Seasonal pattern of seed dormancy in parthenium hysterophorus L

International Nuclear Information System (INIS)

Arshad Javaid, A.; Shafique, S.; Shafique, S.

2010-01-01

Earlier non-conclusive results have been reported on the initial dormancy status of parthenium (Parthenium hysterophorus L.) seeds. The present study reports the seasonal dormancy pattern of parthenium in Lahore, Pakistan where there are four distinct seasons viz. summer, autumn, winter and spring in a year. Mature parthenium seeds were collected on the last day of each month from January to December 2006 and investigations for their germination percentage and rate of germination were started on the next day. Parthenium seeds collected during coldest months of January and December showed highest germination of 100% with germination rate of 33.3% per day. Conversely, seeds collected in summer months of April to September exhibited lowest germination of 0-7% and germination rate of 0-1.75% per day. Seeds collected in rest of the months showed variable final germination percentage and germination rate ranging from 30-97% and 3.8-17.4%, respectively. Both the final germination and germination rate showed a highly significant negative correlation with the solar radiation and environmental temperature during the seed development period. The present study concludes that dormancy in parthenium seeds depends upon the temperature and solar radiation during the seed development period. (author)

Parthenium dermatitis severity score to assess clinical severity of disease

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Kaushal K Verma

2017-01-01

Full Text Available Background: Parthenium dermatitis is the most common type of airborne contact dermatitis in India. It is a chronic disease of a remitting and relapsing course with significant morbidity and distress, but there is no scoring system to assess its severity. Aim: To design a scoring system for the assessment of clinical severity of disease in Parthenium dermatitis and to use this scoring system in various studies to determine its sensitivity, specificity, and reproducibility. Methods and Results: In our first few studies on Parthenium dermatitis, we designed and used a basic clinical severity scoring system based on itching, morphology of the lesions, and areas involved. However, in subsequent studies, we modified it to the present scoring system as Parthenium dermatitis severity score (PDSS. Our studies showed the high sensitivity of PDSS in characterization of the disease severity at the given point of time, as well as to determine the efficacy of a prescribed treatment modality which was reliable and reproducible. Conclusion: Thus, PDSS may be used by clinicians for appropriate scoring of the clinical severity of Parthenium dermatitis and in monitoring the disease response to therapy.

Stimulation Versus Inhibition—Bioactivity of Parthenin, A Phytochemical From Parthenium hysterophorus L.

OpenAIRE

Belz, Regina G.

2007-01-01

Parthenium hysterophorus L. is an invasive weed that biosynthesizes several phytochemi-cals. The sesquiterpene lactone parthenin receives most attention regarding allelopathy of the plant or potential herbicidal properties. Since parthenin exhibits dose-dependent phy-totoxicity with low dose stimulation, this study investigated the occurrence and temporal features of parthenin hormesis in Sinapis arvensis L. sprayed with parthenin under semi-natural conditions. Dose/response studies showed th...

Bioassay-guided isolation of apigenin with GABA-benzodiazepine activity from Tanacetum parthenium

DEFF Research Database (Denmark)

Jäger, Anna Katharina; Krydsfeldt, Katrine; Rasmussen, Hasse Bonde

2009-01-01

Extracts of Tanacetum parthenium are used in the prophylactic treatment of migraine and have also been used in Danish folk medicine for the treatment of epilepsy. An ethanol extract of T. parthenium showed high affinity for the GABA(A)-benzodiazepine site. An ethanol extract of T. parthenium was ...

EFFICIENCY OF COMPOSTING PARTHENIUM PLANT AND NEEM LEAVES IN THE PRESENCE AND ABSENCE OF AN OLIGOCHAETE, EISENIA FETIDA

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S. Sivakumar ، H. Kasthuri ، P. Senthilkumar ، C. V. Subbhuraam ، Y. C. Song

2009-07-01

Full Text Available Parthenium plants and neem leaves were composted using the epigeic earthworm, Eisenia fetida (worm-worked compost to study the growth and reproductive indices of earthworm involved in the process of composting. Similarly, parthenium plants and neem leaves were composted without worms (worm-unworked compost. Efficacy of the resulting composts in supporting the growth of plant was tested with the germination and growth of Vigna radiate seedlings. The results showed that higher parthenium amendment significantly reduced the growth and reproduction of Eisenia fetida compared with control. The two-way ANOVA results showed a significant difference in the growth rate of worms when exposed to different amended concentrations of parthenium plants and neem leaves at different durations as fixed factors. The following compost parameters were not significantly different when compared with control: pH, nitrogen, phosphorus, iron for parthenium worm-worked compost; nitrogen, phosphorus, magnesium, iron, organic carbon and carbon/nitrogen ratio for neem worm-worked compost; nitrogen, phosphorus and organic carbon for parthenium worm-unworked compost and pH, nitrogen, phosphorus, zinc and carbon/nitrogen ratio for neem worm-unworked compost. Between parthenium plant composts and neem leaves composts, significant differences were not observed in any of the plant biometric parameters. The results obtained from the present study indicated that the parthenium composting at low amendments with cow dung may help its eradication for better utilization.

Diazotrophic diversity in the rhizosphere of two exotic weed plants, Prosopis juliflora and Parthenium hysterophorus.

Science.gov (United States)

Cibichakravarthy, B; Preetha, R; Sundaram, S P; Kumar, K; Balachandar, D

2012-02-01

This study is aimed at assessing culturable diazotrophic bacterial diversity in the rhizosphere of Prosopis juliflora and Parthenium hysterophorus, which grow profusely in nutritionally-poor soils and environmentally-stress conditions so as to identify some novel strains for bioinoculant technology. Diazotrophic isolates from Prosopis and Parthenium rhizosphere were characterized for nitrogenase activity by Acetylene Reduction Assay (ARA) and 16S rRNA gene sequencing. Further, the culture-independent quantitative PCR (qPCR) was performed to compare the abundance of diazotrophs in rhizosphere with bulk soils. The proportion of diazotrophs in total heterotrophs was higher in rhizosphere than bulk soils and 32 putative diazotrophs from rhizosphere of two plants were identified by nifH gene amplification. The ARA activity of the isolates ranged from 40 to 95 nmol ethylene h(-1) mg protein(-1). The 16S rRNA gene analysis identified the isolates to be members of alpha, beta and gamma Proteobacteria and firmicutes. The qPCR assay also confirmed that abundance of nif gene in rhizosphere of these two plants was 10-fold higher than bulk soil.

Atividade relativa da catalase de losna-branca (Parthenium hysterophorus comparada à de outras espécies daninhas Catalase relative activity of ragweed (Parthenium hysterophorus compared to that of other weed species

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S.J.P. Carvalho

2012-06-01

Full Text Available Este trabalho foi desenvolvido com o objetivo de avaliar a atividade relativa da catalase em extrato aquoso de losna-branca (Parthenium hysterophorus, bem como comparála à atividade da catalase de outras espécies daninhas. O trabalho constou de três fases, que envolveram a padronização do método, comparação da atividade relativa da catalase de plantas da família Asteraceae e comparação com outras 11 espécies daninhas, sendo estas: Euphorbia heterophylla, Alternanthera tenella, Cenchrus echinatus, Panicum maximum, Amaranthus viridis, Ipomoea hederifolia, Galinsoga parviflora, Bidens pilosa, Sonchus oleraceus, Cyperus rotundus e Commelina benghalensis. Observou-se resposta linear crescente da reação entre extrato aquoso de losna-branca e peróxido de hidrogênio, em razão da concentração do extrato vegetal. Em todas as fases, a atividade relativa da catalase de extrato de losna-branca foi superior à atividade da catalase das demais espécies daninhas. Com os dados obtidos nas três fases, conclui-se que a maior atividade relativa observada para a catalase da losnabranca contribui significativamente para a tolerância dessa espécie ao herbicida paraquat. Essa maior atividade pode ser consequência da maior concentração enzimática nas células ou devido à maior atividade intrínseca da enzima (afinidade enzima-substrato, havendo necessidade de estudos mais precisos para essa conclusão.This work was carried out to evaluate catalase relative activity of ragweed (Parthenium hysterophorus aqueous extract, as well as to compare it with catalase activity of other weed species. It consisted of three phases, involving method standardization, comparison of the catalase relative activity in Asteraceae family plants and that of ragweed catalase activity with the following 11 weed species: Euphorbia heterophylla, Alternanthera tenella, Cenchrus echinatus, Panicum maximum, Amaranthus viridis, Ipomoea hederifolia, Galinsoga parviflora

Pattern of cross-sensitivity between 4 Compositae plants, Parthenium hysterophorus, Xanthium strumarium, Helianthus annuus and Chrysanthemum coronarium, in Indian patients.

Science.gov (United States)

Nandakishore, T; Pasricha, J S

1994-03-01

To assess the pattern of cross-sensitivity between 4 members of the Compositae family, namely Parthenium hysterophorus L., Xanthium strumarium L., Helanthus annuus L. and Chrysanthemum coronarium L., 63 patients clinically diagnosed to have airborne contact dermatitis, and 51 controls having well-defined patterns of contact dermatitis caused by agents other than plants, were patch tested with measured amounts of standardized aqueous extracts of these plants. Positive reactions were obtained in 62 patients and 13 controls with Parthenium hysterophorus, in 47 patients and 9 controls with Xanthium strumarium, in 7 patients and 2 controls with Helianthus annuus, and in 13 of the 57 patients and one out of 28 controls tested with Chrysanthemum coronarium. 2 patients were allergic to all 4 of the plants; 14 patients to 3 plants, namely Parthenium, Xanthium and Chrysanthemum in 9 cases and Parthenium, Xanthium and Helianthus in 5 cases; 32 patients to 2 plants, namely Parthenium and Xanthium in 30 cases, and Parthenium and Chrysanthemum, and Xanthium and Chrysanthemum in 1 case each; 15 patients were allergic to 1 plant only, that being Parthenium. All the 47 patients allergic to Xanthium, 13 patients allergic to Chrysanthemum and 7 patients allergic to Helianthus were positive with some other plant as well. There was 1 patient who was allergic to Xanthium and Chrysanthemum but not to Parthenium. The titre of contact hypersensitivity (TCH) determined in the patients allergic to Parthenium, Xanthium and Helianthus showed values that varied widely with each plant in different patients, and there was no parallelism between the TCH with various plants.(ABSTRACT TRUNCATED AT 250 WORDS)

Air-borne contact dermatitis due to Chrysanthemum with true cross sensitivity to Parthenium hysterophorus and Xanthium strumarium

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Pasricha J

1992-01-01

Full Text Available A 60-year old man living in Srinagar (Jammu and Kashmir had air-borne contact dermatitis for last 10 years. He had never traveled to any other part of the country where Parthenium hysterophorus or Xanthium strumarium are prevalent but he used to cultivate chrysanthemums. Patch tests with standardized extracts of various plants revealed the strongest reaction with Chrysanthemum, while the reactions with Xanthium strumarium and Parthenium hysterophorus were also positive but milder. This seems to be a case of primary sensitivity to Chrysanthemum with cross sensitivity to Xanthium strumarium and Parthenium hysterophorus.

Tanacetum parthenium leaf extract mediated survival protection in lethally irradiated Swiss albino mice

International Nuclear Information System (INIS)

Shetty, Prashanth; Pooja, S.; Suchetha Kumari, N.; Shetty, Jayaram; Peter, Alex John; Jose, Jerish M.

2016-01-01

Search for less-toxic radioprotectors has spurred interest in the development of natural products. In Ayurveda, the traditional medicine, Tanacetum species have been used to treat ailments since ancient times throughout the world. Effects of the administration of different concentrations of Tanacetum parthenium leaf aqueous extract (TPLA), Tanacetum parthenium leaf ethanolic extract (TPLE) were investigated in Swiss albino mice. Mice (20-25 g) were randomly divided into 8 groups of ten animals each. The control group and the radiation group were treated daily with oral administration of saline for 15 days. Each subgroups of TPLA and TPLE were treated with doses of 50, 100 and 250 mg/kg daily for 15 days. On the 15th day, all were irradiated with 10 Gy whole body irradiation. Survival was observed daily up to 30th post-irradiation day. Data were analysed using the Kaplan-Meier survival curves. The significance difference in survival between control, radiation and treatment groups were observed (P < 0.001). Current studies revealed the protective effect of Tanacetum parthenium rendering high survivability in lethally irradiated mice. (author)

Genomic diversity and phylogenetic relationships in the genus Parthenium (Asteraceae)

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Guayule (Parthenium argentatum A. Gray) is a perennial hardwood shrub native to the North American Chihuahuan Desert that holds promise as a sustainable source of natural rubber and hypoallergenic latex. The improvement of guayule for commercial-scale production could be potentially accelerated thro...

Stimulation versus inhibition--bioactivity of parthenin, a phytochemical from Parthenium hysterophorus L.

Science.gov (United States)

Belz, Regina G

2007-09-30

Parthenium hysterophorus L. is an invasive weed that biosynthesizes several phytochemicals. The sesquiterpene lactone parthenin receives most attention regarding allelopathy of the plant or potential herbicidal properties. Since parthenin exhibits dose-dependent phytotoxicity with low dose stimulation, this study investigated the occurrence and temporal features of parthenin hormesis in Sinapis arvensis L. sprayed with parthenin under semi-natural conditions. Dose/response studies showed that the occurrence and the magnitude of hormesis depended on climatic conditions and the parameter measured. Within the tested dose range, stimulatory responses were only observed under less-stressful conditions and were most pronounced for leaf area growth [138 % of control; 13 days after treatment (DAT)]. Temporal assessment of leaf area development showed that doses causing a stimulatory response at the end of the experiment (allelopathy of P. hysterophorus and exploitation of growth stimulatory responses in agriculture.

Screening and optimization of pretreatments for Parthenium hysterophorus as feedstock for alcoholic biofuels

International Nuclear Information System (INIS)

Singh, Shuchi; Khanna, Swati; Moholkar, Vijayanand S.; Goyal, Arun

2014-01-01

Highlights: • Optimization of pretreatment methods for Parthenium hysterophorus for bioalcohol production. • Physical, chemical and physicochemical pretreatments methods employed. • Most efficient treatment: autoclaving 121 °C, 15 psi for 30 min in 1% H 2 SO 4 solution. • TFS (total fermentable sugar) yield after pretreatment and enzymatic hydrolysis = 397.7 mg/g raw biomass. • Parthenium hysterophorus is at par with agro- and forest residues as biofuels feedstock. - Abstract: Parthenium hysterophorus world’s seven most devastating and hazardous weeds, and is abundantly available in several parts of the world. This study treats the subject of effective utilization of this waste biomass (which has cellulose content of 45.2 ± 1.81% w/w) for biofuels production. We have presented a comprehensive and comparative assessment of numerous pretreatment strategies for P. hysterophorus, comprising of all major physical, chemical and physicochemical methods. The yardstick of assessment has been amount of fermentable sugars released during the pretreatment and the post-treatment enzymatic hydrolysis of pretreated biomass. Carboxymethylcellulase (1.0 U/mg, 1.7 mg/mL) produced by an isolate Bacillus amyloliquefaciens SS35 and β-glucosidase (Novozyme 188), have been used for enzymatic hydrolysis of pretreated biomass. Among the different methods employed for pretreatment, the most efficient treatment has been revealed to be autoclaving of biomass at 121 °C and 15 psi pressure for 30 min in acidic (1% v/v, H 2 SO 4 ) environment. Total reducing sugar (TRS) yield during this pretreatment, mainly due to hydrolysis of hemicellulosic fraction of biomass, has been 285.3 mg/g of raw biomass. Further enzymatic hydrolysis resulted in reducing sugar yield of 187.4 mg/g of pretreated biomass (9.37 g/L). The total fermentable sugar (TFS) yield from the optimized pretreatment was 397.7 mg/g raw biomass (39.77 g/100 g raw biomass). The effects of different pretreatment methods

Determination of Kinetic Parameters for the Thermal Decomposition of Parthenium hysterophorus

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Dhaundiyal Alok

2018-02-01

Full Text Available A kinetic study of pyrolysis process of Parthenium hysterophorous is carried out by using thermogravimetric analysis (TGA equipment. The present study investigates the thermal degradation and determination of the kinetic parameters such as activation E and the frequency factor A using model-free methods given by Flynn Wall and Ozawa (FWO, Kissinger-Akahira-Sonuse (KAS and Kissinger, and model-fitting (Coats Redfern. The results derived from thermal decomposition process demarcate decomposition of Parthenium hysterophorous among the three main stages, such as dehydration, active and passive pyrolysis. It is shown through DTG thermograms that the increase in the heating rate caused temperature peaks at maximum weight loss rate to shift towards higher temperature regime. The results are compared with Coats Redfern (Integral method and experimental results have shown that values of kinetic parameters obtained from model-free methods are in good agreement. Whereas the results obtained through Coats Redfern model at different heating rates are not promising, however, the diffusion models provided the good fitting with the experimental data.

Nature's Migraine Treatment: Isolation and Structure Elucidation of Parthenolide from "Tanacetum parthenium"

Science.gov (United States)

Walsh, Emma L.; Ashe, Siobhan; Walsh, John J.

2012-01-01

The purpose of this experiment is to provide students with the essential skills and knowledge required to perform the extraction, isolation, and structural elucidation of parthenolide from "Tanacetum parthenium" or feverfew. Students are introduced to a background of the traditional medicinal uses of parthenolide, while more modern applications of…

Weed seed spread and its prevention: The role of roadside wash down.

Science.gov (United States)

Bajwa, Ali Ahsan; Nguyen, Thi; Navie, Sheldon; O'Donnell, Chris; Adkins, Steve

2018-02-15

Vehicles are one of the major vectors of long-distance weed seed spread. Viable seed removed from vehicles at roadside wash down facilities was studied at five locations in central Queensland, Australia over a 3-year period. Seed from 145 plant species, belonging to 34 different families, were identified in the sludge samples obtained from the wet particulate matter collection pit of the wash down facilities. Most of the species were annual forbs (50%) with small or very small seed size (weed was observed in these samples. More parthenium weed seed were found in the Rolleston facility and in the spring, but its seed was present in all facilities and in all seasons. The average number of viable seed found within every ton of dry particulate matter removed from vehicles was ca. 68,000. Thus, a typical wash down facility was removing up to ca. 335,000 viable seed from vehicles per week, of which ca. 6700 were parthenium weed seed. Furthermore, 61% of these seed (ca. 200,000) were from introduced species, and about half of these (35% of total) were from species considered to be weeds. Therefore, the roadside wash down facilities found throughout Queensland can remove a substantial amount of viable weed seed from vehicles, including the invasive parthenium weed, and the use of such facilities should be strongly encouraged. Copyright © 2017 Elsevier Ltd. All rights reserved.

Preliminary investigation on the natural durability of guayule (Parthenium argentatum) based wood products

Science.gov (United States)

Francis S. Nakayama; Poo. Chow; Dilpreet S. Bajwa; John A. Youngquist; James H. Muehl; Andrzej M. Krzysik

2000-01-01

Conventional preservatives used to protect wood from insect and microbial damages are presently of major concern to human health and the environment. Finding alternative and economical preservatives has not been successful. Previous studies have shown that the resinous material extracted from the guayule plant (Parthenium argentatum, Gray) has both insect- and...

Weekly azathioprine pulse versus daily azathioprine in the treatment of Parthenium dermatitis: A non-inferiority randomized controlled study

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Kaushal K Verma

2015-01-01

Full Text Available Background: Azathioprine in daily doses has been shown to be effective and safe in the treatment of Parthenium dermatitis. Weekly pulses of azathioprine (WAP are also effective, but there are no reports comparing the effectiveness and safety of these two regimens in this condition. Aims: To study the efficacy and safety of WAP and daily azathioprine in Parthenium dermatitis. Methods: Sixty patients with Parthenium dermatitis were randomly assigned to treatment with azathioprine 300 mg weekly pulse or azathioprine 100 mg daily for 6 months. Patients were evaluated every month to assess the response to treatment and side effects. Results: The study included 32 patients in the weekly azathioprine group and 28 in the daily azathioprine group, of whom 25 and 22 patients respectively completed the study. Twenty-three (92% patients on WAP and 21 (96% on daily azathioprine had a good or excellent response. The mean pretreatment clinical severity score decreased from 26.4 ± 14.5 to 4.7 ± 5.1 in the WAP group, and from 36.1 ± 18.1 to 5.7 ± 6.0 in the daily azathioprine group, which was statistically significant and comparable (P = 0.366. Patients on WAP had a higher incidence of adverse effects (P = 0.02. Limitations: The study had a small sample size and the amount of clobetasol propionate used in each patient was not determined, though it may not have affected the study outcome due to its comparable use in both groups. Conclusions: Azathioprine 300 mg weekly pulse and 100 mg daily dose are equally effective and safe in the treatment of Parthenium dermatitis.

Magnesium affects rubber biosynthesis and particle stability in Ficus elastica, Hevea brasiliensis and Parthenium argentatum

Science.gov (United States)

Natural rubber biosynthesis occurs in laticifers of Ficus elastica and Hevea brasiliensis, and in parenchyma cells of Parthenium argentatum. Natural rubber is synthesized by rubber transferase using allylic pyrophosphates as initiators, isopentenyl pyrophosphate as monomeric substrate and magnesium ...

Optical parameters of leaves of seven weed species

Science.gov (United States)

Gausman, H. W.; Menges, R. M.; Richardson, A. J.; Walter, H.; Rodriguez, R. R.; Tamez, S. (Principal Investigator)

1982-01-01

The absorption coefficient (k), infinite reflectance (R), and scattering coefficient (s) were tabulated for five wavelengths and analyzed for statistical differences for seven weed species. The wavelengths were: 0.55-micrometer, 0.65-micrometers, 0.85-micrometer, 1.65-micrometers, and 2.20-micrometer. The R of common lambsquarters (Chenopodium album L.), Johnsongrass (Sorghum halepense (L.) Pers.), and annual sowthistle (Sonchus oleraceus L.) leaves at the 0.85-micrometer wavelength were significantly (p=0.05) higher than for sunflower (Heliantus annus L.), ragweed parthenium (Parthenium hysterophorus L.), or London rocket (Sisymbrium irio L.). Annual sowthistle had the largest k value, and Plamer amaranth (Amaranthus palmer S. Wats.) had the smallest k value at the 0.65 approximately chlorophyll absorption wavelength. In general, john-songress, ragweed parthenium, or London rocket had the largest s values among the five wavelengths, wereas annual sowthistle and plamar amaranth were usually lowest.

The content of parthenolide and its yield per plant during the growth of Tanacetum parthenium

NARCIS (Netherlands)

Hendriks, H; Anderson-Wildeboer, Y.; Bos, R.; Woerdenbag, H.J.

During the growth of Tanaceum parthenium (L.) Schultz-Bip. Feverfew, Asteraceae) the percentage of parthenolide was the highest at an early stage (just before the formation of stems), The yield of parthenolide per individual plant gradually increased from about 10 mg at the beginning of the study to

Do monoterpenes released from feverfew (Tanacetum parthenium) plants cause airborne Compositae dermatitis?

DEFF Research Database (Denmark)

Paulsen, E.; Christensen, Lars Porskjær; Andersen, K.E.

2002-01-01

The Compositae plant feverfew (Tanacetum parthenium) is an important sensitizer in Europe and has been suspected of causing airborne Compositae dermatitis. A previous investigation of substances emitted from feverfew plants detected no sesquiterpene lactones, however, but mainly monoterpenes...... airborne dermatitis, mimicking photosensitivity, and the disappearance of symptoms upon removal of feverfew plants suggest monoterpenes as a possible contributing factor. Similar associations between doubtful positive monoterpene reactions and clinical patterns, fragrance/colophonium allergy and relevance...

Fast determination of the resin and rubber content in Parthenium argentatum biomass using near infrared spectroscopy

NARCIS (Netherlands)

Suchat, S.; Pioch, D.; Palu, S.; Tardan, E.; Loo, van E.N.; Davrieux, F.

2013-01-01

Guayule (Parthenium argentatum), a plant native of semi-arid regions of northern Mexico and southern Texas, United States, is an under-used source of hypoallergenic latex, a solution to the serious latex allergy IgE problem worldwide. This study aimed to develop near infrared spectroscopy (NIRS)

The Insecticidal Activity of Tanacetum parthenium (L.) Schultz Bip. Extracts Obtained by Supercritical Fluid Extraction and Hydrodistillation

Czech Academy of Sciences Publication Activity Database

Pavela, R.; Sajfrtová, Marie; Sovová, Helena; Bárnet, M.; Karban, Jindřich

2010-01-01

Roč. 31, č. 3 (2010), s. 449-454 ISSN 0926-6690 R&D Projects: GA MŠk 2B06049 Institutional research plan: CEZ:AV0Z40720504 Keywords : botanical insecticides * spodoptera littoralis * tanacetum parthenium Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 2.507, year: 2010

Evaluation of the larvicidal efficiency of stem, roots and leaves of the weed, Parthenium hysterophorus (Family: Asteraceae against Aedes aegypti L.

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Sarita Kumar

2012-10-01

Full Text Available Objective: To assess the larvicidal potential of various extracts prepared from the stem, roots and leaves of Parthenium hysterophorus (P. hysterophorus against 3rd and 4th instars of Aedes aegypti (Ae. aegypti. Methods: The extracts from each part were prepared with four solvents; petroleum ether, hexane, acetone and diethyl ether. Each part was dried, powdered and soaked in different solvents, separately, for five days. The crude extracts thus formed were concentrated using rotary evaporator and stored as stock solution of 1 000 mg/L. Results: All the extracts prepared from the leaves were found ineffective against both the instars causing only 10%-40% mortality. Against 3rd instars, the hexane and petroleum ether extracts prepared from the stem of P. hysterophorus were found effective exhibiting LC50 values of 379.76 and 438.57 mg/L, respectively. Likewise the hexane and petroleum ether extracts from the Parthenium roots resulted in LC50 values of 432.38 and 562.50 mg/L, respectively, against 4th instars of Ae. aegypti revealing their larvicidal potential. It was further found that the hexane extracts, whether from roots or stem, were 13-28% more effective than the petroleum ether extracts. The qualitative phytochemical study of the effective extracts from the stems and roots showed the presence of alkaloids, saponins, terpenoids and flavonoids in different combinations. Conclusions: Our investigations demonstrated the potential of P. hysterophorus roots and stems against Ae. aegypti larvae and their benefits as new types of mosquito larvicides. Variety of types and levels of active constituents in each kind of extract may be responsible for the variability in their potential against Ae. aegypti. Further research is needed to identify these components.

Bio-synthesis and antimicrobial activity of silver nanoparticles using anaerobically digested parthenium slurry.

Science.gov (United States)

Adur, Alaknanda J; Nandini, N; Shilpashree Mayachar, K; Ramya, R; Srinatha, N

2018-06-01

Silver nanoparticles were prepared through eco-friendly, cost effective, bio-mediated technique using anaerobically digested Parthenium hysterophorous digested slurry (PDS) for the first time. The synthesized nanoparticles were characterized through different techniques such as UV-Vis spectrophotometer for optical properties; X-ray diffractometer (XRD), high resolution transmission electron spectroscopy (HR-TEM) and Fourier Transform Infra Red (FTIR) Spectroscopy for structural property investigations. It was observed that the prepared silver nanoparticles were crystallized in face centered cubic crystal structure with an average particle size of 19 nm as confirmed from XRD. Also HR-TEM studies reveal the formation of nano-sized silver particles with face centered cubic nano structure. In addition, absorption spectra exhibit Surface Plasmon Resonance (SPR) which suggests the formation of silver nanoparticles. FTIR results show the presence of different characteristic functional groups and their stretching / bending vibrations in turn responsible for the bioreduction of silver ions in Parthenium digested slurry. Further investigations on antimicrobial activity were done by subjecting the synthesized silver nanoparticles on E-coli and Pseudomonas as marker organisms for the group of gram negative bacteria by well plate method on enrichment media. The result obtained shows a clear zone of inhibition confirming the antibacterial activity. Overall, the investigated results confirm the biosynthesized silver nanoparticles are potential candidates for antimicrobial activity applications. Copyright © 2018 Elsevier B.V. All rights reserved.

Hepatoprotective effect of methanolic Tanacetum parthenium extract on CCl4-induced liver damage in rats

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Yavar Mahmoodzadeh

Full Text Available The purpose of this study was to investigate the effects of Tanacetum Parthenium Extract (TPE on Lipid peroxidation, antioxidant enzymes, biochemical factors, and liver enzymes in the rats damaged by Carbon Tetrachloride (CCl4.54 male Wistar rats were divided into 9 groups each consisting of 6 rats. Two of the groups were control groups (normal and damage control groups, 4 of them were exposure groups which were respectively administered with 40, 80, and 120 mg/kg of TPE and silymarin for 14 days before being damaged by CCl4, and the other 3 groups were post-treatment groups which received 80 and 120 mg/kg of TPE and silymarin 2, 6, 24, and 48 h after being injected with CCl4. At the end of the study, biochemical factors, serum liver enzymes, malondialdehyde level, antioxidant enzymes, and liver morphology were assayed.Pre- and post-treatment with TPE could significantly decrease ALT, AST, ALP, TG, LDL, TC, and glucose levels and increase HDL, and albumin levels and catalase, SOD, and GPx activities compared to the CCl4-damaged control group.The results of this study are indicative of the antioxidant activity of TPE, its potential hepatoprotective effects, and its probable therapeutic properties for laboratory animals damaged by CCl4. Keywords: Tanacetum parthenium, Carbon tetrachloride, Oxidative stress, Antioxidant enzymes, Liver damage

Soil degradation of parthenin-does it contradict the role of allelopathy in the invasive weed Parthenium hysterophorus L.?

Science.gov (United States)

Belz, Regina G; van der Laan, Michael; Reinhardt, Carl F; Hurle, Karl

2009-09-01

The invasive success of Parthenium hysterophorus L. is thought to be partially attributable to allelopathy mediated by the plant metabolite parthenin. To assess the ecological significance of parthenin release from plant material, its persistence and phytotoxicity in soil was studied. Results show parthenin is rapidly degraded with an average DT (50) of 59 h under standard experimental conditions. Degradation was delayed in sterilized soils, at lower soil moisture, and higher parthenin concentrations. Higher temperatures, higher CEC(pot)/clay content of soils, soil preconditioning with parthenin, and P. hysterophorus infestation accelerated degradation. Physico-chemical and biological processes are, therefore, expected to govern the fate of parthenin in soil. Parthenin exhibited low soil phytotoxicity and did not accumulate over time. Along with the indicated reduction in bioavailability and development of hormetic effects, results suggest that for parthenin to have detrimental allelopathic effects, it requires high P. hysterophorus densities that result in high soil levels of parthenin and soil conditions that favor the persistence of parthenin. In light of this, the ecological significance of parthenin is discussed.

Competitive Exclusion of Parthenium hysterophorus by Other Invasive Species - A Case Study from Andhra Pradesh, India

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J. Asha kumari

2010-06-01

Full Text Available The abundance, dominance and growth performance of Parthenium hysterophorus in relation to its field associates in extensively large areas was investigated. The preliminary analysis of the data revealed that P. hysterophorus is a weak or poor competitor and hence it fails to grow in the company of any aggressive species. Senna uniflora and a few other plants were identified for the control of this pernicious weed. The ability of other species to control P. hysterophorus was attributed to allelopathy. In order to understand how Hyptis suaveolens and Senna uniflora are capable of arresting the growth of P. hysterophorus, pot culture experiments in de Wit replacement series, field experiments in experimental plots and experimental manipulation of the competitive species under natural conditions during different seasons were carried out for two years in 2004 and 2005. The results clearly revealed that both H. suaveolens and S. uniflora were highly effective in the management of P. hysterophorus. The results further showed that the physical dominance and the ability of the competitive species to deprive P. hysterophorus of light are mainly responsible for the decline of P. hysterophorus. Allelopathy doesn't seem to play any effective role under natural conditions.

Assessment of Caesium -137 accumulation from soil to autochthonous weeds

International Nuclear Information System (INIS)

Sreenivasa Chari, M.; Karuna Sagar, G.; Manjaiah, K.M.

2017-01-01

A study was conducted at Nuclear Research Laboratory (NRL), IARI, New Delhi to obtain radio cesium ( 137 Cs) Soil-to-plant transfer factors of autochthonous weeds at low level of contamination, where contamination is a legacy of experimental activities. Studied area is sporadically covered with autochthonous weeds mainly with Amaranthus viridis, Cynodon dactylon, Cassia auriculata, Brachiaria mutica, Parthenium hysterophorus, Bohervia diffusa and some taxonomically unidentified weeds. Extractability as well as bioavailability of 137 Cs was quantified by sequential extraction. In the representative plant and soil samples, 137 Cs activity was measured directly with the 2.5” × 2.5” NaI (TI) well type detector installed in 15 cm thick lead shield and single channel gamma analyzer. Transfer factors of grassy weeds were 0.143 to 0.310 (1.43 × 10 -2 to 3.1 × 10 -2 ), for broad leaved weeds 0.103 to 0.133 (1.03 × 10 -2 to 1.33 × 10 -2 ). Increase in the activity levels increased the transfer factors of weeds. Irrespective of activity levels higher transfer factors were observed in roots ranging from 0.13 to 0.28 (1. 3 × 10 -1 to 2.8 × 10 -1 ). At both the levels (40 and 80 µci) Cynodon dactylon recorded higher root and shoot transfer factor of 2.99 and 0.29 respectively, when compared to other weeds. Significantly lower transfer factors were observed in Parthenium hysterophorus. Geochemical partitioning shown that the reducible phase (56%) is the largest sink for 137 Cs in the studied soils

Development of enteric coated tablets from spray dried extract of feverfew (Tanacetum parthenium L:

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Juliana Siqueira Chaves

2009-09-01

Full Text Available Tanacetum parthenium (feverfew is an herb that is commercialized worldwide as a therapeutic treatment for migraine. Its pharmacological effect is mainly due to the presence of the sesquiterpene lactone parthenolide as well as of flavonoids. So far, there are no studies on standardization of pre-formulations or phytomedicines containing this herb. The present study aimed at developing a pre-formulation using a standardized spray-dried extract of feverfew and further designing and standardizing enteric coated tablets. In this work, the spray-dried extract of feverfew was evaluated for its parthenolide, santin and total flavonoid content, parthenolide solubility, particle size, tapped density, hygroscopicity, angle of repose and moisture content. Tablets containing the spray-dried extract were tested for their average weight, friability, hardness, and disintegration time. The total flavonoid and parthenolide contents in the spray-dried extract were 1.31 % and 0.76% w/w, respectively. The spray-dried extract presented consistent pharmacotechnical properties and allowed its tableting by direct compression. Tablet properties were in accordance with the proposed specifications. The procedures described herein can be used to prepare and evaluate pre-formulations of feverfew with adequate properties for the development of a high-quality phytomedicine.Tanacetum parthenium (tanaceto é uma planta medicinal comercializada no mundo todo para tratamento de enxaqueca. Seu efeito farmacológico é creditado principalmente à lactona sesquiterpênica partenolídeo e flavonóides. Até o momento não existem estudos sobre a padronização de pré-formulações ou o desenvolvimento de fitoterápicos com tanaceto. Logo, o objetivo deste trabalho foi obter comprimidos de revestimento entérico a partir de extrato seco e padronizado de tanaceto. Neste trabalho, o extrato seco do tanaceto obtido pelo método de spray drying foi avaliado quanto ao teor de partenol

Antibacterial activity and the variation of Tanacetum parthenium (L.) Schultz Bip. essential oils from Turkey.

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Polatoglu, Kaan; Demirci, Fatih; Demirci, Betül; Gören, Nezhun; Başer, Kemal Hüsnü Can

2010-01-01

Water-distilled essential oils from herbal parts of Tanacetum parthenium from two different localities in Turkey were analyzed by GC and GC/MS. The essential oil of T. parthenium collected from Davutpasa-Istanbul location were characterized with camphor 49%, trans-chrysanthenyl acetate 22.1% and camphene 9.4%. Second plant sample is collected from the remote east end of the country Savşat-Ardahan location. The essential oil from this location was characterized with camphor 60.8% and camphene 6.8%. Unlike the former this sample contains trans-chrysanthenyl acetate in trace amount and cis- chrysanthenyl acetate in very small amount (0.6%) which is not present in the first sample. Antibacterial activity of the oils were evaluated for five Gram (+) and five Gram (-) bacteria by using a broth microdilution assay. The highest activity was observed on Bacillus subtilis, Staphylococcus aureus and methicillin-resistant S.aureus however when compared with positive control oils showed higher MIC values. The oil of Istanbul-sample showed highest activity on B. subtilis (125 microg/mL) and methicillin-resistant S. aureus (125 microg/mL) which is two fold concentration when compared with the positive control chloramphenicol (62.5 microg/mL). The oil of Ardahan sample showed the highest activity on S. aureus (125 microg/mL) which is likewise two fold concentration of the positive control chloramphenicol (62.5 microg/mL). DPPH scavenging activity was 59.3% of the oil from Davutpasa at 15 mg/mL concentration. When compared to positive control alpha-tocopherol (94.6%) Savşat oil (28.2%) showed low and Davutpasa oil showed medium DPPH scavenging activity. All of the oils showed toxicity to Vibrio fischeri in the TLC-bioluminescence assay.

Evaluation of biomass of some invasive weed species as substrate for oyster mushroom (Pleurotus spp.) cultivation.

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Mintesnot, Birara; Ayalew, Amare; Kebede, Ameha

2014-01-15

This study assessed the bioconversion of Agriculture wastes like invasive weeds species (Lantana camara, Prosopis juliflora, Parthenium hysterophorus) as a substrate for oyster mushroom (Pleurotus species) cultivation together with wheat straw as a control. The experiment was laid out in factorial combination of substrates and three edible oyster mushroom species in a Completely Randomized Design (CRD) with three replications. Pleurotus ostreatus gave significantly (p mushroom cultivation could contribute to alleviating ecological impact of invasive weed species while offering practical option to mitigating hunger and malnutrition in areas where the invasive weeds became dominant.

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Items 51 - 100 of 106 ... Vol 24, No 1 (2013), Growth and yield components of tomato as influenced by nitrogen and phosphorus fertilizer applications in different growing seasons ... Vol 21, No 1-2 (2011), Parthenium Weed (Parthenium hysterophorus L.) Research in Ethiopia: Impacts on Food Production, Plant Biodiversity and ...

Specificity of HPLC to assess the chemical stability based on partenine from Parthenium hysterophorus L. powdered dry foliage (escoba amarga)

International Nuclear Information System (INIS)

Saucedo Hernandez, Yanelis; Mohamad Safa, Bassam; Gonzalez Bedia, Mirtha Mayra

2010-01-01

It is required a specific analysis technique allowing the follow-up to stability study intrinsic of Parthenium hysterophorus L. (escoba amarga) powdered dry foliage to achieve in a pharmaceutical way a antiparasitic usefulness with the quality, safety and effectiveness demanded requirements. High performance liquid chromatography was applied to P. hysterophorus degraded samples under degradation conditions in an oxidative, basic and acid medium. The analysis technique specificity was assessed to detect the interest component without interferences of its degradation products and its possible usefulness in studies on solid stability in the plant powder

Vermicomposting and anaerobic digestion – viable alternative options for terrestrial weed management – A review

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Biswanath Saha

2018-03-01

Full Text Available The management of terrestrial weed is of great concern for the scientific community as these weeds cause adverse effect in different ecosystems like forest, agriculture and urban. The widespread of these weeds by their adaptive capability and morphological advancement is difficult to control. Parthenium hysterophorous, Lantana camara, Saccharum spontaneum, Ageratum conyzoides are the weeds that spread all over the world. There are various management practices employed for the control of this weeds. But all of these practices have some drawbacks those are neither environment friendly nor economical. In this paper a review has been done to evaluate various alternative management practices for these terrestrial weeds and to analyze their feasibility. Vermicomposting and anaerobic digestion can be viable alternative option which is cost effective as well. There are few studies regarding vermicomposting and anaerobic digestions of terrestrial weeds are done.

Electron microscopy of hydrocarbon production in parthenium argentatum (guayule)

Energy Technology Data Exchange (ETDEWEB)

Bauer, Thomas E. [Univ. of California, Berkeley, CA (United States)

1977-11-01

The electron microscope was used to study the biological processes involved in hydrocarbon production. The little desert shrub Guayule (Parthenium argentatum) was selected for study. This shrub can produce hydrocarbons (rubber) in concentrations up to 1/4 of its dry weight. It grows on semi-arid land and has been extensively studied. The potential of Guayule is described in detail. Results of an investigation into the morphology of Guayule at the electron microscope level are given. Experiments, which would allow the biosynthesis of hydrocarbon in Guayule to be followed, were designed. In order to do this, knowledge of the biochemistry of rubber formation was used to select a tracer, mevalonic acid. Mevalonic acid is the precursor of all the terpenoids, a large class of hydrocarbons which includes rubber. It was found that when high enough concentrations of mevalonic acid are administered to seedling Guayule plants, build-ups of metabolized products are found within the chloroplasts of the seedlings. Also, tritium labeled mevalonic acid was used as a precursor, and its metabolic progress was followed by using the technique of electron microscope autoradiography. The results of these experiments also implicated chloroplasts of the Guayule plant in hydrocarbon production. The final task was the development of a system to produce three-dimensional stereo reconstructions of organelles suspected of involvement in hydrocarbon biosynthesis in Guayule. The techniques are designed to reconstruct an object from serial sections of that object. The techniques use stereo imaging both to abstract information for computer processing, and also in the computer produced reconstruction.

Weed management: a case study from north-west Pakistan

International Nuclear Information System (INIS)

Marwat, K.B.; Hashim, S.; Ali, H.

2010-01-01

Alien and exotic plant invasions are threatening the floral diversity around the globe and affect ecological processes. Weed invasion has been documented in North-West Pakistan. A total of 16 weeds were reported as invasive. These were Xanthium strumarium, Ipomoea eriocarpa, Alternanthera pungens, Trianthema portulacastrum, Tagetes minuta, Imperata cylindrica, Amaranthus hybridus subsp. hybridus, Robinia pseudo-acacia, Broussonetia papyrifera, Ailanthus altissima, Pistia stratiotes, Phragmites australis, Parthenium hysterophorus, Cannabis sativa, Galium aparine and Emex spinosus. Among these Robinia pseudo-acacia, Broussonetia papyrifera and Ailanthus altissima are trees and were purposely introduced as they later became invasive. They were aggressive in nature and replaced or suppressed the local vegetation. Their distribution, history of invasion and management has been discussed here. The behaviour and association of the 36 problem weeds with different crops has also been outlined as they perspired from the farmers. (author)

Weed management: a case study from north-west Pakistan

Energy Technology Data Exchange (ETDEWEB)

Marwat, K B; Hashim, S; Ali, H [KPK Agriculture University, Peshawar (Pakistan). Dept. of Weed Science

2010-12-15

Alien and exotic plant invasions are threatening the floral diversity around the globe and affect ecological processes. Weed invasion has been documented in North-West Pakistan. A total of 16 weeds were reported as invasive. These were Xanthium strumarium, Ipomoea eriocarpa, Alternanthera pungens, Trianthema portulacastrum, Tagetes minuta, Imperata cylindrica, Amaranthus hybridus subsp. hybridus, Robinia pseudo-acacia, Broussonetia papyrifera, Ailanthus altissima, Pistia stratiotes, Phragmites australis, Parthenium hysterophorus, Cannabis sativa, Galium aparine and Emex spinosus. Among these Robinia pseudo-acacia, Broussonetia papyrifera and Ailanthus altissima are trees and were purposely introduced as they later became invasive. They were aggressive in nature and replaced or suppressed the local vegetation. Their distribution, history of invasion and management has been discussed here. The behaviour and association of the 36 problem weeds with different crops has also been outlined as they perspired from the farmers. (author)

Reduced herbicide doses in combination with allelopathic plant extracts suppress weeds in wheat

International Nuclear Information System (INIS)

Afridi, R.A.; Khan, M.A.

2014-01-01

Allelopathy is gaining popularity worldwide probably for decreasing the cost of production and environment friendly weed suppressing approach. Repeated field studies conducted during 2011-12 and 2012-13 at Agricutural Research Institute Tarnab, Peshawar, Pakistan where allelopathic water extracts of Oryza sativa, Parthenium hysterophorus, Phragmites australis and Datura alba along with reduced doses of phenoxaprop-p-ethyl and bromoxinil+MCPA were tested for controlling weeds in wheat. It was observed that weed density was encouragly suppressed whereas spike length (cm), number of spikelets spike-1 and 1000 grain weight (g) of the wheat were improved when the allelopathic plant water extracts were used in combination with lower doses of herbicides. Thus, allelochemicals provide weed suppressing option in wheat. However, more studies are required to fully explore the possibility of weed management and isolation of the chemicals involved in weed suppression for environment friendly weed management in wheat. Such studies may decrease the cost of crop production and total use of herbicides. (author)

Plantas cultivadas e invasoras como habitat para predadores do gênero Orius(Wolff (Heteroptera: anthocoridae Crops and weeds as host plants Orius species (Heteroptera: anthocoridae

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Luís Cláudio Paterno Silveira

2003-01-01

Full Text Available O objetivo deste trabalho foi registrar as espécies de Orius associadas a plantas cultivadas e invasoras presentes em uma localidade de Minas Gerais e três de São Paulo, nos anos de 1999 e 2000. As coletas foram realizadas através de batidas das plantas no interior de sacos plásticos para desalojar os insetos. Posteriormente, as espécies foram separadas em laboratório. O predador Orius insidiosus (Say foi coletado nas culturas de milho (Zea mays L., milheto (Pennisetum glaucum (L. R.Br., sorgo (Sorghum spp., feijão (Phaseolus vulgaris L., girassol (Helianthus annuus L., alfafa (Medicago sativa L., soja [Glycine max (L. Merr.], crisântemo (Chrysanthemum spp., tango (Solidago canadensis L. e cartamus (Carthamus tinctorius L. e nas plantas invasoras picão-preto (Bidens pilosa L., caruru (Amaranthus sp., losna-branca (Parthenium hysterophorus L. e apaga-fogo (Alternanthera ficoidea L.. Orius thyestes Herring foi encontrado nas plantas invasoras picão-preto, caruru e apaga-fogo. Orius perpunctatus (Reuter e Orius sp. foram coletados principalmente nas plantas invasoras picão-preto, caruru e apaga-fogo e no milho. Constatou-se que muitas dessas plantas são reservatórios naturais para esses predadores, em termos de habitat, abrigo, presas e pólen.The aim of this research was to record the Orius species present on some crops and weeds in areas located in the southeast region in Brazil, during 1999 and 2000. The insect collections were made through the tapping method to dislodge the insects from the plant into a plastic bag. The identifications of the specimens was done in the laboratory. Orius insidiosus (Say was collected on the following crops: corn (Zea mays L., pearl millet (Pennisetum glaucum (L. R.Br., sorghum (Sorghum spp., bean (Phaseolus vulgaris L., sunflower (Helianthus annuus L., alfalfa (Medicago sativa L., soybean (Glycine max (L. Merr., chrysanthemum (Chrysanthemum spp., tango (Solidago canadensis L. and carthamus

Antimicrobial activity of chamomile (Matricaria chamomilla L. and feverfew (Tanacetum parthenium L.

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Z Izadi

2013-04-01

Full Text Available Abstract Background & aim: The essential oil of chamomile (Matricaria chamomilla L. and feverfew (Tanacetum parthenium L. are frequently used in pharmaceutical and cosmetic industries. The aim of this study was to investigate the antimicrobial effect of the essential oils of chamomile and chamomile and feverfew. Methods: This experimental study was conducted in 2012 at Hamedan University of Medical Sciences. Essential oils of two medicinal plants species including chamomile and feverfew were obtained by hydrodistillation their constituents were analyzed by GC and GC/MS using retention indices and fragmentation patterns. The antimicrobial effects (MIC and MBC of the essential oils were assessed on a number of microorganisms including gram positive and gram negative bacteria by microdilution technique. The interaction of plant essential oils against microorganisms through differential inhibition index was also evaluated. Data were analyzed by Duncan's multiple range test statistic Results: The minimum inhibitory concentrations of the oils were 0.22-4 and 0.09-1 mg/mlfor chamomile and feverfew respectively. Moreover, the combination of the plants essential oils confirmed synergistic against L. monocytogenes, B. subtilis and B. cereus and additive activities against S. aureus, E. coli and S. typhimorium. Conclusion: The results of this study showed that the application of these essential oils is recommended in combination as an efficients and complementary method for controlling microorganisms. Key words: Chamomile, Feverfew, Antimicrobial Effect

The enzymatic synthesis of rubber polymer in Parthenium argentatum Gray

International Nuclear Information System (INIS)

Benedict, C.R.; Madhavan, S.; Greenblatt, G.A.; Venkatachalam, K.V.; Foster, M.A.

1990-01-01

Washed rubber particles isolated from stem homogenates of Parthenium argentatum Gray by ultracentrifugation and gel filtration on columns of LKB Ultrogel AcA34 contain rubber transferase which catalyzes the polymerization of isopentenyl pyrophosphate into rubber polymer. The polymerization reaction requires Mg 2+ isopentenyl pyrophosphate, and an allylic pyrophosphate. The K m values for Mg 2+ , isopentenyl pyrophosphate, and dimethylallyl pyrophosphate were 5.2 x 10 -4 molar, 8.3 x 10 -5 molar, and 9.6 x 10 -5 molar, respectively. The molecular characteristics of the rubber polymer synthesized from [ 14 C]isopentenyl pyrophosphate were examined by gel permeation chromatography. The peak molecular weight of the radioactive polymer increased from 70,000 in 15 minutes to 750,000 in 3 hours. The weight average molecular weight of the polymer synthesized over a 3 hour period was 1.17 x 10 6 compared to 1.49 x 10 6 for the natural rubber polymer extracted from the rubber particles. Over 90% of the in vitro formation of the rubber polymer was de novo from dimethylallyl pyrophosphate and isopentenyl pyrophosphate. Treatment of the washed rubber particles with 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate solubilized the rubber transferase. The solubilized enzyme(s) catalyzed the polymerization of isopentenyl pyrophosphate into rubber polymer with a peak molecular weight of 1 x 10 5 after 3 hours of incubation with Mg 2+ and dimethylallyl pyrophosphate. The data support the conclusion that the soluble preparation of rubber transferase is capable of catalyzing the formation of a high molecular weight rubber polymer from an allylic pyrophosphate initiator and isopentenyl pyrophosphate monomer

Occurrence of plant sensitivity among patients of photodermatoses: A control-matched study of 156 cases from New Delhi

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Kar Hemanta

2009-01-01

Full Text Available Background: Photodermatitis is an abnormal response to ultraviolet radiation (UVR. The photoallergic contact dermatitis caused by plant allergens is a serious cause of morbidity in India. Airborne contact dermatitis is the classical presentation of plant-induced dermatosis, which may become difficult to differentiate from chronic actinic dermatitis in chronic cases. The rapid growth of parthenium weed in India and its ill effects on the population make it important to detect all cases of parthenium sensitivity, which in some cases might simulate photodermatitis. Aims: This study aims to detect the occurrence of plant sensitivity and photosensitivity in idiopathic-acquired photodermatoses, airborne contact dermatitis and general population taken as controls. Methods: One hundred and fifty six consecutive patients suffering from polymorphic light eruption (PMLE, chronic actinic dermatitis (CAD and airborne contact dermatitis (ABCD were enrolled in the study over a period of three years (June 2004 to May 2007. An equal number of age and sex matched healthy subjects were enrolled in the study as controls. All the patients were subjected to detailed history taking, clinical examination and histopathological examination for diagnosis. Patch and photopatch testing were perfomed in all the patients and healthy controls for detection of allergic and photoallergic reactions to parthenium, xanthium and chrysanthemum plant antigens and control antigens. Results: Out of 156 patients enrolled in the study, 78 (50% had CAD, 67 (42.9% had PMLE and 11 (7.05% had ABCD. The occurrence of parthenium/xanthium allergy and photoallergy, either to parthenium or both was most commonly found in ABCD (72.7%, followed by CAD (32%. In PMLE 4.5% cases showed photoallergy. Only 1.9% in the control group showed sensitivity to parthenium and xanthium. Conclusion: This study indicates that parthenium (and possibly xanthium may act as important environmental factors in the

Physiological, biochemical and defense system responses of parthenium hysterophorus to vehicular exhaust pollution

International Nuclear Information System (INIS)

Khalid, N.; Hussain, M.; Hameed, M.; Ahmad, R.

2017-01-01

Pollution caused by vehicular exhaust emissions detrimentally affect plants and other living beings. This investigation was carried out to evaluate the effects of vehicular exhaust pollutants on Parthenium hysterophorus at various sites along two major roads [Pindi Bhattian to Lillah (M-2) and Faisalabad to Sargodha (FSR)]in the Punjab, Pakistan. Control samples of P. hysterophorus were also collected from 100m away from the roads. Chlorophyll contents, photosynthetic rate, transpiration rate, stomatal conductance, substomatal CO/sub 2/ concentration, water use efficiency, total free amino acids and total antioxidant activity of P. hysterophorus were measured. The results depicted significant reductions in chlorophyll a, chlorophyll b, total chlorophyll and carotenoid contents of P. hysterophorus. Likewise, reduction in stomatal conductance was also recorded which resulted in lowered photosynthetic and transpiration rates. The overall reduction in photosynthetic rate of P. hysterophorus was 30.92% and 35.38% along M-2 and FSR roads, respectively. The limited photosynthesis resulted in increased levels of sub stomatal /sub 2/ concentration and water use efficiency. The elevated levels of free amino acids and total antioxidant activity were noted and could be attributed to activation of plant's defense system to cope with the deleterious effects of vehicular air pollutants. The significant correlations between various attributes of P. hysterophorus with traffic density signifies the stress caused by vehicular emissions. (author)

Glyphosate-Resistant Parthenium hysterophorus in the Caribbean Islands: Non Target Site Resistance and Target Site Resistance in Relation to Resistance Levels.

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Enzo Bracamonte

2016-12-01

Full Text Available Glyphosate has been the most intensely herbicide used worldwide for decades, and continues to be a single tool for controlling weeds in woody crops. However, the adoption of this herbicide in a wide range of culture systems has led to the emergence of resistant weeds. Glyphosate has been widely used primarily on citrus in the Caribbean area, but a study of resistance in the Caribbean islands of Cuba and the Dominican Republic has never been carried out. Unfortunately, Parthenium hysterophorus has developed glyphosate-resistance in both islands, independently. The resistance level and mechanisms of different P. hysterophorus accessions (three collected in Cuba (Cu-R and four collected in the Dominican Republic (Do-R have been studied under greenhouse and laboratory conditions. In in vivo assays (glyphosate dose causing 50% reduction in above-ground vegetative biomass and survival, the resistance factor levels showed susceptible accessions (Cu-S≥Do-S, low-resistance accessions (Cu-R3Do-R2>Cu-R2>Do-R3>Do-R4>Cu-R3>>Cu-S≥Do-S. Glyphosate was degraded to aminomethylphosphonic acid, glyoxylate and sarcosine by >88% in resistant accessions except in Cu-R3 and Do-R4 resistant accessions (51.12 and 44.21, respectively, whereas a little glyphosate (<9.32% was degraded in both susceptible accessions at 96 h after treatment. There were significant differences between P. hysterophorus accessions in the 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS activity enzyme with and without different glyphosate rates. The R accessions showed values of between 0.026 and 0.21 µmol µg-1 TSP protein min-1 basal EPSPS activity values with respect to the S (0.024 and 0.025 accessions. The same trend was found in the EPSPS enzyme activity treated with glyphosate, where a higher enzyme activity inhibition (glyphosate µM corresponded to greater resistance levels in P. hysterophorus accessions. One amino acid substitution was found at position 106 in EPSPS, consisting

Evaluation of Plants and Weeds Extract on the Corrosion Inhibition of Mild Steel in Sulphuric Acid

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Abida Begum

2011-01-01

Full Text Available Experiments were performed in order to determine the inhibitive effects of extracts of plants and weeds namely Parthenium hysterophorus, Dathura stromonium, Azadirachta indica, Helianthus annuus leaves extract for mild steel in sulphuric acid by using weight loss and thermometric technique. Results demonstrated that, all the experimental inhibitors show an adsorption on steel surface according to Langmuir’s isotherm. The inhibition efficiency increased with increase in the concentration of all tested inhibitors to attain a maximum value at 1.0%. Free energy values for adsorption process show that the process is spontaneous. The kinetic treatment of the results shows first order kinetics.

Mechanistic insight into ultrasound induced enhancement of simultaneous saccharification and fermentation of Parthenium hysterophorus for ethanol production.

Science.gov (United States)

Singh, Shuchi; Agarwal, Mayank; Sarma, Shyamali; Goyal, Arun; Moholkar, Vijayanand S

2015-09-01

This paper presents investigations into mechanism of ultrasound assisted bioethanol synthesis using Parthenium hysterophorus biomass through simultaneous saccharification and fermentation (SSF) mode. Approach of coupling experimental results to mathematical model for SSF using Genetic Algorithm based optimization has been adopted. Comparison of model parameters for experiments with mechanical shaking and sonication (10% duty cycle) give an interesting mechanistic account of influence of ultrasound on SSF system. A 4-fold rise in ethanol and cell mass productivity is seen with ultrasound. The analysis reveals following facets of influence of ultrasound on SSF: increase in Monod constant for glucose for cell growth, maximal specific growth rate and inhibition constant of cell growth by glucose and reduction in specific cell death rate. Values of inhibition constant of cell growth by ethanol (K3E), and constants for growth associated (a) and non-growth associated (b) ethanol production remained unaltered with sonication. Beneficial effects of ultrasound are attributed to enhanced cellulose hydrolysis, enhanced trans-membrane transport of substrate and products as well as dilution of the toxic substances due to micro-convection induced by ultrasound. Intrinsic physiological functioning of cells remained unaffected by ultrasound as indicated by unaltered values of K3E, a and b. Copyright © 2015 Elsevier B.V. All rights reserved.

In vitro antibacterial activity of crude methanol extracts of various ...

African Journals Online (AJOL)

Parthenium hysterophorus is an aggressive and exotic weed plant traditionally reported to be used as remedy for various diseases. In the present study in vitro antibacterial activities of P. hysterophorus leaf, flower, bark and root crude methanol extracts were evaluated against five reference strains of pathogenic bacterial ...

Contact dermatitis due to xanthium strumarium

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J S Pasricha

1990-01-01

Full Text Available A 50-year-old mining engineer at Dhanbad was having air bome contact Dermatitis suspected to be caused by Xanthium strumarium. Patch tests with a 15% aqueous extract of air dried leaves showed a severe positive reaction, but the patient also had positive patch tests with Parthenium hysterphorus and a few other weeds and trees known to cause air-borne contact dermatitis. The titre of contact hypersensitivity with the extract of Xanthium struma′rium was more than 1:100,000 and for Parthenium hysterophrous it was 1:10 indicating a high degree of hypersensitivity to Xanthium strumarium. Further tests in 14 other patients revealed a high prevalence of cross sensitivity between these two plants both of which belong to the compositae family.

Photo-patch and patch tests in patients with dermatitis over the photo-exposed areas: A study of 101 cases from a tertiary care centre in India.

Science.gov (United States)

Sharma, Vinod Kumar; Bhari, Neetu; Wadhwani, Ashok Roopchand; Bhatia, Riti

2018-02-01

Many patients with dermatitis over photo-exposed body areas are positive to many contact allergens and have a pre-existing allergic contact dermatitis. This study included patients who presented to a tertiary centre in India with dermatitis on photo-exposed body areas suspected of chronic actinic dermatitis. Their detailed histories were recorded and cutaneous and systemic examinations were performed. Patch testing was done in all the patients and photo-patch testing was carried out in 86 patients. Altogether 101 patients were included (69 males, 32 females). The most common presentation was lichenified hyperpigmented plaques on the photo-exposed sites. Photosensitivity was recorded in 64 (63%) patients and summer exacerbation in 52 (52%). Exposure to the Parthenium hysterophorus weed was recorded in 70 (69%) patients, 27 (26.7%) had a history of hair dye application and 20 (20%) had a history of atopy. Photo-patch test was positive in 11 (12.8%) patients and patch testing was positive in 71 (70%). Parthenium hysterophorus was the most common allergen implicated and was positive in three (4%) photo-patch and 52 (52%) patch tests. Other positive photo-patch test allergens were perfume mix, balsam of Peru, thiuram mix, Compositae mix and promethazine hydrochloride. Other common patch test allergens were parthenolide, colophony, fragrance mix and p-phenylenediamine (PPD) base. In the Indian population parthenium and perfume mix are the most common photoallergens in patients with dermatitis over photo-exposed areas, while parthenium, colophony, fragrance mix and PPD are the common positive allergens. © 2016 The Australasian College of Dermatologists.

Air-borne contact dermatitis caused exclusively by xanthium strumarium.

Science.gov (United States)

Pasricha, J S; Verma, K K; D'Souza, P

1995-01-01

Most cases having air-borne contact dermatitis (ABCD) in India are considered to be caused by Parthenium hysterophorus. In some cases however, other plants have also been noticed to give positive patch test reactions. We are reporting two cases presenting as ABCD who showed positive patch tests with Xanthium strumarium while the patch tests with Parthenium hysterophorus were negative. It is therefore necessary to realise that every case of ABCD is not caused by Parthenium, and patch testing with Parthenium alone can lead to serious mistakes.

Varietal Response of Chickpea (Cicer arietinum L.) Towards the Allelopathy of Different Weeds

International Nuclear Information System (INIS)

Rahamdad, K.; Ijaz, A.K.

2015-01-01

In a laboratory trial three chickpea varieties viz, Karak-I, Karak-III and Shenghar were tested against the phytotoxicity of five weed species: Parthenium hysterophorus L., Phragmites australis (Cav.) Trin., Datura alba L., Cyperus rotundus L. and Convolvulus arvensis L.in January 2013. The weed extracts were prepared at the rate of 120 g/L (w/v) after shade dry. The results indicated highly significant inhibitory effect of all the tested weed species on the chickpea varieties. The results also showed that the chickpea variety Karak-III was more susceptible to the phototoxicity of the tested weed extracts. Among the extract, C. arvensis proved much toxic in term of inhibition of germination by giving only 43.33% germination in comparison with control where 97.50% germination was recorded. On the other hand, the effect of P. australis extract was found a little stimulator by speeding the seed germination in all varieties and giving a low (2.21) mean germination time (MGT) value. From the current results it can be concluded that the infestation of C. arvensis can pollute the soil by accumulating toxic chemicals that leads to the germination failure and growth suppression in chickpea. Therefore, the prevention and removal of C. arvensis in the chickpea growing areas could be recommended. In addition, P. australis must be tested against chickpea weeds (chickpea varieties withstand against its phototoxicity), so that it can be popularized as bio herbicide in chickpea if it gave promising results in controlling chickpea weeds. (author)

Air-borne contact dermatitis caused exclusively by xanthium strumarium

Directory of Open Access Journals (Sweden)

Pasricha J

1995-01-01

Full Text Available Most cases having air-borne contact dermatitis (ABCD in India are considered to be caused by Parthenium hysterophorus. In some cases however, other plants have also been noticed to give positive patch test reactions. We are reporting two cases presenting as ABCD who showed positive patch tests with Xanthium strumarium while the patch tests with Parthenium hysterophorus were negative. It is therefore necessary to realise that every case of ABCD is not caused by Parthenium, and patch testing with Parthenium alone can lead to serious mistakes.

Parthenium sp. as a plant biomass for the production of alkalitolerant xylanase from mutant Penicillium oxalicum SAUE-3.510 in submerged fermentation

International Nuclear Information System (INIS)

Dwivedi, Pallavi; Vivekanand, V.; Ganguly, Ruma; Singh, Rajesh P.

2009-01-01

The use of congress grass (Parthenium sp.) and water hyacinth (Eichhornia crassipes) as low cost raw materials for xylanase production from mutant Penicillium oxalicum SAU E -3.510 in submerged fermentation was investigated. For development of mutant from wild type P. oxalicum SA-8 ITCC 6024, a strategy of mixed mutagenesis was followed using UV-irradiation and ethidium bromide, which had resulted into 1.87 fold increases in the activity of the enzyme. For enzyme production, the fungus was cultivated in mineral medium containing congress grass as carbon source. Considerably higher levels of production (475.2 ± 6.0 IU ml -1 ) were achieved in media containing congress grass, although it was slightly less than that was obtained (488.5 ± 6.5 IU ml -1 ) in presence of commercial oat spelt xylan. This fact confirms the feasibility of using this low cost non-food resource as an alternative carbon source to save costs of the enzyme production process. Maximum xylanase activity was reported at 55 deg. C with its stability at 80 deg. C for 2 h. The highest activity of xylanase at pH 9.0 and its stability at similar pH for 24 h denote the alkalitolerant nature of enzyme

Projecting future expansion of invasive species: comparing and improving methodologies for species distribution modeling.

Science.gov (United States)

Mainali, Kumar P; Warren, Dan L; Dhileepan, Kunjithapatham; McConnachie, Andrew; Strathie, Lorraine; Hassan, Gul; Karki, Debendra; Shrestha, Bharat B; Parmesan, Camille

2015-12-01

. However, discrepancies between model predictions and parthenium invasion in Australia indicate successful management for this globally significant weed. © 2015 John Wiley & Sons Ltd.

Parthenium sp. as a plant biomass for the production of alkalitolerant xylanase from mutant Penicillium oxalicum SAU{sub E}-3.510 in submerged fermentation

Energy Technology Data Exchange (ETDEWEB)

Dwivedi, Pallavi; Vivekanand, V.; Ganguly, Ruma; Singh, Rajesh P. [Department of Biotechnology, Indian Institute of Technology Roorkee, Roorkee 247667 (India)

2009-04-15

The use of congress grass (Parthenium sp.) and water hyacinth (Eichhornia crassipes) as low cost raw materials for xylanase production from mutant Penicillium oxalicum SAU{sub E}-3.510 in submerged fermentation was investigated. For development of mutant from wild type P. oxalicum SA-8 ITCC 6024, a strategy of mixed mutagenesis was followed using UV-irradiation and ethidium bromide, which had resulted into 1.87 fold increases in the activity of the enzyme. For enzyme production, the fungus was cultivated in mineral medium containing congress grass as carbon source. Considerably higher levels of production (475.2 {+-} 6.0 IU ml{sup -1}) were achieved in media containing congress grass, although it was slightly less than that was obtained (488.5 {+-} 6.5 IU ml{sup -1}) in presence of commercial oat spelt xylan. This fact confirms the feasibility of using this low cost non-food resource as an alternative carbon source to save costs of the enzyme production process. Maximum xylanase activity was reported at 55 C with its stability at 80 C for 2 h. The highest activity of xylanase at pH 9.0 and its stability at similar pH for 24 h denote the alkalitolerant nature of enzyme. (author)

An approach to the development of a national strategy for controlling invasive alien plant species: The case of Parthenium hysterophorus in South Africa

Directory of Open Access Journals (Sweden)

Colette Terblanche

2016-06-01

Full Text Available Invasive alien species require co-ordinated strategic management if negative impacts are to be effectively avoided. Here we describe a strategy for the management of Parthenium hysterophorus L. (Asteraceae in South Africa. P. hysterophorus is an annual herb native to tropical America, which has become invasive in over 30 countries. The strategy sets goals for (1 the prevention of spread to new areas; (2 local eradication of isolated populations; (3 containment in areas where eradication is not possible; and (4 actions to protect assets where containment is no longer an option. We developed both a national strategy to set policy and to monitor progress towards goals at a national level and an implementation plan to set goals and timeframes for their achievement at local levels. It is not clear, at this stage, whether or not the goals of the strategy are achievable because implementation will face many challenges arising from ecological features of the target plant, social and cultural practices that will influence management, inadequate levels of funding and multiple political considerations. Our strategy proposes regular assessment using high-level indicators, a practice that is widely recognised as essential but seldom implemented at a national scale. Because the outcomes are uncertain, it is vital that regular monitoring of outcomes should be instituted from the start, so that both appropriate adjustments can be made to the strategy and lessons for the implementation of similar strategies elsewhere can be derived.

Management of parthenium weed by extracts and residue of wheat

African Journals Online (AJOL)

Ehsan Zaidi

2011-10-24

Oct 24, 2011 ... bioassay, dried and chopped wheat straw of the four test wheat varieties was thoroughly mixed in pot ... environment from living plants and the subsequent ... Copped materials were mixed in sandy loam soil in plastic pots of 8.

Chromium toxicity tolerance of Solanum nigrum L. and Parthenium hysterophorus L. plants with reference to ion pattern, antioxidation activity and root exudation.

Science.gov (United States)

UdDin, Islam; Bano, Asghari; Masood, Sajid

2015-03-01

Chromium (Cr), being a highly toxic metal, adversely affects the mineral uptake and metabolic processes in plants when present in excess. The current study was aimed at investigating the Cr accumulation in various plant tissues and its relation to the antioxidation activity and root exudation. Plants were grown in soil spiked with different concentrations of Cr for three weeks in pots and analysed for different growth, antioxidants and ion attributes. Furthermore, plants treated with different concentrations of Cr in pots were shifted to rhizobox-like system for 48h and organic acids were monitored in the mucilage dissolved from the plant root surface, mirroring rhizospheric solution. The results revealed that the Cr application at 1mM increased the shoot fresh and dry weight and root dry weight of Solanum nigrum, whereas the opposite was observed for Parthenium hysterophorus when compared with lower levels of Cr (0.5mM) or control treatment. In both plant species, Cr and Cl concentrations were increased while Ca, Mg and K concentrations in root, shoot and root exudates were decreased with increasing levels of Cr. Higher levels of Cr treatments enhanced the activities of SOD, POD and proline content in leaves of S. nigrum, whereas lower levels of Cr treatment were found to have stimulatory effects in P. hysterophorus. P. hysterophorus exhibited highest exudation of organic acid contents. With increasing levels of Cr treatments, citric acid concentration in root exudates increased by 35% and 44% in S. nigrum, whereas 20% and 76% in P. hysterophorus. Cr toxicity was responsible for the shoot growth reduction of S. nigrum and P. hysterophorus, however, shoot growth response was different at different levels of applied Cr. Consequently, Cr stress negatively altered the plant physiology and biochemistry. However, the enhanced antioxidant production, Cl uptake and root exudation are the physiological and biochemical indicators for the plant adaptations in biotic systems

Contact Dermatitis Due to Plants in Chandigarh

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K Vinod Sharma

1987-01-01

Full Text Available Two hundred and seven patients (151 males and 56 females were patch tested with a battery of plants, potassium dichromate and formaldehyde. Sensitivity to Parthenium hysterophorus. Nerium indicum, Calotropis procera, Eucalyptus sp and Mangifera indica was found in 60.87, 23.64, 15.46 andl2.08% patients respectively. One hundred and twenty six patients (92 males and 34 females including five teenage girls and one 13 years old child had parthenium dermatitis. Majority (74.60% were between 30 to 59 years of age. Dermatitis involving face especially eyelids, neck, cubital and popliteal fossae was the common (82.54% mode of presentation. Photosensitive pattern was seen in 9.51% and chronic lichenification of extremities in the remaining 7.97% patients Parthenium dermatitis was seen more frequently in city dwellers, while farmers constituted only 20.7% of all cases. There was frequent patch test positivity to potassium dichromate (24.i5% and formaline (28.02% in the present patients.

Studies using nuclear and complementary non-nuclear analytical techniques for bio-monitoring of air pollution

International Nuclear Information System (INIS)

Arunachalam, J.; Karunasagar, D.; Kumar, S.; Sahayam, A.C.

1999-01-01

A set of lower and higher plants have been analysed for their trace element contents. The plants are, a moss (Funaria sp.), a bryophyte (Cyathodium sp.), a weed (Parthenium hysterophorus L.) and a common bushy shrub (Lantana Camera L.). The trace element concentrations have been determined using INAA, PIGE and ICP-OES. The data are examined with a view to assess the use of these plants as bio-indicators of toxic trace metal pollutants in ambient air. The moss and the bryophyte samples show much higher accumulation levels for many elements, but are seasonal. The other two plants, due to their perennial nature, can be used for bio-monitoring purposes, almost throughout the year. (author)

Study Of Clinical Profile of Allergic Contact Dermatitis In Pune

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Sayal S K

1999-01-01

Full Text Available One hundred and twenty five cases of clinically diagnosed allergic contact dermatitis were studied. All patients were subjected to patch test with standard test allergens and also with suspected test allergens based on history and clinical profile. Allergic contact dermatitis due to Parthenium hysterophorus was commonest and found in 64% cases, followed by wearing apparel and jewellery in 16.8%, topical medicaments in 8% and cosmetics and occupational contactants in 5.6% cases each. The common individual allergens other than parthenium, were nickel in 8.8%, leather, hair dye and cement in 3.2% each, nitrofurazone and petrol, oil, lubricant (POL in 2.4% each. Patch test with suspected allergens was positive in 72% of cases.

Identification of common allergens for united airway disease by skin prick test

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Vikas Deep Mishra

2016-01-01

Full Text Available Objective: Identification of common allergens by skin prick test in patients of united airway disease. Materials and Methods: Skin prick test was performed in 60 patients of United Airway Disease to identify the common allergens. A total of 62 allergens consisting of 36 types of pollen, 5 fungi, 4 insects, 8 type of dusts, 4 dander, 3 fabrics, Dust mite and Parthenium leaves were tested. Result: Most common allergens were Dust mite (60% followed by Parthenium leaves (45%, insects (18.75%, pollen (14.81%, dust allergens (8.51%, fabrics (8.33%, fungi (5.66%, dander (5%. Most common insect allergens were cockroach (female (30%, cockroach (male (23.33%. Common pollens were Ricinus communis (28.33%, Amaranthus spinosus (28.33%, Parthenium hysterophorus (26.66%, Eucalyptus tereticornis (26.66% and Cynodon dactylon (25%. Common dust allergens were house dust (21.66%, paper dust (11.66% and cotton mill dust (10%. Among fabrics kapok cotton (13.33% showed maximum positivity. Among fungi Aspergillus fumigatus (10% followed by A. niger (6.66% were most common. In animal dander group common ones were cat dander followed by dog dander. Conclusion: In conclusion it can be said that the knowledge drawn by above study will help to treat patients by immunotherapy or avoidance strategy.

Terpenoids for medicine

NARCIS (Netherlands)

Fischedick, Justin

2013-01-01

This thesis is concerns research on monoterpenoids, sesquiterpenoids, and diterpenoids with medicinal properties. Terpenoids from commond herbs as well as Cannabis sativa, Inula britannica, Tanacetum parthenium, and Salvia officinalis were investigated

African Journal of Environmental Science and Technology - Vol 2 ...

African Journals Online (AJOL)

Pathogenic diversity of Sclerotium rolfsii isolates, a potential biocontrol agent against Parthenium hysterophorus L. EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT. R Shukla, A.K. Pandey, 124-126 ...

Natural rubber producing plants: An overview | Venkatachalam ...

African Journals Online (AJOL)

... Hevea and also other natural rubber producing species for alternative source of latex production in the near future. Keywords: Alternative rubber sources, biotechnology, breeding, Hevea brasiliensis, Parthenium argentatum, Taraxacum koksaghyz, Ficus bengalensis, Lactuca serriola. African Journal of Biotechnology Vol.

Oils and rubber from arid land plants

Science.gov (United States)

Johnson, J. D.; Hinman, C. W.

1980-05-01

In this article the economic development potentials of Cucurbita species (buffalo gourd and others), Simmondsia chinensis (jojoba), Euphorbia lathyris (gopher plant), and Parthenium argentatum (guayule) are discussed. All of these plants may become important sources of oils or rubber.

Vegetation Composition, Biomass Production, Carrying Capacity ...

African Journals Online (AJOL)

Acacia tortilis, Acacia nilotica, Acacia mellifera and Acacia seyal were the most dominant shrubs with scattered Caddaba rotundifolia, Caddaba furmisa, Seddera bagshawei, Tamarix nilotica, Dobera glabra and abundant Parthenium hysterophorus, Cissus rotundifolia and C. quadrangularis. The grass biomass estimated in ...

Observations on antifertility and abortifacient herbal drugs | Shah ...

African Journals Online (AJOL)

Plur., Buddleja asiatica Lour, Chrysanthemum parthenium (L.) Bernh, Justacia adhatod L., Ricinus communis L., Zingiber officinale Roscol., Daucus crota L., Momordica charantia L., Plumbago zeylanica L., Sapindus mukorossi Gaertn., Plantago ovata Forssk, Tanacetum vulgare and Arctium lappa L. The most widely used ...

Photopatch and UV-irradiated patch testing in photosensitive dermatitis

Directory of Open Access Journals (Sweden)

Reena Rai

2016-01-01

Full Text Available Background: The photopatch test is used to detect photoallergic reactions to various antigens such as sunscreens and drugs. Photosensitive dermatitis can be caused due to antigens like parthenium, fragrances, rubbers and metals. The photopatch test does not contain these antigens. Therefore, the Indian Standard Series (ISS along with the Standard photopatch series from Chemotechnique Diagnostics, Sweden was used to detect light induced antigens. Aim: To detect light induced antigens in patients with photosensitive dermatitis. Methods: This study was done in a descriptive, observer blinded manner. Photopatch test and ISS were applied in duplicate on the patient's back by the standard method. After 24 hours, readings were recorded according to ICDRG criteria. One side was closed and other side irradiated with 14 J/cm2 of UVA and a second set of readings were recorded after 48 hrs. Result: The highest positivity was obtained with parthenium, with 18 out of 35 (51% patients showing a positive patch test reaction with both photoallergic contact dermatitis and photoaggravation. Four patients (11% showed positive patch test reaction suggestive of contact dermatitis to potassium dichromate and fragrance mix. Six patients had contact dermatitis to numerous antigens such as nickel, cobalt, chinoform and para-phenylenediamine. None of these patients showed photoaggravation on patch testing. Conclusion: Parthenium was found to cause photoallergy, contact dermatitis with photoaggravation and contact allergy. Hence, photopatch test and UV irradiated patch test can be an important tool to detect light induced antigens in patients with photosensitive dermatitis.

Vesicular-arbuscular mycorrhizae in jojoba and mariola

Energy Technology Data Exchange (ETDEWEB)

Bloss, H E

1975-01-01

Glomus fasculatus was isolated from soil and roots of the indigenous desert plants Parthenium incanum and Simmondsia chinensis, possible sources of rubber and a waxy oil, respectively. It is suggested that inoculation of these plants with mycorrhizal G. spp. could enhance their productivity under cultivation.

Down-Regulation of Small Rubber Particle Protein Expression Affects Integrity of Rubber Particles and Rubber Content in Taraxacum brevicorniculatum

Czech Academy of Sciences Publication Activity Database

Hillebrand, A.; Post, J. J.; Wurbs, D.; Wahler, D.; Lenders, D.; Krzyžánek, Vladislav; Pruefer, D.; Gronover, CH. S.

2012-01-01

Roč. 7, č. 7 (2012), e41874:1-9 E-ISSN 1932-6203 Institutional support: RVO:68081731 Keywords : Hevea - Brasiliensis * Parthenium-Argentatum * Elongation-Factor * Silencing Affects * Surface-Structure * Oil Bodies * Latex * Prenyltransferase * Biosynthesis * Stability Subject RIV: CE - Biochemistry Impact factor: 3.730, year: 2012

Evaluation of anticancer properties of a new α-methylene-δ-lactone DL-249 on two cancer cell lines

Directory of Open Access Journals (Sweden)

Pomorska Dorota K.

2017-06-01

Full Text Available The anticancer activity of a new synthetic α-methylene-δ-lactone DL-249 was reported in leukemia HL-60 and breast cancer MCF-7 cells and compared with the activity of a natural α-methylene-γ-lactone from Tanacetum parthenium, parthenolide.

Elucidation and in planta reconstitution of the parthenolide biosynthetic pathway

DEFF Research Database (Denmark)

Liu, Qing; Manzano, David; Tanić, Nikola

2014-01-01

Parthenolide, the main bioactive compound of the medicinal plant feverfew (Tanacetum parthenium), is a promising anti-cancer drug. However, the biosynthetic pathway of parthenolide has not been elucidated yet. Here we report on the isolation and characterization of all the genes from feverfew tha...

Proteins and amino acids as biobased polymer modifiers

Science.gov (United States)

Natural rubber (NR) is a critical agricultural material vital to industry, medicine, and defense, yet global supply is largely limited to latex from Hevea brasiliensis cultivated in tropical regions. Guayule (Parthenium argentatum), a woody desert shrub indigenous to the U.S. and Mexico, is under de...

Herbicidal effects of aqueous extracts of three Chenopodium ...

African Journals Online (AJOL)

Jane

2011-04-07

Apr 7, 2011 ... root extract of Sorghum halepense stimulated seedling shoot length of Parthenium hysterophorus. Similar effects of the aqueous extracts of Inula grantioides Boiss. and. Capsicum annuum L. on seedling growth of test species have also been demonstrated against various test species by Shaukat et al.

Pathogenic diversity of Sclerotium rolfsii isolates, a potential ...

African Journals Online (AJOL)

Administrator

et al., 2002; Shukla and Pandey, 2007). Therefore, present investigation was carried out to study the pathogenic varia- bility and justify the separate identity of the S. rolfsii isolates associated with Parthenium. MATERIALS AND METHODS. Test isolates and their maintenance. Ten isolates of S. rolfsii incites collar rot disease ...

Biological and technological effects of some mulberry varieties and ...

African Journals Online (AJOL)

egyptian hak

Rapid industrialization, increases in greenhouse gases in the atmosphere, ... entire agricultural production system through direct or indirect effects on crops, ... to India along with wheat grains under the PL 480 scheme from USA; it has .... water just before use; 1 N NaOH.0.5 grams fresh leaf material of Parthenium were.

[Compositae dermatitis].

Science.gov (United States)

Jovanović, Marina; Poljacki, Mirjana

2003-01-01

Compositae dermatitis is an allergic contact dermatitis caused by plant species of the Compositae family. The first report of a cutaneous reaction to the Chrysanthemum genus was made by Howe JS in 1887. In 1895 Maiden JH reported about skin lesions among men working with Tagetes minuta. Case reports of contact allergic-ragweed dermatitis appeared in the American literature as early as 1919. The North American feverfew--Parthenium Hysterophorus was brought to India from America in 1956 and it caused thousands of cases of so-called parthenium dermatitis. Ragweed and parthenium dermatitis became prototypes for the classic, so-called "airborne" Compositae dermatitis, that affects primarily exposed skin surfaces, and produces a universal erythroderma. The frequency of contact allergy to Compositae in Europe is higher than previously believed. It occurs most frequently in middle-aged and elderly persons, but also in all age groups. During the two past decades a more equal sex ratio has been established. The prevalence varies from 0.7-1.4% in the general population, up to 4.5% among occupationally exposed persons. Compositae allergy is among the top ten contact sensitivities in Europe. In North Europe plants were the cause of 4.4% cases of occupational allergic contact dermatitis. ETIOLOGY AND PATHOGENESIS: Among cultivated Compositae plants, Chrysanthemum is considered to be a major sensitizer in Europe (60%). Among the edible types, it is lettuce--Lactuca sativa and endive Cichorium endivia (20-30%), and wild-growing feverfew--Tanace--tum parthenium (70-90%), tansy--Tanacetum vulgare (54%), and dandelion--Taraxacum officinale (65%). Sesquiterpene lactones are the main sensitizers of the Compositae family. Other components, thiophenes and acetylenes are said to elicit only phytophotodermatitis, but recent studies have demonstrated that some thiophenes and benzofuran derivates possess not only phototoxic activity, but also sensitizing properties. Photosensitivity is

Protective effect of Parthenium hysterophorus against carbon ...

African Journals Online (AJOL)

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Results: Pre-treatment of rabbits with Ph.Cr reduced ALT, ALP and TB levels (p ... treatment of liver disorders. Because of more effectiveness, less consequences of side effects and low cost, natural remedies are now .... showed hepatocyte necrosis, vacuolization of ..... myocardium, cardiac pacemakers and vascular smooth.

Airborne Compositae dermatitis

DEFF Research Database (Denmark)

Christensen, Lars Porskjær; Jakobsen, Henrik Byrial; Paulsen, E.

1999-01-01

The air around intact feverfew (Tanacetum parthenium) plants was examined for the presence of airborne parthenolide and other potential allergens using a high-volume air sampler and a dynamic headspace technique. No particle-bound parthenolide was detected in the former. Among volatiles emitted f...... for airborne Compositae dermatitis. Potential allergens were found among the emitted monoterpenes and their importance in airborne Compositae dermatitis is discussed....

Efficacy of Jatropha, Annona and Parthenium biowash on ...

African Journals Online (AJOL)

... rot in chickpea) and Macrophomina phaseolina (causes charcoal rot in sorghum). ... crude biowash was also passed through C18 solid phase extraction cartridges and ... When the organic fraction of Jatropha biowash was further fractionated by ... Hence, it was concluded that one of these three bands could be the active

Compositae dermatitis

OpenAIRE

Jovanović Mirjana; Poljački Mirjana N.

2003-01-01

Introduction Compositae dermatitis is an allergic contact dermatitis caused by plant species of the Compositae family. The first report of a cutaneous reaction to the Chrysanthemum genus was made by Howe JS in 1887. In 1895 Maiden JH reported about skin lesions among men working with Tagetes minute Case reports of contact allergic-ragweed dermatitis appeared in the American literature as early as 1919. The North American feverfew - Parthenium Hysterophorus was brought to India from America in...

Robotic weeding and automated weed measurements

DEFF Research Database (Denmark)

Christensen, S.; Søgaard, H.T.; Jørgensen, R.N.

2003-01-01

The goal of decreasing herbicide usage has so far focused on reducing the herbicide dosage or replacing chemical weed control by hoeing and harrowing. The conventional weed control strategy is to apply the same dose of herbicide or the same intensity of hoeing and harrowing in the whole field. Th...... the state-of-the-art of automated weed measurement methods and the research projects concerning autonomous platform and information system for crop and weed monitoring and robotic weeding....

Citotoxicidad de extractos de plantas medicinales sobre la línea celular de carcinoma de pulmón humano A549

Directory of Open Access Journals (Sweden)

Alexis Díaz García

2011-03-01

Full Text Available OBJETIVO: evaluar el efecto de 10 extractos de plantas medicinales sobre el crecimiento de la línea celular humana de carcinoma de pulmón A549. METODOS: el efecto de los extractos sobre la células tumorales se midió a través de un ensayo colorimétrico mediante el empleo del bromuro de 3-(4,5-dimetil-tiazol-2-yl-2,5-difenil tetrazolio a concentraciones entre 3,9-250 µg/mL durante 72 h y se calculó la concentración citotóxica media para cada uno. RESULTADOS: del total de los extractos evaluados solo cuatro (Parthenium hysterophorus, Bixa orellana, Momordica charantia y Cucurbita maxima evidenciaron concentraciones citotóxicas medias inferiores a 100 µg/mL. Excepto Parthenium hysterophorus, las restantes se emplean en la medicina tradicional para el tratamiento del cáncer. Los extractos de Cecropia peltata, Melia azedarach, Annona glabra, Artemisia absintium, Lepidium virginicum y Bidens pilosa no mostraron efectos citotóxicos significativos. CONCLUSIONES: Los extractos de plantas que se emplean en la medicina tradicional para el tratamiento del cáncer, mostraron citotoxicidad sobre las células tumorales. El conocimiento etnobotánico representa una herramienta importante en la selección de plantas medicinales, en la búsqueda de nuevos compuestos para el tratamiento del cáncer.

Clinical profile and quality of life of patients with occupational contact dermatitis from New Delhi, India.

Science.gov (United States)

Bhatia, Riti; Sharma, Vinod K; Ramam, M; Sethuraman, Gomathy; Yadav, Chander P

2015-09-01

Data regarding occupational contact dermatitis (OCD) and its effect on quality of life (QOL) in India are limited. To evaluate patients with OCD and record the outcome of treatment. All patients with OCD were evaluated for severity of disease (by the use of physician global assessment) and its effect on QOL (by use of the Dermatology Life Quality Index) questionnaire) at the first visit and after 3 months of treatment. Among 117 patients with OCD, hand eczema was present in 81.2%. Positive patch test reactions were found in 76%. The most common allergens were Parthenium hysterophorus and potassium dichromate. The most frequent diagnosis was occupational allergic contact dermatitis (OACD) (57%), caused by farming and construction work, followed by occupational irritant contact dermatitis (OICD) (24%), caused by wet work. Severe psychosocial distress was recorded in 62.5% of patients. After 3 months of treatment, 83% improved significantly, and 54% had improvement in QOL. Farmers were most frequently affected, followed by construction workers and housewives. OACD was found at a higher frequency than OICD. The most frequent allergens were Parthenium hysterophorus in farmers, potassium dichromate in construction workers, and vegetables in housewives. OCD has a significant impact on QOL. Patch testing, in addition to standard treatment, improves the outcome considerably. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Presence of radioactive minerals in the blast furnace slag of Tata steel and their bioaccumulation by some naturally growing plants

Energy Technology Data Exchange (ETDEWEB)

Singh, V K; Tej, P P [Dept. of Botany, Post Graduate Centre, Jamshedpur Co-Operative College, Jamshedpur (India)

2005-07-01

Twelve species of plants were sampled from the slag dumping area of Jamshedpur. Chemical analysis of soil as well as vegetation sample was carried out to detect the presence of {sup 238}U and {sup 226}Ra. The concentration of these two radionuclides was found to be elevated over the background sample. Commelina benghalensis, Parthenium hysterophorus, Andrographis paniculata, registered higher values of these radionuclides in their different organs. Such plants can be gainfully exploited for eco-restoration programme through phyto-remediation of the contaminated substratum. (author)

Presence of radioactive minerals in the blast furnace slag of Tata steel and their bioaccumulation by some naturally growing plants

International Nuclear Information System (INIS)

Singh, V.K.; Tej, P.P.

2005-01-01

Twelve species of plants were sampled from the slag dumping area of Jamshedpur. Chemical analysis of soil as well as vegetation sample was carried out to detect the presence of 238 U and 226 Ra. The concentration of these two radionuclides was found to be elevated over the background sample. Commelina benghalensis, Parthenium hysterophorus, Andrographis paniculata, registered higher values of these radionuclides in their different organs. Such plants can be gainfully exploited for eco-restoration programme through phyto-remediation of the contaminated substratum. (author)

Toward a global information system for invasive species

Science.gov (United States)

Ricciardi, Anthony; Steiner, William W.M.; Mack, Richard N.; Simberloff, Daniel

2000-01-01

The growing frequency and impact of biological invasions worldwide threaten biodiversity, ecosystem functioning, resource availability, national economies, and human health (Ruesink et al. 1995, Simberloff 1996, Vitousek et al. 1997). Organisms are spreading into new regions at unprecedented rates. As a result, hundreds to thousands of nonindigenous species of invertebrates, vertebrates, plants, bacteria, and fungi have become established in all but the most remote areas of the planet (Vitousek et al. 1997). Recent examples are abundant and, in some cases, alarming. Cholera bacteria and toxic dinoflagellates have been discovered in the ballast waters of cargo ships (McCarthy and Khambaty 1994, Hallegraeff 1998). Asian tiger mosquitos—vectors of yellow fever and encephalitis—have spread to new continents in imported truck tires (Moore et al. 1988). Pasture and crop lands in Australia are being invaded by Parthenium, an aggressive Caribbean weed that causes severe allergic reactions in livestock and humans (Evans 1997). Rapid and widespread dieoffs of native freshwater mussels are occurring in the wake of the zebra mussel invasion in North America (Ricciardi et al. 1998). [[AQ4]Hardwood trees in American cities are being killed by Asian long-horned beetles introduced with wooden packing crates (Haack et al. 1997).

Weeds and Wildlife: Perceptions and Practices of Weed Managers

Directory of Open Access Journals (Sweden)

Emma H Carlos

2014-01-01

Full Text Available Negative impacts of invasive plants or weeds on biodiversity have been well established yet their role in providing key habitats and resources for wildlife has been little understood. Weed removal thus has the potential to adversely affect wildlife but whether this is considered during weed management is poorly known. To determine the extent of this knowledge, we examined the perceptions of weed managers regarding wildlife and weed management in Victoria, Australia. We surveyed 81 weed managers of varying levels of experience from different types of organisations, including state and local government, community groups and private companies. We found 90% of managers had observed wildlife-weed interactions and that most (70% adjusted management programmes to accommodate wildlife. Despite this, few (19% had adopted the recommended practice of combining gradual weed removal with re-vegetation. While management programmes included monitoring of native vegetation, consideration of wildlife monitoring in weed management was rare. This highlights the need for management to better understand and respond to wildlife-weed relationships. If the improvement of wildlife habitat is included in the objectives of weed programmes, as it should be, then wildlife should also be incorporated in project monitoring. This would lead to a greater understanding of the role weeds and their management have in each situation and, ultimately, more informed decision making.

Citotoxicidad de extractos de plantas medicinales sobre la línea celular de carcinoma de pulmón humano A549 Cytotoxicity of medicinal plant extracts on the human lung carcinoma cell line A549

Directory of Open Access Journals (Sweden)

Alexis Díaz García

2011-03-01

Full Text Available OBJETIVO: evaluar el efecto de 10 extractos de plantas medicinales sobre el crecimiento de la línea celular humana de carcinoma de pulmón A549. METODOS: el efecto de los extractos sobre la células tumorales se midió a través de un ensayo colorimétrico mediante el empleo del bromuro de 3-(4,5-dimetil-tiazol-2-yl-2,5-difenil tetrazolio a concentraciones entre 3,9-250 µg/mL durante 72 h y se calculó la concentración citotóxica media para cada uno. RESULTADOS: del total de los extractos evaluados solo cuatro (Parthenium hysterophorus, Bixa orellana, Momordica charantia y Cucurbita maxima evidenciaron concentraciones citotóxicas medias inferiores a 100 µg/mL. Excepto Parthenium hysterophorus, las restantes se emplean en la medicina tradicional para el tratamiento del cáncer. Los extractos de Cecropia peltata, Melia azedarach, Annona glabra, Artemisia absintium, Lepidium virginicum y Bidens pilosa no mostraron efectos citotóxicos significativos. CONCLUSIONES: Los extractos de plantas que se emplean en la medicina tradicional para el tratamiento del cáncer, mostraron citotoxicidad sobre las células tumorales. El conocimiento etnobotánico representa una herramienta importante en la selección de plantas medicinales, en la búsqueda de nuevos compuestos para el tratamiento del cáncer.OBJECTIVES: to evaluate the effect of 10 Cuban medicinal plant extracts on the human lung tumor cell line A549. METHODS: the effect of the plant extracts on tumor cells was determined by a colorimetric assay using the 3-(4,5-Dimethylthiazol-2-yl-2,5-diphenyltetrazolium bromide (MTT at concentrations ranging from 3,9-250 µg/mL for 72 hours and the mean cytotoxic concentration was calculated for each of them. RESULTS: the ethanolic extracts of Parthenium hysterophorus, Bixa orellana, Momordica charantia and Cucurbita maxima showed mean cytotoxic concentrations under 100 µg/mL. Except for P. hysterophorus, the others are used in traditional medicine to fight

Guayule and jojoba: agriculture in semi-arid regions

Energy Technology Data Exchange (ETDEWEB)

Maugh, II, T H

1977-01-01

A discussion on the possible culture on Indian lands of jojoba (Simmondsia chinensis), whose seeds contain up to 60% liquid wax. It tolerates saline alkaline soil and saline irrigation water. One hectare of 5-year-old jojoba should yield 200 kg of oil without genetic improvement. Guayule (Parthenium argentatum) may become important once again as an American source of rubber. Other species requiring further research include Euphorbia lathyrus and E. tirucalli, as sources of hydrocarbons, and Cucurbita foetidessima, which produces an edible oil with up to 35% protein.

Weed flora, yield losses and weed control in cotton crop

OpenAIRE

Jabran, Khawar

2016-01-01

Cotton (Gossypium spp.) is the most important fiber crop of world and provides fiber, oil, and animals meals. Weeds interfere with the growth activities of cotton plants and compete with it for resources. All kinds of weeds (grasses, sedges, and broadleaves) have been noted to infest cotton crop. Weeds can cause more than 30% decrease in cotton productivity. Several methods are available for weed control in cotton. Cultural control carries significance for weed control up to a certain extent....

Crop–weed competition

DEFF Research Database (Denmark)

Gallandt, Eric R.; Weiner, Jacob

2015-01-01

importantly, weed density and time of emergence relative to the crop. Practices that (1) reduce the density of weeds, (2) maximise occupation of space or uptake of resources by the crop or (3) establish an early-season size advantage of the crop over the weeds will minimise the competitive effects of weeds...... on crops. Longer term management of crop–weed competition can be achieved through crop rotations, specifically crop sequences that reduce the weed seed bank, and therefore seedling density, and prevent proliferation of perennial weeds. Key ConceptsKey Concepts * Plant growth requires sunlight, water...... an early-season competitive advantage to the crop and (3) maximising resource capture by the crop using competitive species, competitive cultivars, high sowing densities, optimal spatial arrangement, intercropping complimentary species or transplanting....

About the value of species diversity in arable weeds for weed management

Directory of Open Access Journals (Sweden)

Gerowitt, Bärbel

2016-02-01

Full Text Available Arable weeds accompany arable land use – we define them based on their affiliation to ar able systems. They are adapted to such a degree that most of them cannot exist without arable land use. Weeds are part of the total biodiversity on arable fields, as primary producers they are basic for important functions within the ecosystem. This paper elaborates the relevance of species diversity in arable weeds for their management. Arable systems can be regarded for the number of different methods for preventive and direct weed control which are realized. Historical arable land use is roughly divided into three periods, which differ concerning the diversity of weed management and the occurring diversity in weed species. Obviously divers weed management in arable systems and diversity in weed species depend on each other, this is illustrated with a simple abstract picture. Arable systems, which are characterised by simpleness, favor the domination of few species which ensure an effective use of the resources within the ecosystem. One consequence under continuous pressure of an overused tool in weed management is that the genetic diversity within a dominating weed population is exploited to ensure this resource use. Current herbicides represent this tool – the results are herbicide resistant biotypes within the weed populations. Species diversity in arable weeds as a rationale within arable production can assist to prevent this development.

Weeds in a Changing Climate: Vulnerabilities, Consequences, and Implications for Future Weed Management.

Science.gov (United States)

Ramesh, Kulasekaran; Matloob, Amar; Aslam, Farhena; Florentine, Singarayer K; Chauhan, Bhagirath S

2017-01-01

Whilst it is agreed that climate change will impact on the long-term interactions between crops and weeds, the results of this impact are far from clear. We suggest that a thorough understanding of weed dominance and weed interactions, depending on crop and weed ecosystems and crop sequences in the ecosystem, will be the key determining factor for successful weed management. Indeed, we claim that recent changes observed throughout the world within the weed spectrum in different cropping systems which were ostensibly related to climate change, warrant a deeper examination of weed vulnerabilities before a full understanding is reached. For example, the uncontrolled establishment of weeds in crops leads to a mixed population, in terms of C 3 and C 4 pathways, and this poses a considerable level of complexity for weed management. There is a need to include all possible combinations of crops and weeds while studying the impact of climate change on crop-weed competitive interactions, since, from a weed management perspective, C 4 weeds would flourish in the increased temperature scenario and pose serious yield penalties. This is particularly alarming as a majority of the most competitive weeds are C 4 plants. Although CO 2 is considered as a main contributing factor for climate change, a few Australian studies have also predicted differing responses of weed species due to shifts in rainfall patterns. Reduced water availability, due to recurrent and unforeseen droughts, would alter the competitive balance between crops and some weed species, intensifying the crop-weed competition pressure. Although it is recognized that the weed pressure associated with climate change is a significant threat to crop production, either through increased temperatures, rainfall shift, and elevated CO 2 levels, the current knowledge of this effect is very sparse. A few models that have attempted to predict these interactions are discussed in this paper, since these models could play an

Ecological Weed Management by Cover Cropping: Effect on Winter Weeds and Summer Weeds Establishment in Potato

Directory of Open Access Journals (Sweden)

M Ghaffari

2012-07-01

Full Text Available Now a day winter cover crops planting has been attended to reduce herbicide application. An experiment was carried out at the Research Farm of Agriculture Faculty, Bu- Ali Sina, University, in 2009. The experiment was a randomized complete block design with three replications. The trial included of five treatments consists of no cover crop, rye, winter oilseed rape, barley and triticale. The results showed that winter cereals were produced more biomass than winter oilseed rape. living mulch of rye, barley, oilseed rape and triticale reduced winter weeds biomass 89, 86, 82 and 70 percent respectively, in compare to control. Cover crop treatments showed significant different weeds control of potato at 3 time (15, 45 and 75 DAPG compare to control treatment. Residues mixed to soil of oilseed rape and rye had the most inhibition affects on summer weeds. These treatments, average weeds biomass decreased 61 and 57 percent respectively, in compare to control. Oilseed rape and rye in compare to control reduced weeds density in potato 36 and 35 percent, respectively. Significant negation correlations of weeds plant population, weeds dry matter with average tuber weight and potato yield. The treatments, oilseed rape and rye in compare to control increased tuber yield of potato 54 and 50 percent, respectively. These treatments, the average tuber weight increased 74 and 38 percent in compare with control, respectively.

Non-chemical weed management

DEFF Research Database (Denmark)

Melander, Bo; Liebman, Matt; Davies, Adam S.

2017-01-01

Non-chemical weed management covers all management practices that influence weeds except herbicides. This chapter summarises the major achievements in European research, as well as work undertaken in North America. Research groups from both continents have interacted strongly on the topic over...... and in some cases amenity areas as well. Preventive methods reduce weed germination, cultural methods improve crop competition and direct physical weed control reduces weed survival. Non-chemical weed management is mainly adopted in organic crop production, as conventional growers still perceive it as more...

Site-specific weed control technologies

DEFF Research Database (Denmark)

Christensen, Svend; Søgaard, Henning Tangen; Kudsk, Per

2009-01-01

Site-specific weed control technologies are defined as machinery or equipment embedded with technologies that detect weeds growing in a crop and, taking into account predefined factors such as economics, takes action to maximise the chances of successfully controlling them. In the article, we...... describe the basic parts of site specific weed control technologies, comprising of weed sensing systems, weed management models and precision weed control implements. A review of state-of-the-art technologies shows that several weed sensing systems and precision implements have been developed over the last...... of knowledge about the economic and environmental potential for increasing the resolution of weed control. The integration of site-specific information on weed distribution, weed species composition and density, and the effect on crop yield, is decisive for successful site-specific weed management.   Keywords...

Effect of plant spacing and weeding frequency on weed infestation ...

African Journals Online (AJOL)

Common bean is an important food and cash crop in eastern Ethiopia. However, its yield is constrained by weeds. Therefore, this study was conducted in 2012 main cropping season at Haramaya and Hirna research fields, eastern Ethiopia, to determine the effect of plant spacing and weeding frequency on weeds, yield ...

Horny Goat Weed

Science.gov (United States)

Horny goat weed is an herb. The leaves are used to make medicine. As many as 15 horny goat weed species are known as “yin yang huo” in Chinese medicine. Horny goat weed is used for weak back and knees, ...

WeedML: a Tool for Collaborative Weed Demographic Modeling

OpenAIRE

Holst, Niels

2010-01-01

WeedML is a proposed standard to formulate models of weed demography, or maybe even complex models in general, that are both transparent and straightforward to re-use as building blocks for new models. The paper describes the design and thoughts behind WeedML which relies on XML and object-oriented systems development. Proof-of-concept software is provided as open-source C++ code and executables that can be downloaded freely.

Weeds in Organic Fertility-Building Leys: Aspects of Species Richness and Weed Management

Directory of Open Access Journals (Sweden)

Thomas F. Döring

2017-02-01

Full Text Available Legume-based leys (perennial sod crops are an important component of fertility management in organic rotations in many parts of Europe. Despite their importance, however, relatively little is known about how these leys affect weed communities or how the specific composition of leys may contribute to weed management. To determine whether the choice of plant species in the ley affects weeds, we conducted replicated field trials at six locations in the UK over 24 months, measuring weed cover and biomass in plots sown with monocultures of 12 legume and 4 grass species, and in plots sown with a mixture of 10 legume species and 4 grass species. Additionally, we monitored weed communities in leys on 21 organic farms across the UK either sown with a mixture of the project species or the farmers’ own species mix. In total, 63 weed species were found on the farms, with the annuals Stellaria media, Sonchus arvensis, and Veronica persica being the most frequent species in the first year after establishment of the ley, while Stellaria media and the two perennials Ranunculus repens and Taraxacum officinale dominated the weed spectrum in the second year. Our study shows that organic leys constitute an important element of farm biodiversity. In both replicated and on-farm trials, weed cover and species richness were significantly lower in the second year than in the first, owing to lower presence of annual weeds in year two. In monocultures, meadow pea (Lathyrus pratensis was a poor competitor against weeds, and a significant increase in the proportion of weed biomass was observed over time, due to poor recovery of meadow pea after mowing. For red clover (Trifolium pratense, we observed the lowest proportion of weed biomass in total biomass among the tested legume species. Crop biomass and weed biomass were negatively correlated across species. Residuals from the linear regression between crop biomass and weed biomass indicated that at similar levels of crop

1-14 Effect of Plant Spacing and Weeding Frequency on Weed ...

African Journals Online (AJOL)

user

2College of Agriculture and Environmental Sciences, Haramaya University, ... pod, hundred seed weight, grain yield, aboveground dry biomass, and ... an infestation by weeds and the performance of crop ... frequencies affect weed management in common bean .... including broad-leaved, sedge and grass weeds (Table.

Effect of Cultural Practices in Night on Weed Density and Weed Dry Matter

Directory of Open Access Journals (Sweden)

M.H Rashed Mohasel

2011-01-01

Full Text Available Abstract In order to evaluate the response of weed seeds to light, two experiments, at two different locations were conducted at Ferdowsi university of Mashhad in 2009. At the first experiment, field was ploughed in day and night. Weed density was evaluated 70 d after plough, with 1×1 quadrate. At the second experiment, at night treatment, ploughing, potato planting and weeding with cultivator were done at night. Weed sampling was done twice at 43 and 130 days after planting with 1×1 quadrate and weeds were identified and counted. Result showed pigweed (Amaranthus retroflexus L., sowthistle (Sonchus oleraceus L., crabgrass (Digitaria sanguinalis (L. scop, jimsonweed (Datura stramonium L. and mallow (Hibiscus trionum L. did not observed at night plough, in contrast, night plough has no significance influence on common lambsquarters (Chenopodium album L., and black nightshade (Solanum nigrum L.. Only common lambsquarters had similar appearance in two treatments, indicating insusceptibility of this weed to time of plough. Interestingly, at the second experiment, result was very similar. Potato yield was higher at night treatment, but not significant. This research showed that some cultural practice like plough, planting and weeding with cultivator in night can reduce weed density and weed dry matter. Keywords: Germination, Time of plough, Sustainable weeds management, Light

Current glimpse of airborne allergenic pollen in Indian subcontinent

Directory of Open Access Journals (Sweden)

Kavita Ghosal

2015-12-01

Full Text Available Respiratory allergic diseases such as bronchial asthma, rhinitis, urticaria, atopic dermatitis have been steadily increasing all over the world, including India. Owing to its alarming trend, several aerobiological surveys have been undertaken in different parts of India to delineate the variety of pollen and spore load. In this review, we have reported the current state of aerobiological knowladge in India with particular reference to allergenic airborn pollen occurence in 2001–2015. Pollen have been found to contribute a significant proportion in the air and caused allergy symptoms in the local inhabitants. Aerobiological records, a questionnaire survey and hospitalization records have been employed for the analysis. Holoptelea integrifolia, Amaranthus spinosus in northern region, Sorghum vulgare, Pennisetum, Gynandropsis gynandra, Parthenium hysterophorus, Dolichandrone platycalyx in southern regions, and Parthenium hysterophorus from the western region; Cynodon dactylon, Cenchrus ciliaris in the central area; Acacia auriculiformis, Cleome gynandra, Catharanthus roseus, Phoenix sylvestris, Areca catechu, and Lantana camara in the eastern regions as potential aeroallergens in India. The statistical approach confirmed the correlation between hospitalization rate associated with allergy-related health troubles and the prevalent allergenic pollen in the air. The Poaceae group has been found to be dominant throughout India. Immuno-biochemical studies identified various protein with allergenic potential found in the pollen recorded. Epitope identification and homology of the major allergenic protein Cat r1 of Catharanthus sp and Par j 1 of Parietaria judaica have been found. Identification of allergenic pollen grains and the modern approach concerning cross-reactivity and epitope revelation of dominant airborne pollen have important clinical implications for the prevention, diagnosis and treatments of allergic diseases in India.

Effects of medicinal plant extracts on growth of Leishmania (L. amazonensis and Trypanosoma cruzi Efeito de extratos de plantas medicinais no crescimento de Leishmania (L. amazonensis e Trypanosoma cruzi

Directory of Open Access Journals (Sweden)

Patrícia Shima Luize

2005-03-01

Full Text Available This study describes the screening of extracts obtained from 19 species of plants used in Brazilian traditional medicine for treatment of a variety of diseases. The extracts were tested against axenic amastigote and promastigote forms of Leishmania (L. amazonensis, and epimastigote forms of Trypanosoma cruzi in vitro at a concentration of 100 mg/ml. Baccharis trimera, Cymbopogon citratus, Matricaria chamomilla, Mikania glomerata, Ocimum gratissimum, Piper regnellii, Prunus domestica, Psidium guajava, Sambucus canadensis, Stryphnodendron adstringens, Tanacetum parthenium, and Tanacetum vulgare showed significant effects against one or both parasites, with a percentage of growth inhibition between 49.5 and 99%. The extracts showed no cytotoxic effect on sheep erythrocytes. These medicinal plants may be sources of new compounds that are clinically active against L. amazonensis and T. cruzi.Este estudo descreve a triagem de extratos obtidos de 19 espécies de plantas usadas na medicina tradicional brasileira para o tratamento de várias doenças. Os extratos foram testados contra formas amastigota axênica e promastigota de Leishmania (L. amazonensis, e formas epimastigota de Trypanosoma cruzi in vitro na concentração de 100 mg/ml. Baccharis trimera, Cymbopogon citratus, Matricaria chamomilla, Mikania glomerata, Ocimum gratissimum, Piper regnellii, Prunus domestica, Psidium guajava, Sambucus canadensis, Stryphnodendron adstringens, Tanacetum parthenium, e Tanacetum vulgare apresentaram efeito significante contra um ou ambos parasitas, com a porcentagem de inibição de crescimento entre 49,5 e 99%. Os extratos não mostraram efeito citotóxico em hemácias de carneiro. Essas plantas medicinais podem ser fontes alternativas de novos compostos clinicamente ativos contra L. amazonensis e T. cruzi.

Effect of Weed Management on Weeds and Grain Yield of Haricot ...

African Journals Online (AJOL)

Weeds are one of the major constraints limiting haricot bean productivity and production. Field experiments were conducted on the effect of weed managements on weeds and grain yield of haricot bean (Phaseolus Vulgaris L.) at Melkassa Agricultural Research Center from 2011 - 2013. The objective was to determine the ...

Ecologically sustainable weed management

DEFF Research Database (Denmark)

Liebman, Matt; Baraibar, Bàrbara; Buckley, Yvonne

2016-01-01

Weed management is a critically important activity on both agricultural and non-agricultural lands, but it is faced with a daunting set of challenges: environmental damage caused by control practices, weed resistance to herbicides, accelerated rates of weed dispersal through global trade, and gre......Weed management is a critically important activity on both agricultural and non-agricultural lands, but it is faced with a daunting set of challenges: environmental damage caused by control practices, weed resistance to herbicides, accelerated rates of weed dispersal through global trade...... to influence learning, decision-making, and actions by farmers and land managers. We offer examples of how these impediments are being addressed in different parts of the world, but note that there is no clear formula for determining which sets of policies, market mechanisms, and educational activities...... will be effective in various locations. Implementing new approaches for weed management will require multidisciplinary teams comprised of scientists, engineers, economists, sociologists, educators, farmers, land managers, industry personnel, policy makers, and others willing to focus on weeds within whole farming...

Seed characters and their usefulness in the separation of Asteraceae species

Directory of Open Access Journals (Sweden)

Michelli Fernandes Batista

2015-10-01

Full Text Available Studies on seed structure of Asteraceae have received little attention of botanists. Seed structure in Asteraceae is analyzed to evaluate the usefulness of characters in the separation of species through the analysis of nine weedy species. Seeds originate from anatropous, unitegmic and tenuinucellate ovules. The partial collapse of the developing seed coat is a common characteristic in the Asteraceae species studied. The testa consists of crushed and thin-walled cells in almost all of the species studied herein, except for Elephantopus mollis and Parthenium hysterophorus, which showed exotesta cells with U-shaped thickening. The analysis revealed high uniformity in seed characters.

Weed clearance in Hudiara Nallah by chemical weed control

International Nuclear Information System (INIS)

Dhillon, G.S.

1981-01-01

Hudiara Nallah is a flood stream in West Punjab. It has a length of about 45km and breadth of nearly 25 metres. About 20 subsidiary drains join with the Nallah. These drains have a length of about 270km. The Nallah has a discharge capacity of 1248 cusecs. Most of the subsidiary drains start from ponds which are generally infected with Eichhornia plants. These plants enter into the subsidiary drains and finally into Hudiara Nallah. The plants float freely on the surface of water and multiply at a high rate. One plant of the weed propagates to 24 plants in a period of one month. The plants thus cover the whole drain in a few months. The weed also originates from seeds. Their heavy growth forms a mat-like surface. The weeds also choke bridges and sometimes cause damage to their structures. These obstruct the flow of water and decrease the carrying capacity of the drain. Their infestation thus causes floods and the very purpose of the drains gets lost. Thus the Nallah is heavily infested with Eichhornia crassipes (water hyacinth weed). Due to its fast propagation and heavy infestation it was not possible to clear the weed manually. The problem was, therefore, referred to the Chemistry Division of the Irrigation and Power Research Institute, Amritsar, by the Drainage Circle of the Irrigation Department in June 1978 when weed propagation was in full swing. A chemical treatment method of eradication was attempted

Linking Farmer Weed Management Behavior with Weed Pressure: More than Just Technology

NARCIS (Netherlands)

Riemens, M.M.; Groeneveld, R.M.W.; Kropff, M.J.; Lotz, L.A.P.; Renes, R.J.; Sukkel, W.; Weide, van der R.Y.

2010-01-01

Most studies on weed population dynamics in farming systems have focused on the effects of different weed control strategies. Those studies usually assume that farmers, operating within a particular system, have a uniform management style. However, it is likely that weed management decision making

WEED INTERFERENCE IN EGGPLANT CROPS

Directory of Open Access Journals (Sweden)

LUIZ JUNIOR PEREIRA MARQUES

2017-01-01

Full Text Available Uncontrolled weed growth interferes with the growth eggplants and crop yields. To control weeds, the main weed species must be identified in crop growing areas and during weed control periods, as weed species might vary in relation to management practices. Therefore, this study aimed to identify the main weed species and determine the periods of weed interference in the eggplant cultivar Nápoli when grown under certain cultural practices, including plant staking and sprout thinning. The experiment was carried out in 2014 using a randomized complete block design, with 3 replications. The treatments consisted of 11 periods of (1 increasing weed control and (2 increasing coexistence of eggplant with weeds from the first day of transplanting (0-14, 0-28, 0-42, 0-56, 0-70, 0-84, 0-98, 0-112, 0-126, 0-140, and up do day 154. Eggplant staking and sprout thinning were performed 42 days after transplanting (DAT. Weed identification and crop yield assessments were performed to determine the Period Before Interference (PBI, Total Period of Interference Prevention (TPIP, and the Critical Period of Interference Prevention (CPIP. The major weeds found in the eggplant cultivar Nápoli were Eleusine indica, Portulaca oleracea, and Cyperus rotundus. Coexistence between the weed community and the eggplant throughout the entire crop production cycle reduced eggplant fruit yield by 78%. The PBI was 29 DAT and the TPIP was 48 DAT, resulting in 19 days of CPIP.

Effect of weed management on weeds and grain yield of haricot bean

African Journals Online (AJOL)

Weeds are one of the major constraints limiting haricot bean productivity and production. Field experiments were conducted on the effect of weed managements on weeds and grain yield of haricot bean (Phaseolus Vulgaris L.) at Melkassa Agricultural Research Center from 2011 - 2013. The objective was to determine the ...

INTEGRATED WEED CONTROL IN MAIZE.

Science.gov (United States)

Latré, J; Dewitte, K; Derycke, V; De Roo, B; Haesaert, G

2015-01-01

Integrated pest management has been implemented as a general practice by EU legislation. As weed control actually is the most important crop protection measure in maize for Western Europe, the new legislation will have its impact. The question is of course which systems can be successfully implemented in practice with respect to labour efficiency and economical parameters. During 3 successive growing seasons (2007, 2008, 2009) weed control in maize was evaluated, the main focus was put on different techniques of integrated weed control and was compared with chemical weed control. Additionally, during 4 successive growing seasons (2011, 2012, 2013 and 2014) two objects based on integrated weed control and two objects based on mechanical weed control were compared to about twenty different objects of conventional chemical weed control. One of the objects based on mechanical weed control consisted of treatment with the flex-tine harrow before and after emergence in combination with chemical weed control at a reduced rate in 3-4 leave stage. The second one consisted of broadcast mechanical treatments before and after emergence followed by a final in-row application of herbicides and an inter-row cultivation at 6-7(8) leave stage. All trials were conducted on the Experimental farm of Bottelare HoGent-UGent on a sandy loam soil. Maize was growing in 1/3 crop rotation. The effect on weed growth as well as the economic impact of the different applications was evaluated. Combining chemical and mechanical weed control is a possible option in conventional farming but the disadvantages must be taken into account. A better planned weed control based on the real present weed-population in combination with a carefully thought-out choice of herbicides should also be considered as an IPM--approach.

Elucidation of the sesquiterpene lactone biosynthetic pathway in feverfew (Tanacetum parthenium)

OpenAIRE

Liu, Q.

2013-01-01

Parthenolide is the major bioactive compound of feverfew and has anti-inflammatory and anti-cancer activity. Chapter 1gives an overview of the history and current status of research on parthenolide in feverfew. As a promising anti-cancer drug, parthenolide has attracted a lot of attention from medical institutes and companies. A search with ‘parthenolide’ in Google patents yields more than 2000 hits on extraction of parthenolide or its use in treating cancer or other diseases. However, infor...

Elucidation of the sesquiterpene lactone biosynthetic pathway in feverfew (Tanacetum parthenium)

NARCIS (Netherlands)

Liu, Q.

2013-01-01

Parthenolide is the major bioactive compound of feverfew and has anti-inflammatory and anti-cancer activity. Chapter 1gives an overview of the history and current status of research on parthenolide in feverfew. As a promising anti-cancer drug, parthenolide has attracted a lot of

Weed ecology and population dynamics

Science.gov (United States)

A global rise in herbicide resistant weed genotypes, coupled with a growing demand for food produced with minimal external synthetic inputs, is driving producer interest in reducing reliance on herbicides for weed management. An improved understanding of weed ecology can support the design of weed s...

Population dynamics of weeds in oil palm (Elaeis guineensis Jacq.) circle weeding area affected by herbicide application

Science.gov (United States)

Sidik, S.; Purba, E.; Yakub, E. N.

2018-02-01

Weed problems in oil palm field were mainly overcomed by herbicide application. The application certain herbicides may lead to rapid population dynamic of certain species due to their different response to herbicides. Some species may less susceptible to certain herbicide whereas other species more susceptible. The objective of this study was to determine the population dynamic of weed species in circle weeding of oil palm in Serdang Bedagai, North Sumatra. Six treatments using glyphosate singly and mixture compared with manual weeding were evaluated for weed control. The treatments were arranged in a randomized block design with four replicates. Each treatment consisted of four circle weedings. The results showed that glyphosate 720 g a.i/ha + indaziflam 50 g a.i/hareduced seedbank and regrowth of weeds. Up to 12 weeks after application glyphosate 720 g a.i/ha + indaziflam 50 g a.i/ha is 29.46% total weeds dry weight compared to manual weeding. The effect of herbicide application on changes on the weed composition and weed seedbank are affected by the characteristic of herbicides and weed response to herbicide application.

Ecologically sustainable weed management

NARCIS (Netherlands)

Liebman, Matt; Baraibar, Bàrbara; Buckley, Yvonne; Childs, Dylan; Christensen, Svend; Cousens, Roger; Eizenberg, Hanan; Heijting, Sanne; Loddo, Donato; Merotto, Aldo; Renton, Michael; Riemens, Marleen

2016-01-01

Weed management is a critically important activity on both agricultural and non-agricultural lands, but it is faced with a daunting set of challenges: environmental damage caused by control practices, weed resistance to herbicides, accelerated rates of weed dispersal through global trade, and

Weeds of onion fields and effects of some herbicides on weeds in ...

African Journals Online (AJOL)

Weeds are one of the most important problems in onion (Allium cepa L.) production areas, since onion plants are poor competitors. This study was conducted in order to identify the weed species in onion fields in Cukurova Region, establish the effects of some herbicides on weeds and the yield of onion in reducing the ...

Investigating a Potential Auxin-Related Mode of Hormetic/Inhibitory Action of the Phytotoxin Parthenin.

Science.gov (United States)

Belz, Regina G

2016-01-01

Parthenin is a metabolite of Parthenium hysterophorus and is believed to contribute to the weed's invasiveness via allelopathy. Despite the potential of parthenin to suppress competitors, low doses stimulate plant growth. This biphasic action was hypothesized to be auxin-like and, therefore, an auxin-related mode of parthenin action was investigated using two approaches: joint action experiments with Lactuca sativa, and dose-response experiments with auxin/antiauxin-resistant Arabidopsis thaliana genotypes. The joint action approach comprised binary mixtures of subinhibitory doses of the auxin 3-indoleacetic acid (IAA) mixed with parthenin or one of three reference compounds [indole-3-butyric acid (IBA), 2,3,5-triiodobenzoic acid (TIBA), 2-(p-chlorophenoxy)-2-methylpropionic acid (PCIB)]. The reference compounds significantly interacted with IAA at all doses, but parthenin interacted only at low doses indicating that parthenin hormesis may be auxin-related, in contrast to its inhibitory action. The genetic approach investigated the response of four auxin/antiauxin-resistant mutants and a wildtype to parthenin or two reference compounds (IAA, PCIB). The responses of mutant plants to the reference compounds confirmed previous reports, but differed from the responses observed for parthenin. Parthenin stimulated and inhibited all mutants independent of resistance. This provided no indication for an auxin-related action of parthenin. Therefore, the hypothesis of an auxin-related inhibitory action of parthenin was rejected in two independent experimental approaches, while the hypothesis of an auxin-related stimulatory effect could not be rejected.

WEED SURVEYING OF PHACELIA (PHACELIA TANACETIFOLIA L.) AND EVALUATING THE EFFICIENCY OF THE WEED CONTROL.

Science.gov (United States)

Horváth, E; Szabó, R

2014-01-01

The experiment was set up in an area of 9 ha that was split into 4 plots: in plot 1 the row spacing was 12 cm and the seeding rate was 10 kg; in plot 2 the row spacing was 24 cm and the seeding rate was 10 kg; in plot 3 the row spacing was 24 cm and the seeding rate was 8 kg; in plot 4 the row spacing was 12 cm and the seeding rate was 8 kg. After the weed surveying, the total weed coverage was established as follows: in plot 1 the total weed coverage was 11.34%, in plot 2 it was 12.3%, in plot 3 it was 18%, and in plot 4 the total weed coverage was 15%. Based on the weed survey, on the test area the following dicotyledon weeds belonging to the T4 Raunkiaer plant life-form category occupied the highest percentage: heal-all, black-bindweed, goosefoot. The proportion of the perennial dicotyledons: field bindweed (G3), tuberous pea (G1), white campion (H3) was negligible. In all four cases the weed control was executed using the same herbicide in the same doses and with regard to the weed species it showed the same level of efficiency. The smaller row spacing and higher seeding rate has a beneficial effect on the weed suppressing capacity of the crop, the crop's weed suppressing capacity is better and the development of the weeds becomes worse.

Can global weed assemblages be used to predict future weeds?

Directory of Open Access Journals (Sweden)

Louise Morin

Full Text Available Predicting which plant taxa are more likely to become weeds in a region presents significant challenges to both researchers and government agencies. Often it is done in a qualitative or semi-quantitative way. In this study, we explored the potential of using the quantitative self-organising map (SOM approach to analyse global weed assemblages and estimate likelihoods of plant taxa becoming weeds before and after they have been moved to a new region. The SOM approach examines plant taxa associations by analysing where a taxon is recorded as a weed and what other taxa are recorded as weeds in those regions. The dataset analysed was extracted from a pre-existing, extensive worldwide database of plant taxa recorded as weeds or other related status and, following reformatting, included 187 regions and 6690 plant taxa. To assess the value of the SOM approach we selected Australia as a case study. We found that the key and most important limitation in using such analytical approach lies with the dataset used. The classification of a taxon as a weed in the literature is not often based on actual data that document the economic, environmental and/or social impact of the taxon, but mostly based on human perceptions that the taxon is troublesome or simply not wanted in a particular situation. The adoption of consistent and objective criteria that incorporate a standardized approach for impact assessment of plant taxa will be necessary to develop a new global database suitable to make predictions regarding weediness using methods like SOM. It may however, be more realistic to opt for a classification system that focuses on the invasive characteristics of plant taxa without any inference to impacts, which to be defined would require some level of research to avoid bias from human perceptions and value systems.

Ecological Intensification Through Pesticide Reduction: Weed Control, Weed Biodiversity and Sustainability in Arable Farming.

Science.gov (United States)

Petit, Sandrine; Munier-Jolain, Nicolas; Bretagnolle, Vincent; Bockstaller, Christian; Gaba, Sabrina; Cordeau, Stéphane; Lechenet, Martin; Mézière, Delphine; Colbach, Nathalie

2015-11-01

Amongst the biodiversity components of agriculture, weeds are an interesting model for exploring management options relying on the principle of ecological intensification in arable farming. Weeds can cause severe crop yield losses, contribute to farmland functional biodiversity and are strongly associated with the generic issue of pesticide use. In this paper, we address the impacts of herbicide reduction following a causal framework starting with herbicide reduction and triggering changes in (i) the management options required to control weeds, (ii) the weed communities and functions they provide and (iii) the overall performance and sustainability of the implemented land management options. The three components of this framework were analysed in a multidisciplinary project that was conducted on 55 experimental and farmer's fields that included conventional, integrated and organic cropping systems. Our results indicate that the reduction of herbicide use is not antagonistic with crop production, provided that alternative practices are put into place. Herbicide reduction and associated land management modified the composition of in-field weed communities and thus the functions of weeds related to biodiversity and production. Through a long-term simulation of weed communities based on alternative (?) cropping systems, some specific management pathways were identified that delivered high biodiversity gains and limited the negative impacts of weeds on crop production. Finally, the multi-criteria assessment of the environmental, economic and societal sustainability of the 55 systems suggests that integrated weed management systems fared better than their conventional and organic counterparts. These outcomes suggest that sustainable management could possibly be achieved through changes in weed management, along a pathway starting with herbicide reduction.

Weed Dynamics and Management in Wheat

DEFF Research Database (Denmark)

Jabran, Khawar; Mahmood, Khalid; Melander, Bo

2017-01-01

) chemical weed control; and (vi) integrated weed management strategy in wheat. A critical analysis of recent literature indicated that broadleaved weeds are the most common group of weeds in wheat fields followed by grass weeds, while sedges were rarely noted in wheat fields. Across the globe, the most...

Selective weed control using laser techniques

OpenAIRE

Marx, Christian; Pastrana-Perez, Julio; Hustedt, Michael; Barcikowski, Stephan; Haferkamp, Heinz; Rath, Thomas

2012-01-01

This contribution discusses technical and growth relevant aspects of using laser techniques for weed control. The research on thermal weed control via laser first focused on the interaction of laser beams and weed plants. Due to preliminary studies, a CO2-laser was selected for further studies with regard to the process factors laser energy, laser spot area, coverage of the weeds meristem, weed species (Amaranthus retroflexus), and weed growth stage. Thereby, the laser damage was modeled in o...

SHIFTING WEED COMPOSITIONS AND BIOMASS PRODUCTION IN SWEET CORN FIELD TREATED WITH ORGANIC COMPOSTS AND CHEMICAL WEED CONTROLS

Directory of Open Access Journals (Sweden)

Marulak Simarmata

2015-10-01

Full Text Available The objectives of the research were to study the shift of weed compositions in sweet corn field treated with organic compost and chemical weed controls and to compare the effect of treatment combinations on weed growth, weed biomass and sweet corn biomass. The research was conducted in Bengkulu, Indonesia, from April to July 2014. Results showed that the number of weed species decreased after the trials from 14 to 13. There was a shift in weed compositions because 5 species of weeds did not emerge after the trials, but 4 new species were found. Chemical weed control used a herbiside mixture of atrazine and mesotrione applied during postemergence was the most effective method to control weeds, which was observed on decreased weed emergence and weed biomass down to 22.33 and 25.00 percent of control, respectively. Subsequently, biomass production of sweet corn increased up to 195.64 percent at the same trials. Biomass of weeds and sweet corn were also affected by the organic composts. Weed biomass was inhibited by treatment of composted empty fruith bunches of oil palm, whereas significantly increased of sweet corn biomass were observed in the plots of organic manure.

Weed infestation of spring barley (Hordeum vulgare L. depending on the cover crop and weed control method

Directory of Open Access Journals (Sweden)

Dorota Gawęda

2014-04-01

Full Text Available The aim of this 3-year field study was to evaluate the effect of some stubble crops and weed control methods on the species composition, number and air-dry weight of weeds in a spring barley crop grown in short-term monoculture. The study was conducted in the period 2009–2011 at the Uhrusk Experimental Farm, on mixed rendzina soil classified as very good rye soil complex. It included stubble crops which were ploughed under in each year (control treatment without cover crop, white mustard, lacy phacelia, a mixture of legumes – narrow-leaf lupin + field pea and 3 weed control methods used in spring barley crops (mechanical, mechanical and chemical, chemical weed control. Veronica persica was the weed species that occurred in greatest numbers in the spring barley crop sown after stubble crops. All cover crops reduced the numbers of Avena fatua which was the dominant species in the control treatment. Chemical as well as chemical and mechanical weed control significantly reduced the numbers of Avena fatua compared to the treatment where only double harrowing was used for weed control. The stubble crops did not reduce weed infestation of spring barley. Compared to the control treatment, the ploughing-in of white mustard and the mixture of legumes reduced the dry weight of weeds by 49.1 and 22.7%, respectively. Mechanical weed management proved to be less effective in reducing the number and dry weight of weeds compared to the other weed control methods. A significant negative correlation was found between the dry weight of weeds in the spring barley crop and the dry weight of the ploughed-in white mustard cover crop under the conditions of chemical weed control as well as in the case of the mixture of legumes when complete mechanical and chemical weed control was used.

Weed Control in Soybean (Glycine max)

International Nuclear Information System (INIS)

Kipkemoi, P.L.

2002-01-01

Weed Compete for limited growth factors with crop plants. This result in loss of crop vigour and hence reduces crop yields. A study was conducted in 1997 and 2001 to evaluate the use of herbicides and hand hoeing for weed control in soybeans. Crop establishment was by hand planting. The herbicides were applied using CP3 Knap sack sprayer calibrated to deliver a spray volume of 150l/ha. Hand weeding treatment were done as appropriate. The trial layout was randomised complete block design with four replications in both years. The tested herbicides did not satisfactorily control the weeds present at the experimental site in both years. Hand weeding on the other hand gave good control of the weeds which were reflected in high soybean yields. In these trials yields were negatively correlated with the number of weeds present. The tested herbicides alone appeared to be inadequate in controlling weeds in soybean. Compared with the weed-free treatment a single application of soil-applied or post-emergence herbicides did not control a broad spectrum of weeds and reduced soybean yields. It can also be inferred that soybean yield losses are minimised if they are kept weed free for at most 6 weeks after emergence

Ecological weed management by cover cropping : effects on weed growth in autumn and weed establishment in spring

NARCIS (Netherlands)

Kruidhof, H.M.; Bastiaans, L.; Kropff, M.J.

2008-01-01

Cover crops grown in the period between two main crops have potential as an important component of a system-oriented ecological weed management strategy. In late summer and autumn, the cover crop can suppress growth and seed production of weeds, whereas the incorporation of cover crop residues in

Biological weed control with soil fungi? Antagonistic effects of arbuscular mycorrhizal fungi on the growth of weeds

NARCIS (Netherlands)

Veiga, R.

2012-01-01

Excessive weed growth represents one of the major threats to crop production especially when reliance on herbicides is reduced. Biological weed control is an alternative, environmentally-sound method that, combined with other weed control practices, can contribute to an effective weed management in

7 CFR 201.15 - Weed seeds.

Science.gov (United States)

2010-01-01

... 7 Agriculture 3 2010-01-01 2010-01-01 false Weed seeds. 201.15 Section 201.15 Agriculture... REGULATIONS Labeling Agricultural Seeds § 201.15 Weed seeds. The percentage of weed seeds shall include seeds of plants considered weeds in the State into which the seed is offered for transportation or...

RNAseq reveals weed-induced PIF3-like as a candidate target to manipulate weed stress response in soybean.

Science.gov (United States)

Horvath, David P; Hansen, Stephanie A; Moriles-Miller, Janet P; Pierik, Ronald; Yan, Changhui; Clay, David E; Scheffler, Brian; Clay, Sharon A

2015-07-01

Weeds reduce yield in soybeans (Glycine max) through incompletely defined mechanisms. The effects of weeds on the soybean transcriptome were evaluated in field conditions during four separate growing seasons. RNASeq data were collected from six biological samples of soybeans growing with or without weeds. Weed species and the methods to maintain weed-free controls varied between years to mitigate treatment effects, and to allow detection of general soybean weed responses. Soybean plants were not visibly nutrient- or water-stressed. We identified 55 consistently downregulated genes in weedy plots. Many of the downregulated genes were heat shock genes. Fourteen genes were consistently upregulated. Several transcription factors including a PHYTOCHROME INTERACTING FACTOR 3-like gene (PIF3) were included among the upregulated genes. Gene set enrichment analysis indicated roles for increased oxidative stress and jasmonic acid signaling responses during weed stress. The relationship of this weed-induced PIF3 gene to genes involved in shade avoidance responses in Arabidopsis provide evidence that this gene may be important in the response of soybean to weeds. These results suggest that the weed-induced PIF3 gene will be a target for manipulating weed tolerance in soybean. No claim to original US government works New Phytologist © 2015 New Phytologist Trust.

Weed Identification and Control in Vegetable Crops.

Science.gov (United States)

Ferretti, Peter A., Comp.

This agriculture extension service publication from Pennsylvania State University examines weed control and identification in vegetable crops. Contents include: (1) Types of weeds; (2) Reducing losses caused by weeds, general control methods and home garden weed control; (3) How herbicides are used; (4) Specific weeds in vegetable plantings; and…

Combining a weed traits database with a population dynamics model predicts shifts in weed communities

DEFF Research Database (Denmark)

Storkey, Jonathan; Holst, Niels; Bøjer, Ole Mission

2015-01-01

A functional approach to predicting shifts in weed floras in response to management or environmental change requires the combination of data on weed traits with analytical frameworks that capture the filtering effect of selection pressures on traits. A weed traits database (WTDB) was designed, po...

Combining a weed traits database with a population dynamics model predicts shifts in weed communities.

Science.gov (United States)

Storkey, J; Holst, N; Bøjer, O Q; Bigongiali, F; Bocci, G; Colbach, N; Dorner, Z; Riemens, M M; Sartorato, I; Sønderskov, M; Verschwele, A

2015-04-01

A functional approach to predicting shifts in weed floras in response to management or environmental change requires the combination of data on weed traits with analytical frameworks that capture the filtering effect of selection pressures on traits. A weed traits database (WTDB) was designed, populated and analysed, initially using data for 19 common European weeds, to begin to consolidate trait data in a single repository. The initial choice of traits was driven by the requirements of empirical models of weed population dynamics to identify correlations between traits and model parameters. These relationships were used to build a generic model, operating at the level of functional traits, to simulate the impact of increasing herbicide and fertiliser use on virtual weeds along gradients of seed weight and maximum height. The model generated 'fitness contours' (defined as population growth rates) within this trait space in different scenarios, onto which two sets of weed species, defined as common or declining in the UK, were mapped. The effect of increasing inputs on the weed flora was successfully simulated; 77% of common species were predicted to have stable or increasing populations under high fertiliser and herbicide use, in contrast with only 29% of the species that have declined. Future development of the WTDB will aim to increase the number of species covered, incorporate a wider range of traits and analyse intraspecific variability under contrasting management and environments.

Effect of ploughing frequency and weeding methods on weeds and ...

African Journals Online (AJOL)

User

Five tillage practices ... 2.5 l ha-1, Duplosan plus one hand weeding at 30 days after emergence (DAE); ... weed on time, is one of the major constraints in wheat ... management factors and soil type (Yohannes, 1982). .... The finding at ICARDA (1984) shows that ..... selling price of the crop changes, the farmer can still get a.

Overview of glyphosate-resistant weeds worldwide.

Science.gov (United States)

Heap, Ian; Duke, Stephen O

2018-05-01

Glyphosate is the most widely used and successful herbicide discovered to date, but its utility is now threatened by the occurrence of several glyphosate-resistant weed species. Glyphosate resistance first appeared in Lolium rigidum in an apple orchard in Australia in 1996, ironically the year that the first glyphosate-resistant crop (soybean) was introduced in the USA. Thirty-eight weed species have now evolved resistance to glyphosate, distributed across 37 countries and in 34 different crops and six non-crop situations. Although glyphosate-resistant weeds have been identified in orchards, vineyards, plantations, cereals, fallow and non-crop situations, it is the glyphosate-resistant weeds in glyphosate-resistant crop systems that dominate the area infested and growing economic impact. Glyphosate-resistant weeds present the greatest threat to sustained weed control in major agronomic crops because this herbicide is used to control weeds with resistance to herbicides with other sites of action, and no new herbicide sites of action have been introduced for over 30 years. Industry has responded by developing herbicide resistance traits in major crops that allow existing herbicides to be used in a new way. However, over reliance on these traits will result in multiple-resistance in weeds. Weed control in major crops is at a precarious point, where we must maintain the utility of the herbicides we have until we can transition to new weed management technologies. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Weed control in rose-scented geranium (Pelargonium spp).

Science.gov (United States)

Kothari, Sushil K; Singh, Chandra P; Singh, Kamla

2002-12-01

Abstract: Field investigations were carried out during 1999 and 2000 to identify effective chemical/ cultural methods of weed control in rose-scented geranium (Pelargonium spp). The treatments comprised pre-emergence applications of oxyfluorfen (0.15, 0.20 and 0.25 kg AI ha(-1)) and pendimethalin (0.50, 0.75 and 1.00kg AI ha(-1)), successive hand weeding, hoeing and mulching using spent of lemon grass (at 5 tonnes ha(-1)) 45 days after planting (DAP), three hand-weedings 30, 60 and 90 DAP, weed-free (frequent manual weeding) and weedy control. Broad-leaf weeds were more predominant than grass and sedge weeds, accounting for 85.8% weed density and 93.0% weed dry weight in 1999 and 77.2% weed density and 93.9% weed dry weight in 2000. Unrestricted weed growth significantly reduced geranium oil yield, by 61.6% and 70.6% in 1999 and 2000, respectively. Pre-emergence application of pendimethalin (0.75-1.00 kgAI ha(-1)) or oxyfluorfen (0.25 kg AI ha(-1)), successive hand-weeding, hoeing and mulching and three hand-weedings were highly effective in reducing weed density and dry weight and gave oil yield comparable to the weed-free check. Application of oxyfluorfen (0.15 or 0.20 kg AI ha(-1)) and pendimethalin (0.50 kg AI ha(-1)) were less effective in controlling the weed species in geranium. None of the herbicides impaired the quality of rose-scented geranium oil measured in terms of citronellol and geraniol content.

The effect of sowing strategy, row distance and mechanical weed control on weeds and yield in organic winter wheat

OpenAIRE

Rasmussen, Ilse A.

2002-01-01

A series of field experiments were carried out in winter wheat grown under organic conditions in Denmark on fields with different weed pressure. The treatments were sowing strategy (normal sowing time, late sowing and false seedbed), row distance (12 cm and 24 cm row distance) and weed control method (untreated, mechanical weed control (weed harrowing at 12 cm supplemented with row hoeing at 24 cm), and herbicide weed control). Weed biomass was largest at the normal sowing time and was reduce...

Changes in weed infestation of common bean (Phaseolus vulgaris L. under conditions of strip intercropping and different weed control methods

Directory of Open Access Journals (Sweden)

Aleksandra Głowacka

2012-12-01

Full Text Available The experiment was conducted in the years 2004-2006 in a private farm in the village of Frankamionka in Zamość district. There were two experimental factors: I. Cultivation methods - sole cropping and strip intercropping; and II. Tending methods - mechanical, mechanical-chemical, and chemical weed control. The subject of the study was weed infestation of the Mela variety of common bean. Beans were sown between 30 April and 5 May. Weed infestation was assessed in the last week before harvesting by determining its floristic composition and the frequency of occurrence of particular weed species, as well as the air-dry weight of weeds. The dominant weed species were Galinsoga parviflora, Echinochloa crus-galli, Chenopodium album, and Amaranthus retroflexus, which comprised 84.7% of the total number of weeds. Strip intercropping markedly reduced the number of weeds per unit area (by 50%, as well as the dry weight of their aerial parts. The most effective method of weed control was the mechanical-chemical method, which resulted in the lowest occurrence of weeds. It also significantly reduced the weight of weeds.

Determining treatment frequency for controlling weeds on traffic islands using chemical and non-chemical weed control

DEFF Research Database (Denmark)

Rask, Anne Merete; Larsen, S.U.; Andreasen, Christian

2013-01-01

Many public authorities rely on the use of non-chemical weed control methods, due to stringent restrictions on herbicide use in urban areas. However, these methods usually require more repeated treatments than chemical weed management, resulting in increased costs of weed management. In order...... of treatments per year were required: glyphosate 2.5, hot water 3, flames 5, hot air/flames 5.5 and steam 5.5 treatments. The results demonstrate that the weed control should be adjusted to the prescribed quality for the traffic islands by regularly assessing the need for weed control. They also show...... to investigate the efficacy of four non-chemical weed control methods and glyphosate treatment, experiments were carried out on traffic islands in the growing seasons 2005 and 2006. Three trial sites were each divided into six treatment areas, which were either treated with glyphosate, flame, steam, hot air...

THE EFFECT OF WINTER CATCH CROPS ON WEED INFESTATION IN SWEET CORN DEPENDING ON THE WEED CONTROL METHODS

Directory of Open Access Journals (Sweden)

Robert Rosa

2015-02-01

Full Text Available An experiment was carried out in east-central Poland (52°06’ N, 22°55’ E over 2008–2011 to study the effect of winter catch crops on the weed infestation, number, and fresh matter of weeds in sweet corn (Zea mays L. var. saccharata. The following winter catch crops were grown: hairy vetch (Vicia villosa Roth., white clover (Trifolium repens L., winter rye (Secale cereale L., Italian ryegrass (Lolium multiflorum L. and winter turnip rape (Brassica rapa var. typica Posp.. The catch crops were sown in early September and incorporated in early May. The effect of the catch crops was compared to the effect of FYM (30 t·ha-1 and control without organic manuring (NOM. Three methods of weed control were used: HW – hand weeding, twice during the growing period, GCM – the herbicide Guardian Complete Mix 664 SE, immediately after sowing of corn seeds, Z+T – a mixture of the herbicides Zeagran 340 SE and Titus 25 WG applied at the 3–4-leaf stage of sweet corn growth. Rye and turnip rape catch crops had least weeds in their fresh matter. Sweet corn following winter catch crops was less infested by weeds than corn following farmyard manure and non-manured corn. Least weeds and their lowest weight were found after SC, BRT and VV. LM and BRT reduced weed species numbers compared with FYM and NOM. The greatest weed species diversity, determined at the corn flowering stage, was determined after SC and FYM. The number and weight of weeds were significantly lower when chemically controlled compared with hand weeding. The best results were observed after a post-emergent application of the mixture Z+T. The weed species diversity on Z+T-treated plots was clearly lower compared with GCM and HW.

Covalent Modification of Human Serum Albumin by the Natural Sesquiterpene Lactone Parthenolide

Directory of Open Access Journals (Sweden)

Michael Plöger

2015-04-01

Full Text Available The reactivity of parthenolide (PRT, a natural sesquiterpene lactone from Tanacetum parthenium (Asteraceae, with human serum albumin (HSA was studied by UHPLC/+ESI-QqTOF MS analysis after tryptic digestion of albumin samples after incubation with this compound. It was found that the single free cysteine residue, C34, of HSA (0.6 mM reacted readily with PRT when incubated at approximately 13-fold excess of PRT (8 mM. Time-course studies with PRT and its 11β,13-dihydro derivative at equimolar ratios of the reactants revealed that PRT under the chosen conditions reacts preferably with C34 and does so exclusively via its α-methylene-γ-lactone moiety, while the epoxide structure is not involved in the reaction.

Euphorbia latex: a possible source of hydrocarbons and rubber

Energy Technology Data Exchange (ETDEWEB)

Viaud, P; Teisseire, D

1975-01-01

Illustrated descriptions are given of 36 plants of potential economic value in underdeveloped tropical countries, classified by use. The plants are either wild or cultivated on a fairly local scale. Accounts of limitations and special requirements and lists of references, research contacts and sources of germ plasm are included for each species. The following tree and shrub species are included: Cnidoscolus aconitifolius, C. chayamansa and hearts of several edible palm species including Euterpe edulis (vegetables); Durio species, Garcinia mangostana, Solanum quitoense, Bactris gaspiaes, Citrus grandis, Annona muricata and Pourouma cecropiaefolia (fruits); Orbignya martiana, Caryocar species, Jessenia polycarpa and Simmondsia chinensis (oil seeds); Acacia albida, Brosimum alicastrum, Cassia sturtii, Atriplex species and Prosopis tamarungo (forage (browse)); Mauritia flexuosa (fruit, wood, etc.); Euphorbia antisyphilitica (wax); and Parthenium argentatum (rubber).

WEED CONTROL EFFECTS ON SOIL CHEMICAL CHARACTERISTICS

Directory of Open Access Journals (Sweden)

Paulo Sérgio Lima e Silva

2008-01-01

Full Text Available The weed control procedures are known to affect the soil physical attributes and the nutrient amount taken up by weed roots. This work hypothesis is that weed control methods might also affect soil chemical attributes. Four experiments were carried out, three with maize (E-1, E-2 and E-3 and one with cotton (E-4, in randomized complete blocks design arranged in split-plots, with five replications. In E-1 experiment, the plots consisted of two weed control treatments: no-weed control and weed shovel-digging at 20 and 40 days after sowing; and the subplots consisted of six maize cultivars. In the three other experiments, the plots consisted of plant cultivars: four maize cultivars (E-2 and E-3 and four cotton cultivars (E-4. And, the subplots consisted of three weed control treatments: (1 no-weed control; (2 weed shovel-digging at 20 and 40 days after sowing; and (3 intercropping with cowpea (E-2 or Gliricidia sepium (Jacq. Walp. (E-3 and E-4. In all experiments, after harvest, eight soil samples were collected from each subplot (0-20 cm depth and composed in one sample. Soil chemical analysis results indicated that the weed control by shovel-digging or intercropping may increase or decrease some soil element concentrations and the alterations depend on the element and experiment considered. In E-2, the weed shovel-dug plots showed intermediate soil pH, lower S (sum of bases values and higher soil P concentrations than the other plots. In E-4, soil K and Na concentrations in plots without weed control did not differ from plots with intercropping, and in both, K and Na values were higher than in weed shovel-dug plots. Maize and cotton cultivars did not affect soil chemical characteristics.

Applicator Training Manual for: Aquatic Weed Control.

Science.gov (United States)

Herron, James W.

The aquatic weeds discussed in this manual include algae, floating weeds, emersed weeds, and submerged weeds. Specific requirements for pesticide application are given for static water, limited flow, and moving water situations. Secondary effects of improper application rates and faulty application are described. Finally, techniques of limited…

Effect of stale seedbed preparations and subsequent weed control in lettuce (cv. Iceboll) on weed densities

NARCIS (Netherlands)

Riemens, M.M.; Weide, van der R.Y.; Bleeker, P.O.; Lotz, L.A.P.

2007-01-01

The effects of stale seedbed preparations and several weed control methods on the emergence of weeds in lettuce were studied. The specific goal was to evaluate the use of a stale seedbed in combination with chemical or mechanical weed control methods in the field. Depending on location and year,

Weed-cover versus weed-removal management in olive orchards: influence on the carbon balance at the ecosystem scale

Science.gov (United States)

Chamizo, Sonia; Serrano-Ortiz, Penélope; Vicente-Vicente, José Luis; Sánchez-Cañete, Enrique P.; López-Ballesteros, Ana; Kowalski, Andrew S.

2016-04-01

Agriculture plays an important role in the C budget at the global scale. Traditional practices based on soil tillage and applying herbicides to remove weeds have caused damage to soils and led to important losses of soil organic C and increased CO2 emissions to the atmosphere. Changing trends from traditional agriculture to conservation agriculture practices may have an important role in both C and water budgets and the transformation of agriculture from C source to C sink. The objective of this study was to analyse the effect of two treatments, weed removal by herbicides versus weed cover conservation, on the C balance in an irrigated olive orchard in SE Spain. Measurements of CO2 exchange were made from October 2014 to September 2015 using two eddy covariance towers, one for each olive crop treatment. Results show that CO2 fluxes at the ecosystem scale were similar in the two treatments during initial conditions, prior to weed growth in the soils without herbicide application (October). During the first week, daily net ecosystem exchange (NEE) was close to zero in both treatments, with values ranging from 1.06 to -0.41 g C m-2 in the weed cover treatment, and from 0.76 to -0.69 g C m-2 in the weed removal treatment. As weed growth increased, higher net CO2 assimilation was found in the treatment with weed cover. In both treatments, maximum net CO2 assimilation was found in March, with a monthly NEE of -72 and -28 g C m-2 in the treatment with and without weed cover, respectively. In May, after the weeds were cut and left on the soil, a strong increase was observed in NEE in the treatment with weed cover due to decreased CO2 assimilation and increased respiration compared to the treatment without weed cover. Therefore, soil chamber measurements showed average respiration rates of 2.57 and 1.57 μmol m-2 s-2 in the weed cover and weed removal treatment, respectively. Finally, the highest monthly NEE was registered during July, with both treatments showing a similar

The future for weed control and technology.

Science.gov (United States)

Shaner, Dale L; Beckie, Hugh J

2014-09-01

This review is both a retrospective (what have we missed?) and prospective (where are we going?) examination of weed control and technology, particularly as it applies to herbicide-resistant weed management (RWM). Major obstacles to RWM are discussed, including lack of diversity in weed management, unwillingness of many weed researchers to conduct real integrated weed management research or growers to accept recommendations, influence or role of agrichemical marketing and governmental policy and lack of multidisciplinary research. We then look ahead to new technologies that are needed for future weed control in general and RWM in particular, in areas such as non-chemical and chemical weed management, novel herbicides, site-specific weed management, drones for monitoring large areas, wider application of 'omics' and simulation model development. Finally, we discuss implementation strategies for integrated weed management to achieve RWM, development of RWM for developing countries, a new classification of herbicides based on mode of metabolism to facilitate greater stewardship and greater global exchange of information to focus efforts on areas that maximize progress in weed control and RWM. There is little doubt that new or emerging technologies will provide novel tools for RMW in the future, but will they arrive in time? © 2013 Her Majesty the Queen in Right of Canada Pest Management Science © 2013 Society of Chemical Industry.

The effect of soil tillage system and weeding time on the growth of weed and yield of soybean (Glycine max (L. Merril

Directory of Open Access Journals (Sweden)

Husni Thamrin Sebayang

2018-04-01

Full Text Available The growth and yield of soybeans can decrease due to competition from weeds. Various efforts have been made to control the growth of weeds such as land preparation and weeding periods. An experiment to study the effect of soil tillage systems and weeding time on the growth of weeds and soybean crop yield (Glycine max (L. Merril has been done in Wringinsongo Village, Tumpang Sub-District, Malang Regency from February to May 2017. The split-plot design with three replicates was used with the soil tillage system as the main plot consisting of three levels, T0: no tillage, T1: minimum tillage, and T2: conventional tillage, and weeding time as the sub plot consisting of 4 levels, P0: no weeding, P1: weeding 1 time, P2: weeding two times and P3: weeding three times. The results showed that the dominant weed species before treatment were Amaranthus spinosus (Spiny amaranth, Cynodon dactylon (Bermuda grass, Cyperus rotundus (Purple nutsedge, Ageratum conyzoides (Billygoat weed, and Portulaca oleracea (Common purslane. After treatment, the dominant weed species were Cyperus rotundus (Purple nutsedge, Amaranthus spinosus (Spiny amaranth, Ageratum conyzoides (Billygoat weed, Physalis peruviana (Cape gooseberry, and Eclipta alba (False daisy. There was no significant difference of the dry weight of weeds in conventional tillage followed by weeding 3 times at 15, 30 and 45 days after planting, and minimum tillage and no tillage. For the yield of soybeans, conventional tillage followed by weeding 3 times at 15, 30 and 45 days after planting were not significant with that of minimum tillage. The yield of soybeans was lower than that of with no tillage and no weeding.

Prospects for site specific weed management

DEFF Research Database (Denmark)

Christensen, Svend; Rasmussen, Jesper; Pedersen, Søren Marcus

2014-01-01

Research on Site Specific Weed Management (SSWM) started in the late 80's. Since that moment, considerable research has been conducted on different aspects of SSWM, from fundamental studies on the spatial ecology of weeds to the applied development and testing of new technologies for weed detection...

Herbicide-resistant weed management: focus on glyphosate.

Science.gov (United States)

Beckie, Hugh J

2011-09-01

This review focuses on proactive and reactive management of glyphosate-resistant (GR) weeds. Glyphosate resistance in weeds has evolved under recurrent glyphosate usage, with little or no diversity in weed management practices. The main herbicide strategy for proactively or reactively managing GR weeds is to supplement glyphosate with herbicides of alternative modes of action and with soil-residual activity. These herbicides can be applied in sequences or mixtures. Proactive or reactive GR weed management can be aided by crop cultivars with alternative single or stacked herbicide-resistance traits, which will become increasingly available to growers in the future. Many growers with GR weeds continue to use glyphosate because of its economical broad-spectrum weed control. Government farm policies, pesticide regulatory policies and industry actions should encourage growers to adopt a more proactive approach to GR weed management by providing the best information and training on management practices, information on the benefits of proactive management and voluntary incentives, as appropriate. Results from recent surveys in the United States indicate that such a change in grower attitudes may be occurring because of enhanced awareness of the benefits of proactive management and the relative cost of the reactive management of GR weeds. Copyright © 2011 Society of Chemical Industry.

Weed infestation of spring common wheat (Triticum aestivum L. grown in monoculture depending on the cover crop and weed control method

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Dorota Gawęda

2012-10-01

Full Text Available The aim of this 3-year field study was to evaluate the effect of some stubble crops and in-crop weed control methods on the species composition, number and air-dry weight of weeds in a wheat crop grown in short-term monoculture. The study was conducted in the period 2009-2011 in the Uhrusk Experimental Farm on mixed rendzina soil classified as very good rye soil complex. It included various types of stubble crops ploughed in each year (control treatment without cover crop, white mustard, lacy phacelia, a mixture of legumes – narrow-leaf lupin + field pea and methods of weed control in spring wheat (mechanical, mechanical and chemical, chemical weed control. On average during the study period, all stubble crops used reduced the air-dry weight of weds in the treatments with mechanical weed management relative to the control treatment. Irrespective of the weed control method, the number of weeds in the wheat crop was significantly lower only after the ploughing in of white mustard. Mechanical weed management proved to be less effective in reducing the number and dry weight of weeds compared to other weed control methods. The white mustard and legume mixture cover crops had a reducing effect on the number of weed species in relation to the treatment without cover crops. The highest floristic diversity of weed communities was found in the spring wheat crop in which only mechanical weeding alone was used.

Bioherbicides: Current knowledge on weed control mechanism.

Science.gov (United States)

Radhakrishnan, Ramalingam; Alqarawi, Abdulaziz A; Abd Allah, Elsayed Fathi

2018-04-17

Weed control is a challenging event during crop cultivation. Integrated management, including the application of bioherbicides, is an emerging method for weed control in sustainable agriculture. Plant extracts, allelochemicals and some microbes are utilized as bioherbicides to control weed populations. Bioherbicides based on plants and microbes inhibit the germination and growth of weeds; however,few studies conducted in weed physiology. This review ascribes the current knowledge of the physiological changes in weeds that occur during the exposure to bioherbicides. Plant extracts or metabolites are absorbed by weed seeds, which initiates damage to the cell membrane, DNA, mitosis, amylase activity and other biochemical processes and delays or inhibits seed germination. The growth of weeds is also retarded due to low rates of root-cell division, nutrient uptake, photosynthetic pigment synthesis, and plant growth hormone synthesis, while the productions of reactive oxygen species (ROS) and stress-mediated hormones increase, including irregular antioxidant activity. However, lytic enzymes and toxic substances secreted from microbes degrade the weed seed coat and utilize the endosperm for survival, which inhibits seed germination. The microbes grow through the intercellular spaces to reach the root core, and the deposition of toxins in the cells affects cell division and cellular functions. Some of the metabolites of deleterious microbes cause disease, necrosis and chlorosis,which inhibit the germination and growth of weed seeds by suppressing photosynthesis and gibberellin activities and enhancing ROS, abscisic acid and ethylene. This review explains the effects of bioherbicides (derived from plants and microbes) on weed-plant physiology to elucidate their modes of action. Copyright © 2018 Elsevier Inc. All rights reserved.

An ultrasonic system for weed detection in cereal crops.

Science.gov (United States)

Andújar, Dionisio; Weis, Martin; Gerhards, Roland

2012-12-13

Site-specific weed management requires sensing of the actual weed infestation levels in agricultural fields to adapt the management accordingly. However, sophisticated sensor systems are not yet in wider practical use, since they are not easily available for the farmers and their handling as well as the management practice requires additional efforts. A new sensor-based weed detection method is presented in this paper and its applicability to cereal crops is evaluated. An ultrasonic distance sensor for the determination of plant heights was used for weed detection. It was hypothesised that the weed infested zones have a higher amount of biomass than non-infested areas and that this can be determined by plant height measurements. Ultrasonic distance measurements were taken in a winter wheat field infested by grass weeds and broad-leaved weeds. A total of 80 and 40 circular-shaped samples of different weed densities and compositions were assessed at two different dates. The sensor was pointed directly to the ground for height determination. In the following, weeds were counted and then removed from the sample locations. Grass weeds and broad-leaved weeds were separately removed. Differences between weed infested and weed-free measurements were determined. Dry-matter of weeds and crop was assessed and evaluated together with the sensor measurements. RGB images were taken prior and after weed removal to determine the coverage percentages of weeds and crop per sampling point. Image processing steps included EGI (excess green index) computation and thresholding to separate plants and background. The relationship between ultrasonic readings and the corresponding coverage of the crop and weeds were assessed using multiple regression analysis. Results revealed a height difference between infested and non-infested sample locations. Density and biomass of weeds present in the sample influenced the ultrasonic readings. The possibilities of weed group discrimination were

Developments in physical weed control in Northwest Europe

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Riemens, Marieen

2016-02-01

Full Text Available In North West Europe there is an increasing need for advanced weed control methods. This paper gives an overview of the developments in physical weed control methods. Current innovations in interrow weeding focus on systems that take over the steering function of the driver in order to make them more precise and reduce crop losses. The latest developments in intrarow weeding techniques involve technologies that automatically detect and classify crop and weed plants and use this information to guide a weeding device. Several commercially available examples are presented.

Grass and weed killer poisoning

Science.gov (United States)

... medlineplus.gov/ency/article/002838.htm Grass and weed killer poisoning To use the sharing features on this page, please enable JavaScript. Many weed killers contain dangerous chemicals that are harmful if ...

Weed supression by smother crops and selective herbicides

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Severino Francisco José

2004-01-01

Full Text Available Using a smother crop is thought to suppress weed density and to add other beneficial effects in sustainable agricultural systems. Weed suppression ought to be considered an essential component of integrated weed management. However, very little is known about the effects of green manure plants on weeds. This study evaluated the influence of three green manure species on weed suppression and selectivity of herbicides. A field experiment was designed to determine the effect of the green manure species Crotalaria juncea, Arachis pintoi and pigeon pea on the weeds Brachiaria decumbens, guineagrass and hairy beggarticks, and on the natural weed infestation in the inter rows area of an avocado orchard. The weed species were suppressed differently by each green manure species. Soil samples collected from the field experiment presented a residual effect, of at least 30 d, in suppressing weed seed bank recruitment; this residual effect was caused by the residues of the green manure present in the soil. When the green manure was incorporated into the top 5 cm of soil or left on the surface, in a greenhouse experiment, the emergence of weed seeds was significantly inhibited, depending on the species, and on the amount and depth of green manure incorporation. Greenhouse experiments indicate that pre-emergence herbicides cause lower phytotoxicity than post-emergence Arachis pintoi. Smother crops using green manure species, when well established in an area, provide additional weed control to the cropping system and are effective and valuable tools in integrated weed management.

A non-chemical system for online weed control.

Science.gov (United States)

Rueda-Ayala, Victor; Peteinatos, Gerassimos; Gerhards, Roland; Andújar, Dionisio

2015-03-30

Non-chemical weed control methods need to be directed towards a site-specific weeding approach, in order to be able to compete the conventional herbicide equivalents. A system for online weed control was developed. It automatically adjusts the tine angle of a harrow and creates different levels of intensity: from gentle to aggressive. Two experimental plots in a maize field were harrowed with two consecutive passes. The plots presented from low to high weed infestation levels. Discriminant capabilities of an ultrasonic sensor were used to determine the crop and weed variability of the field. A controlling unit used ultrasonic readings to adjust the tine angle, producing an appropriate harrowing intensity. Thus, areas with high crop and weed densities were more aggressively harrowed, while areas with lower densities were cultivated with a gentler treatment; areas with very low densities or without weeds were not treated. Although the weed development was relatively advanced and the soil surface was hard, the weed control achieved by the system reached an average of 51% (20%-91%), without causing significant crop damage as a result of harrowing. This system is proposed as a relatively low cost, online, and real-time automatic harrow that improves the weed control efficacy, reduces energy consumption, and avoids the usage of herbicide.

Prediction of the competitive effects of weeds on crop yields based on the relative leaf area of weeds

DEFF Research Database (Denmark)

Lotz, L. A. P.; Christensen, Svend; Cloutier, D.

1996-01-01

. alba whereas the density model did not. A parameter that allows the maximum yield loss to be smaller than 100% was mostly not needed to describe the effects of weed competition. The parameter that denotes the competitiveness of the weed species with respect to the crop decreased the later the relative......For implementation of simple yield loss models into threshold-based weed management systems, a thorough validation is needed over a great diversity of sites. Yield losses by competition wsth Sinapis alba L. (white mustard) as a model weed, were studied in 12 experiments in sugar beet (Beta vulgaris...... L.) and in 11 experiments in spring wheat (Triticum aestivum L.). Most data sets were heller described by a model based on the relative leaf area of the weed than by a hyperbolic model based on weed density. This leaf area model accounted for (part of) the effect of different emerging times of the S...

Adapting weed management in rice to changing climates

NARCIS (Netherlands)

Rodenburg, J.; Meinke, H.B.

2011-01-01

This paper provides some of the scientific background on how projected environmental conditions could affect weeds and weed management in rice in Africa. Elevated CO2 levels may have positive effects on rice competitiveness with C4 weeds, but these are generally outnumbered by C3 species in weed

Weed Garden: An Effective Tool for Extension Education

Science.gov (United States)

Beck, Leslie; Patton, Aaron J.

2015-01-01

A weed garden was constructed to quantify and improve identification skills among clientele. The garden was planted with over 100 weed species based on surveys on problematic weeds. The weed garden proved useful for introducing additional hands-on learning activities into traditional lecture-based seminars. Through seminar and field day attendee…

WEED MANAGEMENT AND CONTROL IN POTATOES

Directory of Open Access Journals (Sweden)

Marcelo Cleón de Castro Silva

2011-07-01

Full Text Available This review shows instructions to potatoes' farmer about behavior of the weeds and how to manage them so as to minimize loss of productivity through the use of control strategies for potato crop. The prevention consists in adoption of practices that prevents entry of unwanted species of weeds in the planting site. The control reduces the infestation of these species, but this practice does not eradicate them completely. However, it needs to control the weeds before the area preparation for planting the tubers until complete closure of the soil by shoots of potatoes during the critical period. After covering the soil, the potato crop does not suffer negative interference caused by weeds. The cultural practices include a good plane for harvest, plant crop rotation, the planting of appropriate plants for covering the soil, the ideal space to the planting and the correct time to potato planting. The control must be efficient to reduce the number of weeds in the area to avoid economic losses to farmers. It is necessary to establish weed management strategies in order to maintain sustainable farming systems, preserving the environment and quality of life of the farmer.

INFLUENCE OF CROPPING SYSTEM AND WEED MANAGEMENT PRACTICE ON EMERGENCE, GROWTH OF WEEDS, YIELD OF MAIZE (Zea mays L. AND COWPEA (Vigna unguiculata L.

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Felix Ogar Takim

2014-06-01

Full Text Available The effects of cropping system and weed management practice on weed seedling emergence, weed biomass production and yield of maize and cowpea were examined at Ilorin, in the southern Guinea savanna (9°29' N, 4°35' E and 307 m ASL of Nigeria. Weed emergence occurred throughout the 3-15 weeks after planting (WAP. Forty-three weed species belonging to 38 genera within 20 families were encountered. Fimbristylis littoralis Gaudet, Tridax procumbens L and Eleusine indica Gaertn were the most prevalent weed species. Cropping system and weed management practice significantly affected weed emergence. Significantly (p≤0.05 lower number of weeds emerged in the intercropped and herbicide treated plots while higher weed densities and weed biomass were recorded in the uncropped and unweeded control plots than in the other plots. While aggregate crop yields were significantly higher in the intercropped than in the sole plots, component crop yields were higher under the sole cropping than in the intercrop. The implication of the results on weed management is discussed.

Chemical weed control in Spinach (Spiniacia oleracea

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A. Modhej

2016-03-01

Full Text Available Introduction Spinach (Spinacia oleracea is an annual plant of family Chenopodiaceae. It is cultivated in temperate and cold regions in Khouzestan in autumn and winter. Weeds are the main problems that limit the production of vegetables. Competition ability of spinach against weeds is very low and weeds cause the loss of quality and quantity in this plant. Weeds reduce germination and establishment and growth of spinach. Weed management in spinach should be done at the beginning of the season. Hand weeding is the best way to control weeds spinach, although due to the high cost it is not cost effective, but is steel common in large areas. Weed control spinach, using chemical methods, the number of weeds are kept below the threshold of economic damage. Materials and Methods The experiment was conducted in a randomized complete block design with 15 treatments and three replications. Treatments included pre-plant application of EPTC at 5 and 6 lit ha-1, pre-plant application of Trifluralin at 2 lit ha-1, pre-plant and pre-emergence application of Pendimethalin at 3 lit ha-1, pre-emergence and post-emergence application of Meteribouzin at 300 g ha-1, pre-emergence and post-emergence application of Meteribouzin at 400 g ha-1, pre-emergence and post-emergence application of Imazethapyr at 0.7 lit ha-1, pre-emergence and post-emergence application of Imazethapyr at 1 lit ha-1, weedy and weed free checks. Each plot the size of 2.5 × 2 meters and 10 row cultivation with distances between rows of 15 cm and the distance between the plants 25 cm and the sowing depth was 3 cm. The herbicide treatments were applied to the back sprayer with Flat fan nozzle with volume of consumption of 240 lit ha-1 solution. The final harvest was about 50 days after emergence. Sampling of weeds 10 days before harvest was performed with using quadrate 0.5 ×0.5. Results Discussion Important broad-leaf and narrow leaf weeds observed in the field, included field bindweed

Weed management strategies for castor bean crops

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Augusto Guerreiro Fontoura Costa

2014-04-01

Full Text Available Castor bean crops are agriculturally relevant due to the quality and versatility of their oil, both for the chemical industry and for biodiesel production. Proper weed management is important for both the cultivation and the yield of castor bean crops; therefore, the intention of the present work is to review pertinent information regarding weed management, including the studies regarding weed interference periods, chemical controls for use in different crop production systems and herbicide selectivity, for castor bean crops. Weed science research for castor bean crops is scarce. One of the main weed management challenges for castor bean crops is the absence of herbicides registered with the Ministry of Agriculture, Livestock and Food Supply (MALFS. Research for viable herbicides for weed control in castor bean crops should be directed by research and/or rural extension institutions, associations and farmers cooperatives, as well as by manufactures, for the registration of these selective herbicides, which would be primarily used to control eudicotyledons in castor bean crops. New studies involving the integration of weed control methods in castor bean also may increase the efficiency of weed management, for both small farmers using traditional crop methods in the Brazilian Northeast region, as well as for areas with the potential for large scale production, using conservation tillage systems, such as the no-tillage crop production system.

Combustion synthesis of MgO nanoparticles using plant extract: Structural characterization and photoluminescence studies

Science.gov (United States)

Kumar, Danith; Yadav, L. S. Reddy; Lingaraju, K.; Manjunath, K.; Suresh, D.; Prasad, Daruka; Nagabhushana, H.; Sharma, S. C.; Naika, H. Raja; Chikkahanumantharayappa, Nagaraju, G.

2015-06-01

Magnesium oxide nanoparticles (MgO Nps) have been successfully synthesized via solution combustion method using Parthenium plant extract as fuel for the first time. Powder X-ray diffraction (PXRD) pattern reveal that product belongs to the cubic phase (Periclase). FTIR spectrum shows the band at 822 cm-1 indicates the formation of cubic periclase MgO. The optical band gap of MgO Nps estimated from UV -Vis spectrum was found to be in the range 5.40-5.45 eV. SEM images showed that, the product is agglomerated and particle in nature. Photoluminescence (PL) studies shows violet emission at 390 nm, blue emission at 470 nm and green emission at 550 nm. MgO Nps shows good photocatalytic activity for the degradation of methylene blue (MB) dye under UV/Sun light irradiation.

Weed Biomass and Weed Species Diversity of Juvenile Citrus Trees Intercrop with some Arable Crops

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Patience Mojibade OLORUNMAIYE

2012-02-01

Full Text Available A preliminary study was carried out to evaluate the performances of eight crops in the intercrop of citrus with arable crops at the National Horticultural Research Institute (NIHORT Ibadan, Nigeria. Eight arable crops: maize, cucumber, sweet potato, Corchorus olitorius, large green, grain amaranth, Mucuna pruriens var. utilis, and groundnut were intercropped with young citrus trees in the early planting season of 2010 with sole citrus as control. The experiment was laid out in a completely randomized block design with three replicates. Data were collected on weed flora, weed density and weed dry weight. Results showed that the relative frequencies of weeds in all the plots were less than 4% at both 6 and 9WAP. Gomphrena celosoides, Oldenlandia corymbosa and Tridax procumbens were most preponderant in appearing in all the plots. Tridax procumbens had a consistent relative frequency (2.34% in all the plots except in citrus/maize plot (0.78% at 9 WAP. Significantly lower broadleaf weed densities were obtained in citrus/sweet potato, citrus/large green, control plot and citrus/cucumber (28.67, 45.00, 50.00 and 76.33 m-2 respectively than in citrus/groundnut plot (143.00 m-2. Similarly, significantly lower grass weed densities were produced in citrus/Mucuna and citrus/sweet potato (0.33 m-2 each plots than the control plot (11.33 m-2. Whereas citrus/corchorus plot produced significantly lower broadleaf weed dry weight (37.59 g m-2 than citrus/Mucuna plot (126.47 g m-2 at 3WAP, citrus/large green plot (16.15 g m-2 and citrus/groundnut plot (123.25 g m-2 followed the same trend at 6 WAP. Sedges dry weights were less than 7 g m-2 in all the plots compared with control plot.

Critical Period of Weed Control in Aerobic Rice

Science.gov (United States)

Anwar, M. P.; Juraimi, A. S.; Samedani, B.; Puteh, A.; Man, A.

2012-01-01

Critical period of weed control is the foundation of integrated weed management and, hence, can be considered the first step to design weed control strategy. To determine critical period of weed control of aerobic rice, field trials were conducted during 2010/2011 at Universiti Putra Malaysia. A quantitative series of treatments comprising two components, (a) increasing duration of weed interference and (b) increasing length of weed-free period, were imposed. Critical period was determined through Logistic and Gompertz equations. Critical period varied between seasons; in main season, it started earlier and lasted longer, as compared to off-season. The onset of the critical period was found relatively stable between seasons, while the end was more variable. Critical period was determined as 7–49 days after seeding in off-season and 7–53 days in main season to achieve 95% of weed-free yield, and 23–40 days in off-season and 21–43 days in main season to achieve 90% of weed-free yield. Since 5% yield loss level is not practical from economic view point, a 10% yield loss may be considered excellent from economic view point. Therefore, aerobic rice should be kept weed-free during 21–43 days for better yield and higher economic return. PMID:22778701

Weed Recognition Framework for Robotic Precision Farming

DEFF Research Database (Denmark)

Kounalakis, Tsampikos; Triantafyllidis, Georgios; Nalpantidis, Lazaros

2016-01-01

using advanced encoding and machine learning algorithms. The resulting system can be applied in a variety of environments, plantation or weed types. This results in a novel and generic weed control approach, that in our knowledge is unique among weed recognition methods and systems. For the experimental...

Weeds optimally grow in peat swamp after burning

Directory of Open Access Journals (Sweden)

P.D. Susanti

2014-07-01

Full Text Available After clearing land by burning the peat, then the weeds and undergrowth will flourish. Even sometimes, the weeds are eventually burned again. Weed is known as a destroyer plant that has to be controlled. Through proper treatment, the existing weeds in peatlands can be potentiallly exploited. The purpose of this study was to determine the calorific value of briquettes as one of peatland weeds utilization. The results showed that the calorific value ranged from 2,492 cal/g to 5,230 cal/g. The lowest calorific value was on ‘teki kecil’ grass (Scirpus grossus Lf, while the highest calorific value was observed for ‘bantalaki grass’ (Hymenachne amplexicaulis Nees. The high calorific value of the peat weeds are potential for biomass briquettes raw materials. The utilization and use of peat weed briquettes as a raw materials expected can reduce land degradation due to peat swamp burning

Spatial analysis of weed patterns

NARCIS (Netherlands)

Heijting, S.

2007-01-01

Keywords: Spatial analysis, weed patterns, Mead’s test, space-time correlograms, 2-D correlograms, dispersal, Generalized Linear Models, heterogeneity, soil, Taylor’s power law. Weeds in agriculture occur in patches. This thesis is a contribution to the characterization of this patchiness, to its

Weed detection using unmanned aircraft vehicles

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Pflanz, Michael

2014-03-01

Full Text Available In contrast to agricultural remote sensing technologies, which are based on images from satellites or manned aircrafts, photogrammetry at low altitude from unmanned aircraft vehicles lead to higher spatial resolution, real-time processing and lower costs. Moreover multicopter aircrafts are suitable vehicles to perform precise path or stationary flights. In terms of vegetation photogrammetry this minimises motion blur and provide better image overlapping for stitching and mapping procedures. Through improved image analyses and through the recent increase in the availability of powerful batteries, microcontrollers and multispectral cameras, it can be expected in future that spatial mapping of weeds from low altitudes will be promoted. A small unmanned aircraft vehicle with a modified RGB camera was tested taking images from agricultural fields. A microcopter with six rotors was applied. The hexacopter in particular is GPS controlled and operates within predefined areas at given altitudes (from 5 to 10 m. Different scenarios of photogrammetrically weed detection have been carried out regarding to variable altitude, image resolution, weed and crop growth stages. First experiences with microcopter showed a high potential for site-specific weed control. Images analyses with regards to recognition of weed patches can be used to adapt herbicide applications to varying weed occurrence across a field.

Effect of Different Methods of Chemical Weed Control Irrigation Regimes on Weed Biomass and Safflower Yield

Directory of Open Access Journals (Sweden)

M. Matinfar

2011-06-01

Full Text Available In order to investigate the effects of different weed control methods and moisture regimes on safflower (Carthamus tinctorius, a field split plot experiment based on randomized complete block design with 4 replications was conducted in Takestan Iran, during growing seasons of 2007-8. Three irrigations regimes (normal irrigation, restricted irrigation at stem elongation and restricted irrigation at  flowering stage were assigned to the main plots and nine chemical weed control method (complete hand weeding, treflan with 2 L/ha as pre plant herbicide, sonalan with 3 L/ha ad pre plant herbicide, estomp with 3 L/ha as pre plant herbicide, gallant super with 0/75 L/ha as post emergence herbicide, treflan with 2 L/ha as pre plant herbicide+ gallant super with 0/75 L/ha as post emergence herbicide, sonalan with 3 L/ha as pre plant herbicide + gallant super with 0/75 L/ha as post emergence herbicide estomp with 3 L/ha as pre plant herbicide + gallant super with 0/75 L/ha as post emergence herbicide and without hand weeding to sub- plots. At the end of growing period traits like number of head   per plant, number of seed per head, 1000 grain weight, percent of seed oil, yield of seed oil and grain yield were measured. Results indicated that treflan + gallant super treatment in restricted irrigation at stem elongation stage had the lowest dry weight of weeds. In this study maximum grain yield (2927 Kg/ha was achieved from hand weeding + usual irrigation treatments. In general treflan + gallant super treatment was the most effective treatment on safflower yield and weed control.

Weed infestation of onion in soil reduced cultivation system

Directory of Open Access Journals (Sweden)

Marzena Błażej-Woźniak

2013-12-01

Full Text Available Field experiment was conducted in the years 1998-2000 in GD Felin. The influence of no-tillage cultivation and conventional tillage with spring ploughing on weed infestation of onion was compared. In experiment four cover crop mulches (Sinapis alba L., Vicia sativa L., Phacelia tanacetifolia B., Avena sativa L. were applied. From annual weeds in weed infestation of onion in great number Matricaria chamomilla L., and Senecio vulgaris L. stepped out. and from perennial - Agropyron repens (L.P.B. Reduced soil cultivation system (no-tillage caused the significant growth of primary weed infestation of onion in comparison with conventional tillage. In all years of investigations the executed pre-sowing ploughing limited significantly the annual weeds' number in primary weed infestation. The applied mulches from cover plants limited in considerable degree the number of primary weed infestation. In all years of investigations the most weeds stepped out on control object. Among investigated cover crop mulches Vicia sativa L. and Avena sativa L. had a profitable effect on decrease of onion`s primary weed infestation. Soil cultivation system and cover crop mulches had no signi ficant residual influence on the secondary weed infestation of onion.

Virus infection of a weed increases vector attraction to and vector fitness on the weed.

Science.gov (United States)

Chen, Gong; Pan, Huipeng; Xie, Wen; Wang, Shaoli; Wu, Qingjun; Fang, Yong; Shi, Xiaobin; Zhang, Youjun

2013-01-01

Weeds are important in the ecology of field crops, and when crops are harvested, weeds often become the main hosts for plant viruses and their insect vectors. Few studies, however, have examined the relationships between plant viruses, vectors, and weeds. Here, we investigated how infection of the weed Datura stramonium L. by tomato yellow leaf curl virus (TYLCV) affects the host preference and performance of the TYLCV vector, Bemisia tabaci (Gennadius) Q. The results of a choice experiment indicated that B. tabaci Q preferentially settled and oviposited on TYLCV-infected plants rather than on healthy plants. In addition, B. tabaci Q performed better on TYLCV-infected plants than on healthy plants. These results demonstrate that TYLCV is indirectly mutualistic to B. tabaci Q. The mutually beneficial interaction between TYLCV and B. tabaci Q may help explain the concurrent outbreaks of TYLCV and B. tabaci Q in China.

Integrated weed management in wheat

International Nuclear Information System (INIS)

Marwat, K.B.; Khan, M.A.; Nawab, K.; Khattak, A.M.

2011-01-01

The paper summarizes the results of an experiment conducted on wheat at Kohat, Khyber Pakhtunkhwa, Pakistan during winter 2004-05. Randomized complete block design with split-split-plot arrangement was used where wheat line and broadcast sowing were kept in main plots. Seed rates (100 and 150 kg ha-1) were assigned as sub-plots, while four herbicides (Topik, Isoproturon, Puma super and Buctril super) and weed check were assigned to sub-sub-plots. Results revealed that higher biological yield was recorded in line sowing. However, higher wheat seed rate decreased weed biomass and increased biological yield. Herbicides proved to be effective in decreasing weed biomass and enhancing grain yield and its contributing traits. It was suggested that line sowing in combination with higher seeding rate and Buctril super should be used in an integrated weed management fashion. However further studies are required to investigate various ranges of seeding rate and herbicides doses. (author)

Latex content and biomass increase in Mycorrhizal guayule (Parthenium argentatum) under field conditions

Energy Technology Data Exchange (ETDEWEB)

Bloss, H.E.; Pfeiffer, C.M.

1984-01-01

Guayule seedlings were inoculated with two Glomus species in pasteurised soil and grown in the glasshouse without added fertilizer for 8 weeks prior to transplanting to the field. The survival rate of transplanted guayule seedlings was increased by inoculation with vesicular arbuscular mycorrhizal fungi compared wtih uninoculated controls. Inoculated guayule had greater concentrations of Ca, Fe, Mg and Mn at six months of age, and greater concentrations of Ca, Mg, and Zn at 12 months of age than did uninoculated plants. The latex content of both roots and shoots of guayule was greater in inoculated than in uninoculated guayule plants at 12 and 18 months of age. The resin content remained unchanged between treatments irrespective of sampling date.

Weed Identification Distribution and Mapping at Njoro and Katumani

International Nuclear Information System (INIS)

Mwangi, H; Alembi, D.K

1999-01-01

The study was a response to the need from Katumani DFRC and Njoro (NPBC) Crop protection team request for support service in identification of weed spp. in their mandated areas. From their ongoing adaptive research they encountered ceratin weed spp. which were troublesome and they could not identify and their contact farmers had expressed concern over the weed constraint. A survey in the mentioned areas were carried out in the long/short rains 1997. In the fields, the sites were selected after every 10 km. The field selected was traversed and a quadrat measuring 1m 2 was placed randomly and weeds identified. General Position System (GPS) recorded the position. Two methods of identifying weeds thus on the spot in the field in situ and unidentified weed samples were carefully collected, labelled and preserved for identification in the laboratory of NARL herbarium. Weed distribution was determined using scale 1-4 where 1=1 plant/M 2 , 2=2-5 plants/m 2 , 3=6-20 plants/m 2 ,4=>20 plants m /2. The results show identified weeds in different categories; dominant, troublesome, indigenous and weed introduced within the ten years as percieved by farmers. Developed weed maps are presented for specific districts

Dry Bean Morpho-Physiological Responses to Gradual Weed Biomass Accumulation

Directory of Open Access Journals (Sweden)

Hossein GHAMARI

2013-02-01

Full Text Available Field study was carried out in 2011 in west of Iran to assess responses of dry bean (Phaseolus vulgaris L. morpho-physiological traits to gradual weed biomass accumulation. The treatments consisted of two different periods of weed interference, which weeds either infested the plots or removed for an increasing duration of time (0, 10, 20, 30, 40, 50 days after crop emergence. Relative dominance and relative importance of weed species fluctuated over the crop cycle. As the duration of weed interference was increased, a declining trend of crop growth rate (CGR was observed. When weeds were allowed to compete with crop throughout the crop cycle, maximum value of CGR was decreased from 25.57 g m-2 days in full season weed free treatment to 16.78 g m-2 days in full season weed infested treatment. Effect of treatments on leaf area index (LAI was significant. Weed removal increased LAI but it could not significantly affect this trait, at the early of growing season. Weed interference caused a significant reduction on number of branches. The minimum number of branches was registered in full season weed infested treatment (2.58 branches per plant, while the maximum one was observed in the full season weed free treatment (4.25 branches per plant. Weed competition severely reduced crop yield. At 10 and 20 days after crop emergence, weed infestation could not significantly affect the yield. A negative relationship between weeds’ dry matter accumulation and LAI as well as number of branches was observed which signify the vulnerability of these morpho-physiological traits to weed competition.

Soil solarization for weed control in carrot

Directory of Open Access Journals (Sweden)

MARENCO RICARDO ANTONIO

2000-01-01

Full Text Available Soil solarization is a technique used for weed and plant disease control in regions with high levels of solar radiation. The effect of solarization (0, 3, 6, and 9 weeks upon weed populations, carrot (Daucus carota L. cv. Brasília yield and nematode infestation in carrot roots was studied in São Luís (2º35' S; 44º10' W, MA, Brazil, using transparent polyethylene films (100 and 150 mm of thickness. The maximum temperature at 5 cm of depth was about 10ºC warmer in solarized soil than in control plots. In the study 20 weed types were recorded. Solarization reduced weed biomass and density in about 50% of weed species, including Cyperus spp., Chamaecrista nictans var. paraguariensis (Chod & Hassl. Irwin & Barneby, Marsypianthes chamaedrys (Vahl O. Kuntze, Mitracarpus sp., Mollugo verticillata L., Sebastiania corniculata M. Arg., and Spigelia anthelmia L. Approximately 40% of species in the weed flora were not affected by soil mulching. Furthermore, seed germination of Commelina benghalensis L. was increased by soil solarization. Marketable yield of carrots was greater in solarized soil than in the unsolarized one. It was concluded that solarization for nine weeks increases carrot yield and is effective for controlling more than half of the weed species recorded. Mulching was not effective for controlling root-knot nematodes in carrot.

Descriptive and mechanistic models of crop–weed competition

NARCIS (Netherlands)

Bastiaans, L.; Storkey, J.

2017-01-01

Crop-weed competitive relations are an important element of agroecosystems. Quantifying and understanding them helps to design appropriate weed management at operational, tactical and strategic level. This chapter presents and discusses simple descriptive and more mechanistic models for crop-weed

7 CFR 201.50 - Weed seed.

Science.gov (United States)

2010-01-01

... REGULATIONS Purity Analysis in the Administration of the Act § 201.50 Weed seed. Seeds (including bulblets or... sieve are considered weed seeds. For wild onion and wild garlic (Allium spp.) bulblets classed as inert...

Weed Control in Clean Agriculture: A Review1

OpenAIRE

ABOUZIENA,H.F.; HAGGAG,W.M.

2016-01-01

ABSTRACT Weed control is consider the major obstacle for the growers in the organic farming. Lower plant productivity in organic farming mainly related to the poor weed control. It is widely known, in most cases, that losses caused by weeds exceeded the losses from any category of agricultural pests. Under water-stress condition, weeds can reduce crop yields more than 50% through moisture competition alone. In the light of the environmental and toxicological problems created by herbicides, it...

Image analysis as a non-destructive method to assess regrowth of weeds after repeated flame weeding

DEFF Research Database (Denmark)

Rask, Anne Merete; Kristoffersen, Palle; Andreasen, Christian

2013-01-01

picture of the long-term effect of repeated treatments. Image analysis was most useful for assessing the effect of repeated treatments when weed cover was relatively low (below 40%) and when plots contained relatively much withered plant material. However, when weed cover is close to 100%, dry weight......, and therefore it may influence the long-term effect of repeated treatments. Visual assessment of weed cover or image analysis do not affect the remaining parts of the weed plants after treatment, but the methods may have other disadvantages. In order to evaluate and compare three methods we measured changes...... in vegetation cover of perennial ryegrass after flaming by (1) a simple image analysis programme counting green pixels, (2) visual assessment of images and (3) by taking biomass samples. Plants were flame treated with eight different dosages (0, 20, 30, 35, 45, 60, 90 and 180 kg propane ha-1) and with various...

Bioenergy potential of eight common aquatic weeds

Energy Technology Data Exchange (ETDEWEB)

Abbasi, S.A.; Nipaney, P.C.; Schaumberg, G.D. (Pondicherry (Central) Univ. (IN). Salim Ali School of Ecology)

1990-01-01

Eight common aquatic weeds Salvinia molesta, Hydrilla verticillata, Nymphaea stellata, Azolla pinnata, Ceratopteris sp. Scirpus sp. Cyperus sp, and Utricularia reticulata were digested anaerobically to produce methane. The carbon to nitrogen (C/N) ratio, carbon to phosphorus (C/P) ratio, and the volatile solids (VS) content of the weeds varied widely. No trend between these factors and the methane yield was discernable; the possible reasons are discussed. The energy potential of the weeds per unit area of the weed crop was worked out. Natural stands of salvinia, such as the one employed in the present investigation, would yield energy (methane) of the order of 10{sup 8} Kcal/ha/yr. (author).

A STUDY ON WEED CONTROL IN SOYBEAN

Directory of Open Access Journals (Sweden)

S. TJITROSEMITO

1991-01-01

Full Text Available Two field experiments on weed control in soybeans were carried out at BIOTROP, Bogor, Indonesia from February to June, 1989. The critical period for weed control was found to be between 20 - 40 days after planting of soybean (c. v. Wilis grown at a planting distance of 40 x 10 cm. It did not coincide with the fastest growth in terms of trifoliate leaf number. Further studies were suggested to understand the physiological growth of soybean related to weed control. Pendimethalin at 660- 1320 g a.e./ha applied one day after sowing did not cause any phytotoxic effect to soybean and had good weed control performance.

Conservation implications of weed management of lake reservoirs ...

African Journals Online (AJOL)

Management of weeds around lake reservoirs is often implemented to reduce any possibility of siltation. However, machineries used in weed management have resulted in habitat degradation and geometrical multiplication of weeds by chopping rhizomes and scattering seeds. In general, the removal offers some feedbacks ...

WHITE BLISTER SPECIES (Albuginaceae ON WEEDS

Directory of Open Access Journals (Sweden)

Karolina Vrandečić

2011-06-01

Full Text Available The obligate fungi inside the family Albuginaceae are widespread world wide and cause white rust or white blister disease. Mycopopulation of weeds has been researched within the project „The role of weeds in epidemiology of row-crop diseases“. The aim of this research was to identify white blister species occurring on weeds in Eastern Croatia. Weed plants with disease symptoms characteristic for white blister species have been collected since 2001 on location Slavonia and Baranja country. Determination of white blister species was based on morphological characters of pathogen and the host. Wilsoniana bliti was determined on Amaranthus retroflexus and Amaranthus hybridus leaves. Capsella bursa pastoris is a host for Albugo candida. Ambrosia artemisiifolia is a host for Pustula sp. and Cirsium arvense was found to be host for Pustula spinulosa. Wilsoniana portulaceae was determined on Portulaca oleracea.

Impact of fungicides on weed growth

Directory of Open Access Journals (Sweden)

Nordmeyer, Henning

2014-02-01

Full Text Available The study has shown that fungicides influence the growth of weeds. The competition against crops will be substantially reduced. Bioassays in a climate chamber variation in temperature as well as different lightning phases and microplot trials under semi field levels were carried out to investigate the influence of fungicides on weed growth. Selected weed species (Alopecurus myosuroides, Viola arvensis, Galium aparine, Stellaria media, Lamium purpureum have been examined with different dose rates of fungicides (Adexar, Bravo 500, Diamant, Crupozin flüssig. Weed species showed a different sensitivity. There were leaf discoloration, contractions and growth inhibition. In some cases using common practise dose rates of fungicides more than 70% growth inhibition could be estimated 14 days after application in comparison to the untreated control. Effects were much stronger in bioassays than in semi field trials.

Guidelines for management of noxious weeds at Hanford

International Nuclear Information System (INIS)

Roos, R.C.; Malady, M.B.

1995-01-01

Integrated Pest Management Services is responsible for management and control of noxious weeds on the Hanford Site. Weed species and populations are prioritized and objective defined, according to potential site and regional impact. Population controls are implemented according to priority. An integrated approach is planned for noxious weed control in which several management options are considered and implemented separately or in coordination to best meet management objectives. Noxious weeds are inventories and monitored to provide information for planning and program review

Crop characteristics and weed Interactions of diverse Rrecurrent Inbred Lines (RILs) from a weed-suppressive x non-suppressive rice mapping population

Science.gov (United States)

ndica rice genotypes with enhanced weed suppression traits have been previously identified as potentially useful in supplementing weed control efforts in drill-seeded systems in the southern USA. A particularly weed-suppressive indica genotype (PI 312777) that was also high tillering and high yield...

Weed seed germination in winter cereals under contrasting tillage systems

DEFF Research Database (Denmark)

Scherner, Ananda

2015-01-01

to accumulate in the top soil layer and timing of herbicide applications sometimes seems to target the emergence pattern of these weeds poorly. In contrast to the management of most diseases and pests, weed management should be considered in a time frame. The abilities to produce above and below ground...... of weeds. An important component in IWM is to understand and ultimately predict weed emergence patterns in relation to the cropping system and the tillage method applied. A better understanding of the cumulative emergence patterns of weed species in winter crops under different tillage regimes will help......Grass weeds and Gallium aparine are major weed problems in North European arable cropping systems with high proportions of winter crops, especially winter wheat (Clarke et al., 2000; Melander et al., 2008). Problems are accentuated where inverting tillage is omitted, as weed seeds tend...

Emerging Challenges and Opportunities for Education and Research in Weed Science

Directory of Open Access Journals (Sweden)

Bhagirath S. Chauhan

2017-09-01

Full Text Available In modern agriculture, with more emphasis on high input systems, weed problems are likely to increase and become more complex. With heightened awareness of adverse effects of herbicide residues on human health and environment and the evolution of herbicide-resistant weed biotypes, a significant focus within weed science has now shifted to the development of eco-friendly technologies with reduced reliance on herbicides. Further, with the large-scale adoption of herbicide-resistant crops, and uncertain climatic optima under climate change, the problems for weed science have become multi-faceted. To handle these complex weed problems, a holistic line of action with multi-disciplinary approaches is required, including adjustments to technology, management practices, and legislation. Improved knowledge of weed ecology, biology, genetics, and molecular biology is essential for developing sustainable weed control practices. Additionally, judicious use of advanced technologies, such as site-specific weed management systems and decision support modeling, will play a significant role in reducing costs associated with weed control. Further, effective linkages between farmers and weed researchers will be necessary to facilitate the adoption of technological developments. To meet these challenges, priorities in research need to be determined and the education system for weed science needs to be reoriented. In respect of the latter imperative, closer collaboration between weed scientists and other disciplines can help in defining and solving the complex weed management challenges of the 21st century. This consensus will provide more versatile and diverse approaches to innovative teaching and training practices, which will be needed to prepare future weed science graduates who are capable of handling the anticipated challenges of weed science facing in contemporary agriculture. To build this capacity, mobilizing additional funding for both weed research and

Weed flora in organically grown spring cereals in Finland

Directory of Open Access Journals (Sweden)

J. SALONEN

2008-12-01

Full Text Available The weed flora in organically grown spring cereals was investigated in southern and central Finland in 1997-1999 with the primary purpose of determining the species composition and the level of weed infestation. Altogether 165 fields were surveyed in the middle of the growing season. A total of 126 weed species were found, of which 42 exceeded the frequency level of 10%. The most frequent weed species were Chenopodium album, Stellaria media, Galeopsis spp. and Viola arvensis. Elymus repens was the most frequent grass species. The average density of weeds was 469 plants m-2 (median 395, and the air-dry biomass was 678 kg ha-1 (median 567 which accounted for 17% of the total biomass of the crop stand. Infestation by Chenopodium album and the perennial species Elymus repens, Cirsium arvense and Sonchus arvensis is of major concern. Weed control strategies should include direct control measures to overcome weed problems related to the conversion period from conventional to organic growing.

Weeds as important vegetables for farmers

NARCIS (Netherlands)

Cruz Garcia, G.S.; Price, L.L.

2012-01-01

The objective of this study was to investigate the multiple uses and cognitive importance of edible weeds in Northeast Thailand. Research methods included focus group discussions and freelistings. A total of 43 weeds consumed as vegetable were reported, including economic, naturalized, agricultural

Development of Weeds Density Evaluation System Based on RGB Sensor

Science.gov (United States)

Solahudin, M.; Slamet, W.; Wahyu, W.

2018-05-01

Weeds are plant competitors which potentially reduce the yields due to competition for sunlight, water and soil nutrients. Recently, for chemical-based weed control, site-specific weed management that accommodates spatial and temporal diversity of weeds attack in determining the appropriate dose of herbicide based on Variable Rate Technology (VRT) is preferable than traditional approach with single dose herbicide application. In such application, determination of the level of weed density is an important task. Several methods have been studied to evaluate the density of weed attack. The objective of this study is to develop a system that is able to evaluate weed density based on RGB (Red, Green, and Blue) sensors. RGB sensor was used to acquire the RGB values of the surface of the field. An artificial neural network (ANN) model was then used for determining the weed density. In this study the ANN model was trained with 280 training data (70%), 60 validation data (15%), and 60 testing data (15%). Based on the field test, using the proposed method the weed density could be evaluated with an accuracy of 83.75%.

Preliminary results of in vitro propagation of Guayule

Science.gov (United States)

Dastoor, M. N.; Schubert, W. W.; Petersen, G. R.

1981-01-01

Guayule, Parthenium argentatum Gray, was first established in tissue culture by Bonner and Arreguin (1950) as a means to study the effects of various chemicals and extracts on rubber production. The propagation of whole guayule plants from tissue culture, however, has not been accomplished. The reported investigation is concerned with such an objective. In an attempt to stimulate rubber production in Guayule, Yokoyama et al. (1977) sprayed juvenile plants with 2-(3,4-dichloro-phenoxy)triethylamine (TEA derivative). This treatment resulted in increased isoprenoid levels in the plant tissue. In the current investigation, experiments were conducted to study the effect of TEA derivative on in vitro cultures. It was found that a suppression of callus formation occurs at a 10 mg/L concentration of TEA derivative with a resultant increase of shoot formation. Lower and higher concentrations of TEA derivative promote callus formation.

Combustion synthesis of MgO nanoparticles using plant extract: Structural characterization and photoluminescence studies

Energy Technology Data Exchange (ETDEWEB)

Kumar, Danith; Chikkahanumantharayappa [Dept. of Physics, Vivekananda First grade College, Bangalore - 560055 (India); Yadav, L. S. Reddy; Nagaraju, G., E-mail: nagarajugn@rediffmail.com [Dept of Chemistry, Siddaganga Institute of Technology, Tumkur, Karnataka-572103 (India); Lingaraju, K.; Naika, H. Raja [Dept. of Environmental Science, Tumkur University, Tumkur, Karnataka-572103 (India); Manjunath, K. [Centre for Nano and Material Sciences, Jain University, Jakkasandra, Karnataka-562112 (India); Suresh, D. [Dept. of Chemistry, Tumkur University, Tumkur, Karnataka-572103 (India); Prasad, Daruka [Dept. of Physics, BMS Institute of Technology, Bangalore-560064 (India); Nagabhushana, H. [CNR Rao Center for Advanced Materials, Tumkur University, Tumkur, Karnataka-572103 (India); Sharma, S. C. [Chattisgarh Swami Vivekananda Technological University, Bhilai, Chattisgarh-490009 (India)

2015-06-24

Magnesium oxide nanoparticles (MgO Nps) have been successfully synthesized via solution combustion method using Parthenium plant extract as fuel for the first time. Powder X-ray diffraction (PXRD) pattern reveal that product belongs to the cubic phase (Periclase). FTIR spectrum shows the band at 822 cm{sup −1} indicates the formation of cubic periclase MgO. The optical band gap of MgO Nps estimated from UV –Vis spectrum was found to be in the range 5.40–5.45 eV. SEM images showed that, the product is agglomerated and particle in nature. Photoluminescence (PL) studies shows violet emission at 390 nm, blue emission at 470 nm and green emission at 550 nm. MgO Nps shows good photocatalytic activity for the degradation of methylene blue (MB) dye under UV/Sun light irradiation.

Combustion synthesis of MgO nanoparticles using plant extract: Structural characterization and photoluminescence studies

International Nuclear Information System (INIS)

Kumar, Danith; Chikkahanumantharayappa; Yadav, L. S. Reddy; Nagaraju, G.; Lingaraju, K.; Naika, H. Raja; Manjunath, K.; Suresh, D.; Prasad, Daruka; Nagabhushana, H.; Sharma, S. C.

2015-01-01

Magnesium oxide nanoparticles (MgO Nps) have been successfully synthesized via solution combustion method using Parthenium plant extract as fuel for the first time. Powder X-ray diffraction (PXRD) pattern reveal that product belongs to the cubic phase (Periclase). FTIR spectrum shows the band at 822 cm −1 indicates the formation of cubic periclase MgO. The optical band gap of MgO Nps estimated from UV –Vis spectrum was found to be in the range 5.40–5.45 eV. SEM images showed that, the product is agglomerated and particle in nature. Photoluminescence (PL) studies shows violet emission at 390 nm, blue emission at 470 nm and green emission at 550 nm. MgO Nps shows good photocatalytic activity for the degradation of methylene blue (MB) dye under UV/Sun light irradiation

Nutritive valve of some ingrediants from arid zone

Energy Technology Data Exchange (ETDEWEB)

Tejada de Hernadex, I

1976-01-01

Vantress chickens 1 week old were given a standard diet of maize and soya or had 25 or 50% jojoba seed meal (Simondsia chinensis) from which most of the wax had been extracted, with lysine or methionine or both or neither. All diets had 20% protein. All chickens given jojoba for 1 week lost weight. For 3 weeks 15 male Wistar rats 28 days old had 30 or 15% guayule leaves (Parthenium argentatum) to replace lucerne meal wholly or partly. All given guayule lost weight and lesions of kidney, lung, liver and spleen were found. For 4 weeks 30 Wistar rats initially 30 days old got 35% of dietary energy from bastard saffron oil or with 25, 50, 75 or 100% of it replaced by oil from seeds of Yucca filifera. There was no difference in growth or feed conversion among groups.

Mechanical weed control in organic winter wheat

Directory of Open Access Journals (Sweden)

Euro Pannacci

2017-12-01

Full Text Available Three field experiments were carried out in organic winter wheat in three consecutive years (exp. 1, 2005-06; exp. 2, 2006- 07; exp. 3, 2007-08 in central Italy (42°57’ N - 12°22’ E, 165 m a.s.l. in order to evaluate the efficacy against weeds and the effects on winter wheat of two main mechanical weed control strategies: i spring tine harrowing used at three different application times (1 passage at T1, 2 passages at the time T1, 1 passage at T1 followed by 1 passage at T1 + 14 days in the crop sowed at narrow (traditional row spacing (0.15 m; and ii split-hoeing and finger-weeder, alone and combined at T1, in the crop sowed at wider row spacing (0.30 m. At the time T1 winter wheat was at tillering and weeds were at the cotyledons-2 true leaves growth stage. The experimental design was a randomized block with four replicates. Six weeks after mechanical treatments, weed ground cover (% was rated visually using the Braun-Blanquet coverabundance scale; weeds on three squares (0.6×0.5 m each one per plot were collected, counted, weighed, dried in oven at 105°C to determine weed density and weed above-ground dry biomass. At harvest, wheat ears density, grain yield, weight of 1000 seeds and hectolitre weight were recorded. Total weed flora was quite different in the three experiments. The main weed species were: Polygonum aviculare L. (exp. 1 and 2, Fallopia convolvulus (L. Á. Löve (exp. 1 and 3, Stachys annua (L. L. (exp. 1, Anagallis arvensis L. (exp. 2, Papaver rhoeas L. (exp.3, Veronica hederifolia L. (exp. 3. In the winter wheat sowed at narrow rows, 2 passages with spring-tine harrowing at the same time seems to be the best option in order to reconcile a good efficacy with the feasibility of treatment. In wider rows spacing the best weed control was obtained by split hoeing alone or combined with finger-weeder. The grain yield, on average 10% higher in narrow rows, the lower costs and the good selectivity of spring-tine harrowing

Interactions between pre- and post-emergence weed harrowing in spring cereals

DEFF Research Database (Denmark)

Brandsæter, L.O.; Mangerud, K.; Rasmussen, Jesper

2012-01-01

that pre- and post-emergence harrowing interact positively, that a combination gives more stable weed control effects than pre- and post-emergence weed harrowing used alone, and that a harrow type with bent tines is more aggressive and suitable on hard-packed soils than a harrow with strait tines...... the average effect of post-emergence harrowing was 47% on weed density and 41% on weed biomass. The combined effect of pre- and post-emergence weed harrowing was 61% on weed density and 54% on weed biomass. The combination did not give more stable weed control effects than pre- and post-emergence weed...... harrowing used alone. Pre-emergence harrowing increased the average crop yield by 6.2%, post-emergence harrowing by 4.0% and the combined effect was 10%. Crop yield was mainly increased on hard-packed soils. Weed and crop responses varied strongly among experiments, but the efficacy of pre- and post...

Team-up Crop Diversification and Weed Management: PRODIVA

DEFF Research Database (Denmark)

Gerowitt, B.; Melander, B.; Krawczyk, R.

2015-01-01

The research-network PRODIVA focuses on a better utilization of crop diversification for weed management in North European arable cropping systems. The goal is to maintain diverse arable weed vegetation that is manageable in the long-term and could fulfil other necessary systemfunctions including...... support of beneficial organisms. The partners in PRODIVA will synthesize knowledge from terminated and running research projects and set-up selected new experiments on cover crops and variety resp. crop mixtures. Moreover, we will interact with partners from farming practice and extension services...... in organic agriculture. Regional fields will be surveyed for weeds to safeguard the relevance of the experimental research. Current cropping practices and their influence on weed pressure and weed diversity will be identified. The project will involve relevant stakeholders from the participating countries...

The changing role of agriculture and tomorrow's weed research agenda

NARCIS (Netherlands)

Kropff, M.J.; Bastiaans, L.; Kempenaar, C.; Weide, van der R.Y.

2008-01-01

With the changing position of agriculture in the world the challenges for weed management and weed science are changing as well. In this paper recent developments in weed science with respect to several aspects of weed management are discussed in relation to those changes. Developments in cultural

Rounding Up the Astrophysical Weeds

Science.gov (United States)

McMillan, James P.

2016-09-01

New instruments used for astronomy such as ALMA, Herschel, and SOFIA have greatly increased the quality of available astrophysical data. These improved data contain spectral lines and features which are not accounted for in the quantum mechanical (QM) catalogs. A class of molecules has been identified as being particularly problematic, the so-called "weeds". These molecules have numerous transitions, of non-trivial intensity, which are difficult to model due to highly perturbed low lying vibrational states. The inability to properly describe the complete contribution of these weeds to the astrophysical data has led directly to the misidentification of other target molecules. Ohio State's Microwave Laboratory has developed an alternative approach to this problem. Rather than relying on complex QM calculations, we have developed a temperature dependent approach to laboratory based terahertz spectroscopy. We have developed a set of simple packages, in addition to traditional line list catalogs, that enable astronomers to successfully remove the weed signals from their data. This dissertation will detail my laboratory work and analysis of three keys weeds: methanol, methyl formate and methyl cyanide. Also, discussed will be the analytical technique I used to apply these laboratory results to astrophysical data.

The Power and Potential of Genomics in Weed Biology and Management.

Science.gov (United States)

Ravet, Karl; Patterson, Eric L; Krähmer, Hansjörg; Hamouzová, Kateřina; Fan, Longjiang; Jasieniuk, Marie; Lawton-Rauh, Amy; Malone, Jenna M; Scott McElroy, J; Merotto, Aldo; Westra, Philip; Preston, Christopher; Vila-Aiub, Martin M; Busi, Roberto; Tranel, Patrick J; Reinhardt, Carl; Saski, Christopher; Beffa, Roland; Neve, Paul; Gaines, Todd A

2018-04-24

There have been previous calls for, and efforts focused on, realizing the power and potential of weed genomics for better understanding of weeds. Sustained advances in genome sequencing and assembly technologies now make it possible for individual research groups to generate reference genomes for multiple weed species at reasonable costs. Here, we present the outcomes from several meetings, discussions, and workshops focused on establishing an International Weed Genomics Consortium (IWGC) for a coordinated international effort in weed genomics. We review the 'state of the art' in genomics and weed genomics, including technologies, applications, and on-going weed genome projects. We also report the outcomes from a workshop and a global survey of the weed science community to identify priority species, key biological questions, and weed management applications that can be addressed through greater availability of, and access to, genomic resources. Major focus areas include the evolution of herbicide resistance and weedy traits, the development of molecular diagnostics, and the identification of novel targets and approaches for weed management. There is increasing interest in, and need for, weed genomics, and the establishment of the IWGC will provide the necessary global platform for communication and coordination of weed genomics research. This article is protected by copyright. All rights reserved.

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.

Image-based thresholds for weeds in maize fields

DEFF Research Database (Denmark)

Asif, Ali; Streibig, Jens Carl; Christensen, Svend

2015-01-01

in some parts of the field and if late germinating weeds do not affect yield, it may not be necessary the spray such places from an economic point of view. Consequently, it makes sense to develop weed control thresholds for patch spraying, based on weed cover early in the growing season. In Danish maize...

of different weed control methods on Weed infestation, growth

African Journals Online (AJOL)

thinkexploitsint'l

This weed control method also resulted in significantly better growth and ... proper management, it is possible to obtain 2,500 kg ha-1 (Onwueme and Sinha, 1991). ... however, time consuming, labour – intensive, strenuous and generally ...

Weeds Cause Losses in Field Crops through Allelopathy

Directory of Open Access Journals (Sweden)

Ali ZOHAIB

2016-03-01

Full Text Available A large number of weeds are known to be associated with crops and causing economic losses. Weeds interfere with crops through competition and allelopathy. They produce secondary metabolites known as allelochemicals, which belong to numerous chemical classes such as phenolics, alkaloids, fatty acids, indoles, terpens etc. However, phenolics are the predominant class of allelochemicals. The allelochemicals release from weed plants takes place through leaf leachates, decomposition of plant residues, volatilization and root exudates. Weeds leave huge quantities of their residues in field and affect the associated, as well as succeeding crops, in various cropping systems. Liberation of allelochemicals from weeds affects the germination, stand establishment, growth, yield and physiology of crop plants. They cause substantial reduction in germination and growth of the crop plants by altering various physiological processes such as enzyme activity, protein synthesis, photosynthesis, respiration, cell division and enlargement, which ultimately leads to a significant reduction in crop yield. In crux, allelopathic weeds represent a potential threat for crop plants and cause economic losses.

Evaluation of yield quality and weed infestation of common valerian (Valeriana officinalis L. in dependence on weed control method and forecrop.

Directory of Open Access Journals (Sweden)

Cezary Kwiatkowski

2012-12-01

Full Text Available A field experiment involving the cultivation of common valerian was conducted on loess soil in Abramów (Lublin region in the period 2007-2009. Qualitative parameters of herbal raw material obtained from this plant as well as in-crop weed infestation were evaluated depending on the protection method and forecrop. Hand-weeded plots, in which a hand hoe was used, were the control. In the other treatments, weeds were controlled using various herbicides and a mechanical implement (brush weeder. Potato and winter wheat + field pea cover crop were the forecrops for common valerian crops. A hypothesis was made that the use of a brush weeder and herbicides not registered for application in valerian crops would have a positive effect on this plant's productivity and weed infestation in its crops. It was also assumed that the introduction of a cover crop would allow the elimination of differences in the forecrop value of the crop stands in question. The best quantitative and qualitative parameters of common valerian raw material as well as the largest reduction of incrop weed infestation were recorded after the application of the herbicides which were not type approved. The use of the brush weeder in the interrows also had a beneficial effect on productivity of the plant in question, but secondary weed infestation at the end of the growing season of common valerian turned out to be its disadvantage. Traditional crop protection methods used in common valerian crops were less effective in weed infestation reduction and they resulted in lower plant productivity and raw material quality. Potato proved to be a better forecrop for common valerian than winter wheat + field pea; however, this positive effect was not confirmed statistically. The following annual weeds: Chenopodium album, Galinsoga parviflora, Stellaria media, were predominant in the common valerian crop. Traditional weed control methods resulted in the dominance of some dicotyledonous weeds, such

Weed identification using an automated active shape matching (AASM) technique

DEFF Research Database (Denmark)

C. Swain, Kishore; Nørremark, Michael; Jørgensen, Rasmus Nyholm

2011-01-01

Weed identification and control is a challenge for intercultural operations in agriculture. As an alternative to chemical pest control, a smart weed identification technique followed by mechanical weed control system could be developed. The proposed smart identification technique works on the con......Weed identification and control is a challenge for intercultural operations in agriculture. As an alternative to chemical pest control, a smart weed identification technique followed by mechanical weed control system could be developed. The proposed smart identification technique works...... on the concept of ‘active shape modelling’ to identify weed and crop plants based on their morphology. The automated active shape matching system (AASM) technique consisted of, i) a Pixelink camera ii) an LTI (Lehrstuhlfuer technische informatik) image processing library, iii) a laptop pc with the Linux OS. A 2...

Precise tillage systems for enhanced non-chemical weed management

NARCIS (Netherlands)

Kurstjens, D.A.G.

2007-01-01

Soil and residue manipulation can assist weed management by killing weeds mechanically, interfering in weed lifecycles, facilitating operations and enhancing crop establishment and growth. Current tillage systems often compromise these functions, resulting in heavy reliance on herbicides,

Seeding method and rate influence on weed suppression in aerobic ...

African Journals Online (AJOL)

High weed pressure is amongst the major constraints to the extensive adoption of aerobic rice system as a water-wise technique. Towards developing a sustainable weed management strategy, seeding method and rate may substantially contribute to weed suppression and reduce herbicide use and weeding cost. A trough ...

Wallowa Canyonlands Weed Partnership : Completion Report November 19, 2009

Energy Technology Data Exchange (ETDEWEB)

Porter, Mark C.; Ketchum, Sarah

2008-12-30

Noxious weeds threaten fish and wildlife habitat by contributing to increased sedimentation rates, diminishing riparian structure and function, and reducing forage quality and quantity. Wallowa Resources Wallowa Canyonlands Partnership (WCP) protects the unique ecological and economic values of the Hells Canyon grasslands along lower Joseph Creek, the lower Grande Ronde and Imnaha Rivers from invasion and degradation by noxious weeds using Integrated Weed Management techniques. Objectives of this grant were to inventory and map high priority weeds, coordinate treatment of those weeds, release and monitor bio-control agents, educate the public as to the dangers of noxious weeds and how to deal with them, and restore lands to productive plant communities after treatment. With collaborative help from partners, WCP inventoried {approx} 215,000 upland acres and 52.2 miles of riparian habitat, released bio-controls at 23 sites, and educated the public through posters, weed profiles, newspaper articles, and radio advertisements. Additionally, WCP used other sources of funding to finance the treatment of 1,802 acres during the course of this grant.

BIOLOGICAL CONTROL OF WEEDS BY MEANS OF PLANT PATHOGENS

Directory of Open Access Journals (Sweden)

Marija Ravlić

2014-06-01

Full Text Available Biological control is the use of live beneficial organisms and products of their metabolism in the pests control. Plant pathogens can be used for weed control in three different ways: as classical, conservation and augmentative (inoculative and inundated biological control. Inundated biological control involves the use of bioherbicides (mycoherbicides or artificial breeding of pathogens and application in specific stages of crops and weeds. Biological control of weeds can be used where chemical herbicides are not allowed, if resistant weed species are present or in the integrated pest management against weeds with reduced herbicides doses and other non-chemical measures, but it has certain limitations and disadvantages.

Cover crop-based ecological weed management: exploration and optimization

NARCIS (Netherlands)

Kruidhof, H.M.

2008-01-01

Keywords: organic farming, ecologically-based weed management, cover crops, green manure, allelopathy, Secale cereale, Brassica napus, Medicago sativa

Cover crop-based ecological weed management: exploration and optimization. In organic farming systems, weed control is recognized as one

Evaluation of multi-species weed competition and weeds population dynamic in corn Zea mays L. field

Directory of Open Access Journals (Sweden)

S Mijani

2016-05-01

Full Text Available In order to examine the multi-species weed competition in corn field an experiment as an interval mapping was carried out at the Agricultural Research field of Ferdowsi University of Mashhad during growing season 2009-2010. At 3-4 leafy stages of corn, 20 non-destructive quadrates determine and the density of weeds was counted separately. At the same time, 20 destructive quadrates determine and in addition of counting number of plants, leaf area index and dry weight of each species were recorded separately. By using data from previous section, hyperbolic functions were fitted. In these functions number of species serve as the independent variable, weight or leaf area was considered as the dependent variable. With the help of these functions and leaf dry weight of each species was determined for non-destructive quadrates at this stage. Relative leaf area at early season as independent variables and natural logarithm of individual plant weight at later season as dependent variable in a multiple linear regression was fitted to obtain the interspecies competition coefficients. Based on ln of weight of single plant equation the weed interference effects on the corn yield can be divided into two groups: inhibition (negative sign and stimulation (positive sign. Among all weeds, night shade (Solanum nigrum L., redroot pigweed (Amaranthus retroflexus L. and lambsquarter (Chenopodium album L. had positive effects on corn yield, respectively. In fact, these weeds had competition and negative impacts on other weeds and reduced their competition power with corn and caused facilitation role on corn yield. At the end of growing season of corn, population of lambsquarter and Common purslane (Portulaca oleracea L. decreased while population of barnyard grass(Echinochloa crus-galli L., redroot pigweed and night shade increased.

Estimating economic thresholds for site-specific weed control using manual weed counts and sensor technology: an example based on three winter wheat trials.

Science.gov (United States)

Keller, Martina; Gutjahr, Christoph; Möhring, Jens; Weis, Martin; Sökefeld, Markus; Gerhards, Roland

2014-02-01

Precision experimental design uses the natural heterogeneity of agricultural fields and combines sensor technology with linear mixed models to estimate the effect of weeds, soil properties and herbicide on yield. These estimates can be used to derive economic thresholds. Three field trials are presented using the precision experimental design in winter wheat. Weed densities were determined by manual sampling and bi-spectral cameras, yield and soil properties were mapped. Galium aparine, other broad-leaved weeds and Alopecurus myosuroides reduced yield by 17.5, 1.2 and 12.4 kg ha(-1) plant(-1)  m(2) in one trial. The determined thresholds for site-specific weed control with independently applied herbicides were 4, 48 and 12 plants m(-2), respectively. Spring drought reduced yield effects of weeds considerably in one trial, since water became yield limiting. A negative herbicide effect on the crop was negligible, except in one trial, in which the herbicide mixture tended to reduce yield by 0.6 t ha(-1). Bi-spectral cameras for weed counting were of limited use and still need improvement. Nevertheless, large weed patches were correctly identified. The current paper presents a new approach to conducting field trials and deriving decision rules for weed control in farmers' fields. © 2013 Society of Chemical Industry.

Influence of cowpea and melon populations on weed infestation and ...

African Journals Online (AJOL)

Small farmers in the humid regions of tropical Africa spend 30–42% of their total farm labour input in controlling weeds. Chemical weed control is normally recommended but high cost of herbicides and environmental pollution are specific problems with chemical weed control. A three year bio-weed control system with three ...

Chemical Weed Control in Saffron (Crocus sativus Fields

Directory of Open Access Journals (Sweden)

majid abbaspoor

2018-01-01

Full Text Available Introduction Saffron is derived from the stigmas of the saffron (Crocus sativus L. It is the world’s most expensive spice and has been widely used in many countries. It is also increasingly used for medicinal purposes. Weed control in this perennial, small and low growing crop, needs a lot of labor work. Chemical approach is one of the most effective methods for weed control in saffron. Currently, some herbicide options are available for applications in saffron. For example, satisfactory broadleaved weed control would be achieved by post-emergence application of metribuzin and ioxynil after harvesting saffron flowers. Application of glyphosate and/or 2, 4-D / 2, 4-DB are used to clean up the beds prior to the new season’s flowering and growth of saffron in New Zealand. The selective weed control of weeds in saffron has not been widely reported elsewhere but some in Iran. The choice of herbicide(s depends on the kind of weeds present. In some literatures metribuzin showed promising results for weed control in saffron fields. It is selectively used for control of annual grasses and numerous broad-leaved weeds. The objective of this study was the evaluation of the efficacy of 15 herbicides with different mode of actions, selected on the basis of dominant weed flora and previous studies, on weeds grown in saffron fields. Materials and Methods A field study was conducted to evaluate the efficacy of herbicides for weed control in saffron (Crocus sativus in Agricultural and Natural Resources Research and Education Center of Khorasan Razavi Province, Mashhad, in 2014-2015 growing season. The experiment was conducted in a completely randomized block design with three replications. Treatments were consisted of metsulfuron-methyl + sulfosulfuron (Total® at dose of 40 g ha-1, sulfosulfuron (Apirus® at dose of 26.6 g ha-1, oxadiazon (Ronestar® at dose of 2 l ha-1, oxyflurofen (Goal® at dose of 2 l ha-1, mesosulfuron + idosulfuron + diflufenican

Can Arbuscular Mycorrhizal Fungi Reduce the Growth of Agricultural Weeds?

Science.gov (United States)

Veiga, Rita S. L.; Jansa, Jan; Frossard, Emmanuel; van der Heijden, Marcel G. A.

2011-01-01

Background Arbuscular mycorrhizal fungi (AMF) are known for their beneficial effects on plants. However, there is increasing evidence that some ruderal plants, including several agricultural weeds, respond negatively to AMF colonization. Here, we investigated the effect of AMF on the growth of individual weed species and on weed-crop interactions. Methodology/Principal Findings First, under controlled glasshouse conditions, we screened growth responses of nine weed species and three crops to a widespread AMF, Glomus intraradices. None of the weeds screened showed a significant positive mycorrhizal growth response and four weed species were significantly reduced by the AMF (growth responses between −22 and −35%). In a subsequent experiment, we selected three of the negatively responding weed species – Echinochloa crus-galli, Setaria viridis and Solanum nigrum – and analyzed their responses to a combination of three AMF (Glomus intraradices, Glomus mosseae and Glomus claroideum). Finally, we tested whether the presence of a crop (maize) enhanced the suppressive effect of AMF on weeds. We found that the growth of the three selected weed species was also reduced by a combination of AMF and that the presence of maize amplified the negative effect of AMF on the growth of E. crus-galli. Conclusions/Significance Our results show that AMF can negatively influence the growth of some weed species indicating that AMF have the potential to act as determinants of weed community structure. Furthermore, mycorrhizal weed growth reductions can be amplified in the presence of a crop. Previous studies have shown that AMF provide a number of beneficial ecosystem services. Taken together with our current results, the maintenance and promotion of AMF activity may thereby contribute to sustainable management of agroecosystems. However, in order to further the practical and ecological relevance of our findings, additional experiments should be performed under field conditions. PMID

Focus on ecological weed management : what is hindering adoption?

NARCIS (Netherlands)

Bastiaans, L.; Paolini, R.; Baumann, D.T.

2008-01-01

Despite increased concerns regarding the heavy reliance of many cropping systems on chemical weed control, adoption of ecological weed management practices is only steadily progressing. For this reason, this paper reflects on both the possibilities and limitations of cultural weed control practices.

Water management as a key component of integrated weed management

Directory of Open Access Journals (Sweden)

Antonio Berti

2010-09-01

Full Text Available Water management within the cropping system is a key factor for an integrated weed management. Soil moisture affects seed persistence and seed dormancy, thus influencing their germination, the establishment of seedlings as well as the competition at adult stage and the number, vitality and dormancy of the new seeds produced by the weeds. The interactions among water availability and competition are very complex and still not fully understood. A research effort in this sector should the be very relevant for the development of new approaches of weed management, such as “Ecological weed management”, aiming to reduce weed density and competitiveness and, in the medium term, to prevent undesired modifications of the weed flora.

Biological Efficacy of Herbicides for Weed Control in Noncropped Areas

Directory of Open Access Journals (Sweden)

Tsvetanka Dimitrova

2009-01-01

Full Text Available An increasing problem facing agricultural producers is the invasion of weeds, perennial in particular, so that implementation of industrial technologies is impossible without their highly efficient and rational control. For the purpose of studying efficient herbicides for weed control in noncropped areas (stubbles, a biological study of five total systemic herbicides was conducted in areas under natural weed infestation and pressure from othersurrounding weeds at the Institute of Forage Crops in Pleven in 2005-2007. The trials were carried out in field conditions using the block method with plot size of 20 m². Treatment was conducted at the predominant stage of budding of perennial dicotyledonous weeds and earing of monocotyledonous weeds. Herbicidal efficacy was recorded on the EWRS 9-score scale (0-100% killed weeds = score 9-1. It was found that treatment of noncropped areas (stubbles with the total systemic herbicides Touchdown System 4 (360 g/l glyphosate; Cosmic (360 g/l glyphosate; Roundup Plus (441 g/l glyphosate potassium salt; Leon 36 SL (360 g/l glyphosate and Glyphos Super 45 SL (450 g/l glyphosate was highly efficient, so that it was a successful element of a strategy for controlling weeds of different biological groups, and was especially effective against perennial weeds.

Weeds and ground-dwelling predators' response to two different weed management systems in glyphosate-tolerant cotton: A farm-scale study.

Science.gov (United States)

García-Ruiz, Esteban; Loureiro, Íñigo; Farinós, Gema P; Gómez, Pablo; Gutiérrez, Elena; Sánchez, Francisco Javier; Escorial, María Concepción; Ortego, Félix; Chueca, María Cristina; Castañera, Pedro

2018-01-01

The use of glyphosate, as a post-emergence broad-spectrum herbicide in genetically modified glyphosate-tolerant (GT) cotton, supposes a big change in weed management programs with respect to a conventional regime. Thus, alterations in arable flora and arthropod fauna must be considered when evaluating their potential impacts. A 3-year farm-scale study was conducted in a 2-ha GT cotton crop, in southern Spain, to compare the effects of conventional and glyphosate herbicide regimes on weed abundance and diversity and their consequences for ground-dwelling predators. Surveys reveal that weed density was relatively low within all treatments with a few dominant species, with significantly higher weed densities and modifications of the floristic composition in glyphosate-treated plots that led to an increase in the abundance of Portulaca oleracea and to a reduction in plant diversity. The activity-density of the main predatory arthropod taxa (spiders, ground beetles, rove beetles and earwigs) varied among years, but no significant differences were obtained between conventional and glyphosate herbicide regimes. However, significant differences between treatments were obtained for ground beetles species richness and diversity, being higher under the glyphosate herbicide regime, and a positive correlation with weed density could be established for both parameters. The implications of these findings to weed control in GT cotton are discussed.

RNAseq reveals weed-induced PIF3-like as a candidate target to manipulate weed stress response in soybean

NARCIS (Netherlands)

Horvath, David P; Hansen, Stephanie A; Moriles-Miller, Janet P; Pierik, Ronald; Yan, Changhui; Clay, David E; Scheffler, Brian; Clay, Sharon A

Weeds reduce yield in soybeans (Glycine max) through incompletely defined mechanisms. The effects of weeds on the soybean transcriptome were evaluated in field conditions during four separate growing seasons. RNASeq data were collected from six biological samples of soybeans growing with or without

Evaluation of mulching materials as integrated weed management component in maize crop

International Nuclear Information System (INIS)

Shah, F.U.

2014-01-01

Yield losses by weeds in maize crop and demonstrated efficacy of various mulches in weed management led to check the efficacy of various available mulches for suppressing weeds in maize crop at National Agricultural Research Centre (NARC), Islamabad during kharif (autumn) season 2011. The experiment was laid in Randomized Complete Block Design, (RBCD) having eight treatments and four replications. The treatments were black plastic, white plastic, sugarcane straw, wheat straw, live mulch, weeds as mulch, hand weeding and weedy check. Weed data included weed density m, fresh and dry weight g m, while crop data included crop density m, fresh and dry weight g m, number of plant plot, stover yield (g), plant height (cm), number of cobs plant, number of leaves plant, average grain number of five cobs and grain yield (t ha). With the exception of hand weeding, minimum number of weeds 128 m and 164 m were recorded in black plastic and weeds as mulch, respectively, compared to 595 min weedy check. Similarly, maximum grain yields (1.91 and 1.85 tha) were recorded in black plastic and weeds as mulch, while minimum grain yield (0.64 t ha) was recorded in weedy check plots. The economic net returns of black plastic mulch and weeds as mulch were Rs. 39,824 and Rs. 38,291, respectively as compared to Rs. 21431 for weedy check. Yield increased by 21.1 and 16.5% over hand weeding by plastic mulch and weeds as mulch, respectively. Black plastic followed by weeds as mulch, are recommended to control weeds and get maximum yield as well as net economic return. (author)

Weed suppression ability of spring barley varieties

DEFF Research Database (Denmark)

Christensen, Svend

1995-01-01

, Grit. Ranking varietal responses to weed competition in terms of grain yield loss corresponded well to ranking weed dry matter produced in crop weed mixtures. There was no correspondence between the varietal grain yields in pure stands and their competitiveness, suggesting that breeding to optimize...... both yielding and competitive ability may be possible. Non-linear regression models were fitted to canopy height and light interception data for each variety in all three years. The canopy height model provided a precise description of development and maximum canopy height of the varieties. A light...

The weeding handbook a shelf-by-shelf guide

CERN Document Server

Vnuk, Rebecca

2015-01-01

"No! We can't rid of that!" Vnuk, author of the popular "Weeding Tips" column on Booklist Online, is here to show you that yes, you can. A library is an ever-changing organism; when done the right way, weeding helps a library thrive by focusing its resources on those parts of the collection that are the most useful to its users. Her handbook takes the guesswork out of this delicate but necessary process, giving public and school library staff the knowledge and the confidence to effectively weed any collection, of any size. Going through the proverbial stacks shelf by shelf, Vnuk: Explains why weeding is important for a healthy library, demonstrating that a vibrant collection leads to robust circulation, which in turn affects library budgets Walks readers through a library's shelves by Dewey area, with recommended weeding criteria and call-outs in each area for the different considerations of large collections and smaller collections Features a chapter addressing reference, media, magazines and newspapers, e-b...

Weed Mapping with Co-Kriging Using Soil Properties

DEFF Research Database (Denmark)

Heisel, Torben; Ersbøll, Annette Kjær; Andreasen, Christian

1999-01-01

Our aim is to build reliable weed maps to control weeds in patches. Weed sampling is time consuming but there are some shortcuts. If an intensively sampled variable (e.g. soil property) can be used to improve estimation of a sparsely sampled variable (e.g. weed distribution), one can reduce weed...... sampling. The geostatistical estimation method co-kriging uses two or more sampled variables, which are correlated, to improve the estimation of one of the variables at locations where it was not sampled. We did an experiment on a 2.1 ha winter wheat field to compare co-kriging using soil properties......, with kriging based only on one variable. The results showed that co-kriging Lamium spp. from 96 0.25m2 sample plots ha-1 with silt content improved the prediction variance by 11% compared to kriging. With 51 or 18 sample plots ha-1 the prediction variance was improved by 21 and 15%....

Problems and achievements of cotton (Gossypium Hirsutum L. weeds control

Directory of Open Access Journals (Sweden)

T. Barakova

2017-09-01

Full Text Available Abstract. Weed control in the cultivation of cotton is critical to the yield and quality of production. The influence of economically important weeds was studied. Chemical control is the most effective method of weed control in cotton but much of the information on it relates to primary weed infestation. Problems with primary weed infestation in cotton have been solved to a significant extent. The question of secondary weed infestation with annual and perennial graminaceous weeds during the period of cotton vegetation is also determined largely by the use of antigraminaceous herbicides. The data related to herbicides to effectively control secondary germinated broadleaf weeds in conventional technology for cotton growing are quite scarce, even globally. We are still seeking effective herbicides for control of these weeds in cotton crops. Studies on their influence on the sowing characteristics of cotton seed and the quality of cotton fiber are still insufficient. In the scientific literature there is not enough information on these questions. The combinations of herbicides, as well as their tank mixtures with fertilizers or plant growth regulators are more efficient than autonomous application. Often during their combined application higher synergistic effect on yield is produced. There is information about cotton cultivars resistant to glyphosate. These cultivars are GMO and they are banned within the European Union, including Bulgaria.

Dynamics of weed populations : spatial pattern formation and implications for control

NARCIS (Netherlands)

Wallinga, J.

1998-01-01

Modelling studies were carried out to analyse spatio-temporal dynamics of annual weed populations and to identify the key factors that determine the long-term herbicide use of weed control programmes. Three different weed control programmes were studied.

In the first weed

Analysis of the Heterogeneity of Weed Infestation in Cereal Stands

Directory of Open Access Journals (Sweden)

Jan Winkler

2015-01-01

Full Text Available The aim of this study was to evaluate the heterogeneity of the incidence of individual weed species on a selected experimental field. This field was situated in the cadastre of the village Žabčice (South Moravian Region, Czech Republic. To evaluate the intensity of weed infestation, a field experiment was established. In 2011, altogether 33 weed species were identified in a stand of spring barley. In the next year, the total number of weeds in a stand of winter wheat was 22. Basing on results of the evaluation of infestation heterogeneity it was possible to detect the following trends: The first one concerned the incidence of significantly dominant species Chenopodium album and Veronica hederifolia in stands of spring barley and winter wheat, respectively. The second one expressed the incidence of the so-called sub-dominant species. Regarding the character of the incidence of these weed species it would be suitable to kill them by means of a targeted application of herbicides. Finally, the third trend concerned the incidence of that group of weeds that occurred in the major part of the experimental plot but in low numbers only. The abundance of these species was minimal and the total number of weed plants did not exceed the limit of 100 specimens. This group of weeds involved also those species that were markedly more frequent on plots situated closer to the margin of the experimental field. The targeted application of herbicides can be performed on plots with a lower level of weed infestation; another possibility, however, seems to be a targeted intervention that helps to control the incidence of a certain weed species and/or that is performed along the margin of the field where the different weed species are more frequent.

High-residue cultivation timing impact on organic no-till soybean weed management

Science.gov (United States)

A cereal rye cover crop mulch can suppress summer annual weeds early in the soybean growing season. However, a multi-tactic weed management approach is required when annual weed seedbanks are large or perennial weeds are present. In such situations, the weed suppression from a cereal rye mulch can b...

Weed Growth Stage Estimator Using Deep Convolutional Neural Networks

DEFF Research Database (Denmark)

Teimouri, Nima; Dyrmann, Mads; Nielsen, Per Rydahl

2018-01-01

This study outlines a new method of automatically estimating weed species and growth stages (from cotyledon until eight leaves are visible) of in situ images covering 18 weed species or families. Images of weeds growing within a variety of crops were gathered across variable environmental conditi...... in estimating the number of leaves and 96% accuracy when accepting a deviation of two leaves. These results show that this new method of using deep convolutional neural networks has a relatively high ability to estimate early growth stages across a wide variety of weed species....

Herbicide-resistant crops: utilities and limitations for herbicide-resistant weed management.

Science.gov (United States)

Green, Jerry M; Owen, Micheal D K

2011-06-08

Since 1996, genetically modified herbicide-resistant (HR) crops, particularly glyphosate-resistant (GR) crops, have transformed the tactics that corn, soybean, and cotton growers use to manage weeds. The use of GR crops continues to grow, but weeds are adapting to the common practice of using only glyphosate to control weeds. Growers using only a single mode of action to manage weeds need to change to a more diverse array of herbicidal, mechanical, and cultural practices to maintain the effectiveness of glyphosate. Unfortunately, the introduction of GR crops and the high initial efficacy of glyphosate often lead to a decline in the use of other herbicide options and less investment by industry to discover new herbicide active ingredients. With some exceptions, most growers can still manage their weed problems with currently available selective and HR crop-enabled herbicides. However, current crop management systems are in jeopardy given the pace at which weed populations are evolving glyphosate resistance. New HR crop technologies will expand the utility of currently available herbicides and enable new interim solutions for growers to manage HR weeds, but will not replace the long-term need to diversify weed management tactics and discover herbicides with new modes of action. This paper reviews the strengths and weaknesses of anticipated weed management options and the best management practices that growers need to implement in HR crops to maximize the long-term benefits of current technologies and reduce weed shifts to difficult-to-control and HR weeds.

Crescimento e metabolismo em artemísia em função do nível de irradiância Growth and metabolism of feverfew plants in response to the irradiance level

Directory of Open Access Journals (Sweden)

Luciana M de Carvalho

2006-09-01

Full Text Available Artemísia [Tanacetum parthenium (L. Schultz-Bip.] é uma planta medicinal fortemente aromática, cujo princípio ativo característico é a lactona sesquiterpênica partenolídeo. Entre os fatores que afetam o cultivo das plantas medicinais destaca-se a irradiância luminosa. O presente trabalho teve por objetivo verificar efeitos de três níveis de irradiância luminosa (730, 523 e 382 µmol de fótons m-2 s-1 na altura, área foliar, número de folhas, teor de açúcares, de amido e de partenolídeo em artemísia. As plantas cresceram a pleno sol e com 30 e 50% de redução na irradiância por 105 dias. A redução na irradiância foi obtida por meio de sombreamento artificial, com a utilização de telas de polietileno pretas. A redução na irradiância incidente causou aumento na altura e na área foliar total de cada planta, mas não alterou o número de folhas. Houve diminuição nos teores de açúcares e de amido em função do sombreamento, mas os teores de partenolídeo não foram alterados significativamente.Feverfew [Tanacetum parthenium (L. Schultz-Bip.] is a strongly aromatic medicinal plant, whose active principle is the sesquiterpene lactone parthenolide. Irradiance ranks among the most important factors that affect growth of medicinal plants. The effect of three irradiance levels (730, 523 and 382 µmol of fotons m-2 s-1 were assessed on feverfew plants height, leaf area, and leaf number, as well as on the contents of sugar, starch, and parthenolide. Plants grew on full sunshine and under 30 and 50% of irradiance reduction, for 105 days. Irradiance was controlled by shadowing plants with a black polyethylene screen. Reduction on irradiance increased plant height and total leaf area, but had no effect on leaf number. A reduction in sugar and starch contents in association with shadowing was observed. Nevertheless, shadowing did not affect significantly the parthenolide content.

Ethnomedicines used in Trinidad and Tobago for reproductive problems.

Science.gov (United States)

Lans, Cheryl

2007-03-15

Throughout history women have tried to control or enhance their fertility using herbal remedies, with various levels of societal support. Caribbean folk medicine has been influenced by European folk medicine, either through the early Spanish and French settlers or through the continuous immigration of Spanish-speaking peoples from Venezuela. Some folk uses are ancient and were documented by Galen and Pliny the Elder. Thirty respondents, ten of whom were male were interviewed from September 1996 to September 2000. The respondents were obtained by snowball sampling, and were found in thirteen different sites, 12 in Trinidad (Paramin, Talparo, Sangre Grande, Mayaro, Carapichaima, Kernahan, Newlands, Todd's Road, Arima, Guayaguayare, Santa Cruz, Port of Spain and Siparia) and one in Tobago (Mason Hall). Snowball sampling was used because there was no other means of identifying respondents and to cover the entire islands. The validation of the remedies was conducted with a non-experimental method. Plants are used for specific problems of both genders. Clusea rosea, Urena sinuata and Catharanthus roseus are used for unspecified male problems. Richeria grandis and Parinari campestris are used for erectile dysfunction. Ageratum conyzoides, Scoparia dulcis, Cucurbita pepo, Cucurbita maxima, Gomphrena globosa and Justicia pectoralis are used for prostate problems. The following plants are used for childbirth and infertility: Mimosa pudica, Ruta graveolens, Abelmoschus moschatus, Chamaesyce hirta, Cola nitida, Ambrosia cumanenesis, Pilea microphylla, Eryngium foetidum, Aristolochia rugosa, Aristolochia trilobata, Coleus aromaticus, Laportea aestuans and Vetiveria zizanioides. The following plants are used for menstrual pain and unspecified female complaints: Achyranthes indica, Artemisia absinthium, Brownea latifolia, Eleutherine bulbosa, Hibiscus rosa-sinensis, Eupatorium macrophyllum, Justicia secunda, Parthenium hysterophorus, Wedelia trilobata, Abelmoschus moschatus

Weeds and ground-dwelling predators′ response to two different weed management systems in glyphosate-tolerant cotton: A farm-scale study

Science.gov (United States)

Farinós, Gema P.; Gómez, Pablo; Gutiérrez, Elena; Sánchez, Francisco Javier; Escorial, María Concepción; Ortego, Félix; Chueca, María Cristina; Castañera, Pedro

2018-01-01

The use of glyphosate, as a post-emergence broad-spectrum herbicide in genetically modified glyphosate-tolerant (GT) cotton, supposes a big change in weed management programs with respect to a conventional regime. Thus, alterations in arable flora and arthropod fauna must be considered when evaluating their potential impacts. A 3-year farm-scale study was conducted in a 2-ha GT cotton crop, in southern Spain, to compare the effects of conventional and glyphosate herbicide regimes on weed abundance and diversity and their consequences for ground-dwelling predators. Surveys reveal that weed density was relatively low within all treatments with a few dominant species, with significantly higher weed densities and modifications of the floristic composition in glyphosate-treated plots that led to an increase in the abundance of Portulaca oleracea and to a reduction in plant diversity. The activity-density of the main predatory arthropod taxa (spiders, ground beetles, rove beetles and earwigs) varied among years, but no significant differences were obtained between conventional and glyphosate herbicide regimes. However, significant differences between treatments were obtained for ground beetles species richness and diversity, being higher under the glyphosate herbicide regime, and a positive correlation with weed density could be established for both parameters. The implications of these findings to weed control in GT cotton are discussed. PMID:29351549

Weed species diversity in organic and integrated farming systems

Directory of Open Access Journals (Sweden)

Magdalena Jastrzębska

2013-10-01

Full Text Available Phytosociological data were collected in 1994–1996 in plots (relevés at the Research Station for Organic Farming and Conservation Breeding of the Polish Academy of Sciences in Popielno included in a large-area experiment conducted according to the concept and method proposed by Prof. S. Nawrocki. In a four-field crop rotation (root crops – spring barley undersown with red clover and grasses – red clover/grass mixture – winter triticale, each field was divided into two management units, organic and integrated. Data were collected in relevés by the Braun-Blanquet method, each year at the peak of the growing season. Weed abundance (% cover in cultivated fields and the number of weed species (species richness in crops were determined, which provided a basis for calculating the Shannon-Wiener indices of species diversity and evenness, and the Rényi profiles. The qualitative (species and quantitative structure of weed communities was compared using the Sørensen index. A total of 115 weed taxa (species, subspecies and varieties were identified in the examined agro-phytocenoses. Echinochloa crus-galli, Chenopodium album, Matricaria maritima subsp. inodora, Capsella bursa-pastoris, Thlaspi arvense and Stellaria media were the most abundant. Weed infestation was slightly higher in the organic farming system than in the integrated system. Organic farming contributed to higher weed species diversity in root crops, red clover/grass mixtures and winter triticale. Weed species richness was reduced in red clover/grass stands, while root crops and – to a lesser degree – spring barley undersown with red clover and grasses decreased weed species diversity. The species composition and in particular the quantitative structure of weeds were affected by crop species and cultivation regime rather than by the farming system. Weed communities of crops grown under organic and integrated farming systems were more similar with regard to species composition

[Spatial and temporal dynamics of the weed community in the Zoysia matrella lawn].

Science.gov (United States)

Liu, Jia-Qi; Li, You-Han; Zeng, Ying; Xie, Xin-Ming

2014-02-01

The heterogeneity of species composition is one of the main attributes in weed community dynamics. Based on species frequency and power law, this paper studied the variations of weed community species composition and spatial heterogeneity in a Zoysia matrella lawn in Guangzhou at different time. The results showed that there were 43 weed species belonging to 19 families in the Z. matrella lawn from 2007 to 2009, in which Gramineae, Compositae, Cyperaceae and Rubiaceae had a comparative advantage. Perennial weeds accounted for the largest proportion of weeds and increased gradually in the three years. Weed communities distributed in higher heterogeneity than in a random model. Dominant weeds varied with season and displayed regularity in the order of 'dicotyledon-monocotyledon-dicotyledon weeds' and 'perennial-annual-perennial weeds'. The spatial heterogeneity of weed community in Z. matrella lawn was higher in summer than in winter. The diversity and evenness of weed community were higher in summer and autumn than in winter and spring. The number of weed species with high heterogeneity in summer was higher than in the other seasons. The spatial heterogeneity and diversity of weed community had no significant change in the three years, while the evenness of weed community had the tendency to decline gradually.

Allelopathic assessment of selected common weeds in Malaysia

Science.gov (United States)

Nurul Ain, M. B.; Nornasuha, Y.; Ismail, B. S.

2016-11-01

A laboratory study was conducted to evaluate the allelopathic potential of eight common weed species in Malaysia, namely, Ageratum conyzoides, Tridax procumbens, Cyperus iria, Fimbristylis miliacea, Eleusine indica, Imperata cylindrica, Lygodium flexuosum and Nephrolepis biserrata of different morphological characteristics (broadleaves, sedges, grasses and ferns). The allelopathic study of these weeds was carried out by testing the leaf litter leachate through the Sandwich method and the volatile compounds of these weeds through the Dish pack method with three replicates for each donor species. The results obtained from both methods were statistically analyzed and the means had converted to percentage growth inhibition to determine the inhibition pattern on the radicle and hypocotyl growth of lettuce seedlings. Among the eight weed species tested, Ageratum conyzoides showed the strongest growth inhibition on lettuce radicle elongation (86%) in the sandwich bioassay compared to the control, followed by Tridax procumbens (71%), which both species being broadleaves weeds. In the dish pack bioassay Lygodium flexuosum (fern) demonstrated maximum inhibition on the growth the radicle and hypocotyl for each different distance from the source well. On the other hand, two weed species exhibited enhanced on the growth radicle and hypocotyl when compared to that of the control in dish pack bioassay. Nephrolepis biserrata and Fimbristylis miliacea were the species that showed the highest growth stimulatory effect. The results presented can be utilized as benchmark information for further research on the elucidation of leachates and volatile chemicals involved in allelopathy in nature. The information can also be helpful in the development of new bioactive chemicals from natural products in weed control strategies.

Pest Control in Corn and Soybeans: Weeds - Insects - Diseases.

Science.gov (United States)

Doersch, R. E.; And Others

This document gives the characteristics and application rates for herbicides used to control annual weeds in corn, annual and perennial broadleaf weeds in corn, quackgrass and yellow nutsedge in corn, and annual weeds in soybeans. It also gives insecticide use information for corn and soybeans. A brief discussion of disease control in corn and…

Comparisons of weed community, soil health and economic performance between wheat-maize and garlic-soybean rotation systems under different weed managements

Directory of Open Access Journals (Sweden)

Mahmud A. Muminov

2018-05-01

Full Text Available This study compared the impacts of different weed managements on weed community, soil health and economic performance between the wheat–maize (WM and garlic–soybean (GS rotations. A total of four treatments (H0T, tillage without herbicide; H0T0, without both herbicide and tillage; HT, both herbicide and tillage; HT0, herbicide without tillage were designed for both rotations. A total of 16 weed species were recorded in the WM rotation, with life forms of 62% for annuals, 12% for annual + perennial and 20% for perennials. While in the GS rotation, there were 17 weed species, with 71% being annuals. When crop rotation changed from WM to GS, the topsoil layer seed bank (0–5 cm decreased by 137%. GS rotation always had higher earthworm densities than that of WM under the same condition. Organic weed control (H0T, H0T0 from both WM and GS added more soil organic matters than the chemical methods (HT and HT0. Economically, up to 69% higher net profit had been achieved in the GS than WM for their organic products. This study provides an ecological basis to guide organic farming practices, especially for weed management in the future.

Weeds in spring cereal fields in Finland - a third survey

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J. SALONEN

2008-12-01

Full Text Available A survey of weeds in spring cereal fields was conducted in 16 regions of southern and central Finland in 1997-1999. Data were collected from conventional and organic farms, both of which applied their normal cropping practices. A total of 690 fields were investigated by counting and weighing the weed species from ten sample quadrats 0.1 m2 in size in late July - early August. Altogether 160 weed species were found, of which 134 were broad-leaved and 26 grass species. The total number of weed species ranged from 41 to 84 between regions. In organically farmed fields, the average species number was 24 and in conventionally farmed fields 16. The most frequent weed species were Viola arvensis 84%, Stellaria media 76% and Galeopsis spp. 70%. Only 18 species exceeded the frequency level of 33%. The average density of weeds was 136 m-2 (median= 91 in sprayed conventional fields, 420 m-2 (374 in unsprayed conventional fields and 469 m-2 (395 in organic fields. The average air-dry above-ground biomass of weeds was 163 kg ha-1 (median=63, 605 kg ha-1 (413 and 678 kg ha-1 (567, respectively. Weed biomass accounted for 3% of the total biomass of the crop stand in sprayed conventional fields and for 17% in organic fields. Elymus repens, the most frequent grass species, produced the highest proportion of weed biomass.

Optical Sensing of Weed Infestations at Harvest.

Science.gov (United States)

Barroso, Judit; McCallum, John; Long, Dan

2017-10-19

Kochia ( Kochia scoparia L.), Russian thistle ( Salsola tragus L.), and prickly lettuce ( Lactuca serriola L.) are economically important weeds infesting dryland wheat ( Triticum aestivum L.) production systems in the western United States. Those weeds produce most of their seeds post-harvest. The objectives of this study were to determine the ability of an optical sensor, installed for on-the-go measurement of grain protein concentration, to detect the presence of green plant matter in flowing grain and assess the potential usefulness of this information for mapping weeds at harvest. Spectra of the grain stream were recorded continuously at a rate of 0.33 Hz during harvest of two spring wheat fields of 1.9 and 5.4 ha. All readings were georeferenced using a Global Positioning System (GPS) receiver with 1 m positional accuracy. Chlorophyll of green plant matter was detectable in the red (638-710 nm) waveband. Maps of the chlorophyll signal from both fields showed an overall agreement of 78.1% with reference maps, one constructed prior to harvest and the other at harvest time, both based on visual evaluations of the three green weed species conducted by experts. Information on weed distributions at harvest may be useful for controlling post-harvest using variable rate technology for herbicide applications.

Weeding method and pre-sowing tillage effects on weed growth and pearl millet yield in a sandy soil of the West African Sahelian zone.

NARCIS (Netherlands)

Klaij, M.C.; Hoogmoed, W.B.

1996-01-01

Weed control for the West African Sahel rainfed crops is done mainly manually, resulting in high labor requirements. Because of the seasonality of rainfed farming, weed control is often late and incomplete, resulting in considerable losses in crop yield. We examined the case of weed control in

Microbiological and chemical transformations of argentatin B.

Science.gov (United States)

Maatooq, Galal T

2003-01-01

Argentatin B is a naturally occurring tetracyclic triterpene isolated from Parthenium argentatum x P. tomentosa. It was microbiologically transformed to 16, 24-epoxycycloartan-3alpha, 25-diol, (isoargentatin D), by Nocardia corallina var. taoka ATCC 31338, Mycobacterium species NRRL B3683 and Septomyxa affinis ATCC 6737. The later microbe also produced 16, 24-epoxycycloartan-3beta, 25-diol (argentatin D) and 1, 2-didehydroargentatin B, (isoargentatin D). Sodium hydroxide converted argentatin B to argentatin D and isoargentatin D. Hydrochloric acid treatment gave cycloartan-25-ol-3, 24-dione. Cerium sulfate/sulfuric acid/aqueous methanol induced scission of the isopropanol moiety and provided an isomeric mixture of 24-methoxy-25-27-trinorargentatin B. Oxidation of this isomeric mixture with pyridinium chlorochromate, selectively, attacked the isomer with the equatorial proton at position-24 to give the corresponding lactone, 24-oxo-25-27-trinorargentatin B. The produced compounds were characterized by spectroscopic methods.

Biotechnological potential of endophytic actinomycetes associated with Asteraceae plants: isolation, biodiversity and bioactivities.

Science.gov (United States)

Tanvir, Rabia; Sajid, Imran; Hasnain, Shahida

2014-04-01

Endophytic actinomycetes from five Asteraceae plants were isolated and evaluated for their bioactivities. From Parthenium hysterophorus, Ageratum conyzoides, Sonchus oleraceus, Sonchus asper and Hieracium canadense, 42, 45, 90, 3, and 2 isolates, respectively, were obtained. Of the isolates, 86 (47.2 %) showed antimicrobial activity. Majority of the isolates were recovered from the roots (n = 127, 69.7 %). The dominant genus was Streptomyces (n = 96, 52.7 %), while Amycolatopsis, Pseudonocardia, Nocardia and Micromonospora were also recovered. Overall, 36 of the 86 isolates were significantly bioactivity while 18 (20.9 %) showed strong bioactivity. In total, 52.1 and 66.6 % showed potent cytotoxicity and antioxidant activities. The LC50 for 15 strains was <20 μg/ml. Compared to the ascorbate standard (EC50 0.34 μg/ml), all isolates gave impressive results with notable EC50 values of 0.65, 0.67, 0.74 and 0.79 μg/ml.

On weed competition and population dynamics : considerations for crop rotations & organic farming

NARCIS (Netherlands)

Mertens, S.K.

2002-01-01

Key words: organic farming, weeds, weed management, weed ecology, weed diversity, matrix population model, elasticity analysis, neighbourhood model, survey, crop row spacing, mechanical hoe, harrow, Polygonum convolvulus ,