1933 based on a single male is supposed to be a junior synonym of G. quadriseta Hendel, 1933, based on females, but the synonymy is tentative. A key to species is provided. The genus Geloemyia belongs in the tribe Pyrgotini forming (or belonging to a basal lineage in the subtribe Adapsiliina together with Pyrgotomyia Hendel, 1914 and Porpomastix Enderlein, 1942.
Liu, Sai; Li, Jianling; Guo, Kun; Qiao, Haili; Xu, Rong; Chen, Jianmin; Xu, Changqing; Chen, Jun
Migration by attachment to insects is common among mites that live in temporary habitats. However, because plants provide relatively stable habitats, phytophagous mites are generally not dependent on other animals for dispersal, so whether these mites can consistently be phoretic on insects through a particular life stage remains unclear and controversial. Here, we describe an obligate phoresy of a wholly phytophagous mite, Aceria pallida, in which the mites accompanied the psyllid Bactericera gobica to its winter hibernation sites, thus successfully escaping unfavourable winter conditions, and returned to reach the buds of their host plant early the following spring. This finding provides evidence of a new overwintering strategy that has contributed to the evolutionary success of these tiny phytophagous mites. PMID:27150196
Full Text Available In the current study, digestive lipase activity was determined and characterized in the third larval instars of olive fly, Bactericera oleae as the first time in dipteran order. By using two sample fractions, it was found that the enzyme had higher activity in membrane-bound fraction than that of soluble fraction. Optimal pH of soluble lipase was found to be 4 and 6 but membrane-bound lipase showed pH 4 as optimal value. Optimal temperatures for soluble and membrane-bound lipase were obtained to be 35 and 50 °C, respectively. Activities of digestive soluble and membrane-bound lipases decreased by using various mono- and di-valent ions. Since, fruits of olive are full of various oils, digestive lipases of B. oleae larvae have critical role in their digestion. So, these enzymes might be a good target for developing inhibitors and resistant varieties.
Issue No. 4 of Volume 4 of the ITER Newsletter, prepared and published by the IAEA in order to disseminate news on the ITER project, reports on the following topics: (i) The fourth and final meeting of quadripartite EDA negotiators (QEN-4) on November 13 and 14, 1991 in Moscow, during which the ITER E(ngineering) D(esign) A(ctivities) Agreement was initialled, the expected ITER Council members were identified, and appreciation for the IAEA's support of the ITER project was expressed. (ii) The September meeting of the Quadripartite Engineering Design Activities Negotiators' (QEN) Working Group at the IAEA Headquarters in Vienna on September 11-13, 1991, in preparation of the aforementioned November meeting in Moscow, in which topics associated with future project implementation were addressed. (iii) The ITER Workshop on ''Radiation Effects on Diagnostic Components'', St. Petersburg, USSR, October 14-17, 1991, during which radiation issues affecting performance of diagnostic components were clarified, and during which it was confirmed that a large variety of irradiation facilities could be made available for testing of diagnostic materials. (iv) The ''ITER Magnet R and D Workshop'', September 23-27, 1991, at Naka Fusion Research Establishment, JAERI, Japan, during which preliminary designs and test programmes for C(entral) S(olenoid) and T(oroidal) F(ield) model coils were reported, and various approaches to the TF model coil's tests were presented and discussed. The plan for magnet R and D was reviewed. (v) The ITER Neutral Beam Heating, held in Moscow, October 21-23, 1991, during which the status of the neutral beam development was reviewed. The plan was formed to evolve common designs for the E(lectro) S(tatic) and E(lectro) S(tatic) Q(uadrupole) negative ion beams accelerator concepts. (vi) A two-page overview by V. Sulc of the research activity on the LiPb blanket for ITER in the nuclear research institute, REZ, CSFR
Phenacoccinae de Centro y Sudamérica (Hemiptera: Coccoidea: Pseudococcidae: Sistemática y Filogenia Central and South American Phenacoccinae (Hemiptera: Coccoidea: Pseudococcidae: Systematics and Phylogeny
María Cristina Granara De Willink
Full Text Available Se presenta un estudio sistemático y cladístico de las especies de Phenacoccus Cockerell neotropicales. Se describen e ilustran 18 especies nuevas: Phenacoccus argentinus Granara de Willink, Ph. berberis Granara de Willink, Ph. chubutensis Granara de Willink, Ph. ornatus Granara de Willink, Ph. persimilis Granara de Willink (Argentina; Ph. erythrinus Granara de Willink (Brasil y Argentina; Ph. peruvianus Granara de Willink (Argentina y Perú; Ph. sisymbriifolium Granara de Willink (Argentina y Uruguay; Ph. chilindrinae Granara de Willink, Ph. cornicirculus Granara de Willink, Ph. ruellia Granara de Willink, Ph. setosus Granara de Willink, Ph. sonoraensis Granara de Willink (México; Ph. hirsutus Granara de Willink (Puerto Rico; Ph. multicerarii Granara de Willink (Venezuela; Ph. sisalanus Granara de Willink (Haití y República Dominicana; Ph. toconaoensis Granara de Willink (Chile, y Ph. uruguayensis Granara de Willink (Uruguay. Todas las especies de Phenacoccus conocidas anteriormente para la región (24 en total son diagnosticadas. También se citan, ilustran y describen Phenacoccus artemisiae Ehrhorn y Ph. graminicola Leonardi, encontradas por primera vez en la Argentina. Se incluyen claves de géneros de Phenacoccinae neotropicales y de las especies de Phenacoccus neotropicales y también una lista de plantas hospederas de los Phenacoccus, que contiene 48 Familias Botánicas y 124 especies. Finalmente se realizó un análisis cladístico de los Phenacoccinae neotropicales, que incluye además de Phenacoccus los siguientes géneros: Brasiliputo Williams & Granara de Willink, Brevennia Goux, Chileputo Williams & Granara de Willink, Heliococcus Sulc, Heterococcus Ferris, Mammicoccus Balachowsky, Peliococcus Borchsenius, Pellizzaricoccus Kozár. Una matriz de 60 taxones (que incluye 10 géneros y 111 caracteres morfológicos, fue analizada mediante el criterio de parsimonia con el género Puto Signoret como taxón raíz. Los resultados