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Vegetable Crops (vegetable + crop)
Selected AbstractsViruses of vegetable crops in AlbaniaEPPO BULLETIN, Issue 3 2005M. Finetti-Sialer Field surveys were carried out in the main vegetable-growing areas of Western and Central Albania to evaluate the sanitary status of open-field and protected cultivations of capsicum, tomato, potato, watermelon, cucumber, courgette, aubergine, lettuce, cabbage, chicory, leek and celery. The following viruses were detected: Alfalfa mosaic alfamovirus (AMV), Cucumber mosaic cucumovirus (CMV), Potato Y potyvirus (PVY), Tomato spotted wilt tospovirus (TSWV) and Watermelon mosaic potyvirus 2 (WMV-2). The virus found most frequently was CMV and all the isolates identified were of subgroup IA. AMV was also detected in several areas and all isolates were of subgroup II, suggesting a French origin. Finally, at the time of this survey, TSWV infections appeared to be moderately relevant and absent in protected crops. This is the first documented record of AMV, CMV, PVY, TSWV and WMV-2 in Albania. No infection by Tomato yellow leaf curl begomovirus (TYLCV) or Zucchini yellow mosaic potyvirus (ZYMV) was detected during this survey. [source] Tospoviruses infecting vegetable crops in IsraelEPPO BULLETIN, Issue 2 2000A. Gera Symptoms of vein clearing, stem necrosis, curling, necrotic spots and rings on the leaves associated with infection by tomato spotted wilt tospovirus (TSWV) were documented among vegetable crops growing in commercial glasshouses and open fields in Israel. Plants exhibiting symptoms were collected, from 1994-01 to 1998-12. Among cultivated vegetable crops analysed for TSWV by ELISA, the following plants were found to be infected: tomato, capsicum, aubergine, lettuce, cabbage and cucumber. These incidences of the virus were all correlated with the occurrence in high population of Frankliniella occidentalis. Transmission of the virus from infected Datura stramonium to Petunia leaf discs, by F. occidentalis, was up to 26%. TSWV antigens were readily detected by ELISA in seeds harvested from naturally infected vegetable crops. However, we failed to show virus transmission to the progeny plants. Iris yellow spot tospovirus (IYSV) was detected in onion. High incidence of the disease was associated with large populations of Thrips tabaci. [source] Qualitative and quantitative responses of Diabroticina (Coleoptera: Chrysomelidae) to cucurbit extracts linked to species, sex, weather and deployment methodJOURNAL OF APPLIED ENTOMOLOGY, Issue 3 2008G. Cabrera Walsh Abstract Toxic baits and traps for Diabroticina, based on bitter cucurbit extracts, have been utilized for a number of years with inconsistent results. Four species of bitter Cucurbitaceae were compared in the field for their attractancy to species of Diabroticina in Argentina and the United States. The comparisons were made with polyester fabrics treated with known volumes of different cucurbit extracts, against a standard cucurbit extract of bitter Hawkesbury watermelon (Citrullus lanatus (Thunberg) Matsumura and Nakai). The factors evaluated were: the attractancy of the different extracts in terms of beetle numbers, species and sex of the Diabroticina caught; influence of different fabrics on such attraction; and influence of several weather variables on the catches. The most attractive species was Cayaponia bonariensis (Miller) Martinez Crovetto, however, practical considerations indicated that Cucumis myriocarpus Naudin and Hawkesbury watermelon may be better choices from the commercial perspective. No single weather factor could explain the catches throughout the sample range, but different temperature and barometric pressure ranges provided some predictive value. Although the susceptibility to weather conditions and a strong male dominance in the catches raise the question of the usefulness of cucurbitacins as the main component in toxic baits or traps, these drawbacks may prove to be less important in widespread bait applications and Diabroticina management in vegetable crops. [source] Land application of treated sewage sludge: quantifying pathogen risks from consumption of cropsJOURNAL OF APPLIED MICROBIOLOGY, Issue 2 2005P. Gale Abstract Aims:, To predict the number of humans in the UK infected through consumption of root crops grown on agricultural land to which treated sewage sludge has been applied in accordance with the current regulations and guidance (Safe Sludge Matrix). Methods and Results:, Quantitative risk assessments based on the source, pathway, receptor approach are developed for seven pathogens, namely salmonellas, Listeria monocytogenes, campylobacters, Escherichia coli O157, Cryptosporidium parvum, Giardia, and enteroviruses. Using laboratory data for pathogen destruction by mesophilic anaerobic digestion, and not extrapolating experimental data for pathogen decay in soil to the full 30-month harvest interval specified by the Matrix, predicts 50 Giardia infections per year, but less than one infection per year for the other six pathogens. Assuming linear decay in the soil, a 12-month harvest interval eliminates the risks from all seven pathogens; the highest predicted being one infection of C. parvum in the UK every 45 years. Computer simulations show that a protective effect from binding of pathogens to particulate matter could potentially exaggerate the observed rate of decay in experimental systems. Conclusions:, The results confirm, assuming pathogens behave according to our current understanding, that the risks to humans from consumption of vegetable crops are remote. Furthermore the harvest intervals stipulated by the Safe Sludge Matrix compensate for potential lapses in the operational efficiency of sludge treatment. Significance and Impact of the Study:, The models demonstrate the huge potential impact of decay in the soil over the 12/30-month intervals specified by the Matrix, although lack of knowledge on the exact nature of soil decay processes is a source of uncertainty. The models enable the sensitivity of the predicted risks to changes in the operational efficiency of sewage sludge treatment to be assessed. [source] Agricultural diversification and integrated pest management in BangladeshAGRICULTURAL ECONOMICS, Issue 3 2004Chowdhury Mahmoud IPM; Bangladesh; Vegetable production; Off-farm employment Abstract We study factors associated with a shift toward diversified, high-valued vegetable crops and the incentives associated with the use of IPM methods for vegetable producers in Bangladesh. The primary objective is to measure how IPM technologies affect the crop and technology choices of low-income rice farmers. A three-season household optimisation model is used to study crop and technology choice under price and yield uncertainty. The model is parameterised using data from vegetable farms and experimental IPM trials conducted in Bangladesh. Simulation results show that access to IPM technology and IPM availability combined with access to credit increase household welfare and lead to higher rates of vegetable adoption. Off-farm employment opportunities work against vegetable cultivation and IPM use by risk-averse farmers. Implications for policy and extension efforts are highlighted. [source] Multi-national corporations and agricultural development: a study of contract farming in the Indian PunjabJOURNAL OF INTERNATIONAL DEVELOPMENT, Issue 2 2002Sukhpal Singh This paper examines the rationale, practice and implications of contract farming under the MNCs in vegetable crops in the Indian Punjab from the new institutional economics perspective. It is found that the MNCs deal with relatively large producers, their contracts are biased against the farmer, and the contract crops perpetuate many of the existing problems of the farming sector like high chemical input intensity, unstable future incomes, and social differentiation, though contracting has led to higher farm incomes and labour employment, especially for women. There is an inherent contradiction in the objectives of the contracting parties and that of the local economy and suitable institutions and organisations are not present in the state. Copyright © 2002 John Wiley & Sons, Ltd. [source] Balancing fertility management and economics in organic field vegetable rotationsJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 15 2007Ulrich Schmutz Abstract BACKGROUND: Organic field-scale vegetables are among the most profitable enterprises in organic farming systems. They are also some of the most nutrient-demanding crops, and many organic arable systems with field-scale vegetables are stockless. Without livestock manure inputs, nutrient supply depends on fertility-building crops, which generate only costs and no income. Different strategies of fertility management were compared on a central England research farm. Fertility management treatments consisted of different lengths of fertility building with green waste compost additions. Outputs and inputs in terms of nutrients and economics were monitored for 31 rotations during 1996,2002. RESULTS: N, P and K rotational nutrient balances, as well as C inputs, showed a negative relationship with rotational gross margins. Variable and allocated fixed costs of fertility building were low, between 2 and 5% of variable costs (£0.5,2 ha,1 for 1 kg N ha,1 supplied to the rotation). The intensity of vegetable cropping in these rotations was moderate (25,40% vegetable crops in the rotation) and balancing of fertility management and economics was possible at this intensity without livestock manure or other permitted fertiliser additions. CONCLUSION: Completely stockless systems (in analogy may be called vegan) are possible in organic vegetable production without compromising on fertility or economics. However, for a higher vegetable-cropping intensity (up to 90%) a more sophisticated mix of short-term fertility-building and N-trapping crops will be needed and such rotations may require further external addition of green waste or livestock manure. Copyright © 2007 Society of Chemical Industry [source] Microsatellites reveal a lack of structure in Australian populations of the diamondback moth, Plutella xylostella (L.)MOLECULAR ECOLOGY, Issue 1 2006N. M. ENDERSBY Abstract The diamondback moth, Plutella xylostella, is renowned for developing resistance to insecticides and causing significant economic damage to Brassica vegetable crops throughout the world. Yet despite its economic importance, little is known about the population structure and movement patterns of this pest both at local and regional scales. In Australia, the movement patterns and insecticide resistance status of P. xylostella infesting canola, vegetables, forage brassicas and weeds have fundamental implications for the management of this pest. Here we use six polymorphic microsatellite loci to investigate population structure and gene flow in Australian populations of P. xylostella. Samples of P. xylostella from New Zealand, Malaysia, Indonesia and Kenya were also scored at these loci. We found no evidence of population structure within Australia, with most populations having low inbreeding coefficients and in Hardy,Weinberg equilibrium. In addition, a sample from the North Island of New Zealand was indistinguishable from the Australian samples. However, large genetic differences were found between the Australia/New Zealand samples and samples from Kenya, Malaysia and Indonesia. There was no relationship between genetic distance and geographic distance among Australian and New Zealand samples. Two of the loci were found to have null alleles, the frequency of which was increased in the populations outside the Australia/New Zealand region. We discuss these results with reference to insecticide resistance management strategies for P. xylostella in Australia. [source] Floral attractants for the female soybean looper, Thysanoplusia orichalcea (Lepidoptera: Noctuidae)PEST MANAGEMENT SCIENCE (FORMERLY: PESTICIDE SCIENCE), Issue 12 2008Lloyd D Stringer Abstract BACKGROUND: The soybean looper, Thysanoplusia orichalcea (F.), is a polyphagous insect pest of vegetable crops. Indonesian in origin, it has spread to Europe, India, Africa, Australia and New Zealand. The identification of an attractant for female T. orichalcea could enable the development of alternative pest management strategies to those provided by insecticides or sex pheromones, which are often only attractive to males. RESULTS: Traps baited with synthetic lures derived from Canada thistle, Cirsium arvense (L.) Scop., floral volatiles attracted female T. orichalcea. Phenylacetaldehyde, a floral compound attractive to many Lepidoptera and present in C. arvense, was tested alone as an attractant for the soybean looper and caught significantly more female than male T. orichalcea. Trap catch was greatest when phenylacetaldehyde was combined with five prevalent volatiles present in C. arvense headspace collections: 2-phenylethyl alcohol, methyl salicylate, dimethyl salicylate, benzaldehyde and benzyl alcohol. Twice as many female moths as males were collected. CONCLUSION: Successful trapping of female T. orichalcea in either a lure-and-kill or a mass trapping system may offer an effective way to manage its population size. Copyright © 2008 Society of Chemical Industry [source] Insecticide toxicity and synergism by enzyme inhibitors in 18 species of pest insect and natural enemies in crucifer vegetable cropsPEST MANAGEMENT SCIENCE (FORMERLY: PESTICIDE SCIENCE), Issue 5 2007Gang Wu Abstract The toxicities of three enzyme inhibitors and their synergistic effects on four insecticides were studied by using the dry film method on field populations of 18 species of insects collected in Jianxin and Shanjie, China, from 2003 to 2005. Meanwhile, the inhibitory effects of these enzyme inhibitors on the activities of acetylcholinesterases (AChE), carboxyesterases (CarE) and glutathione- S -transferases (GST), in vivo, were also studied. In general, triphenyl phosphate (TPP) and diethyl maleate (DEM) showed low toxicities to six herbivorous pest insects, four ladybirds and eight parasitoids. Piperonyl butoxide (PB) exhibited low toxicities to the herbivorous pest insects and ladybirds, but high toxicities to the eight parasitoids. The tolerance to the insecticides in 11 pest insects and natural enemies was mainly associated with the tolerance to PB. PB showed the highest synergism on methamidophos, fenvalerate, fipronil and avermectin in nine species of pest insects and natural enemies. In general, TPP and DEM showed significant synergisms to these four insecticides in four parasitoid species. However, in contrast to their effects on the parasitoids, the synergistic effects of TPP and DEM on the four insecticides by TPP and DEM against four pest insects and one ladybird varied depending on the insect species and enzyme inhibitor. Activity of AChE, CarE or GST could be strongly inhibited, in vivo, by PB, TPP or DEM, depending on the insect species and enzyme inhibitors. From the results obtained in this study, mixed-function oxidase (MFO) was thought to play the most critical role in insect tolerances to the tested insecticides in the field. Low competition existed in the evolution of insecticide resistance in the field populations of parasitoids, as compared with herbivorous pest insects and ladybirds. Possible causes of the high synergistic effects of PB on the four classes of insecticides, based on multiattack on the activity of CarE, GST or AChE in the insect species, are also discussed. Copyright © 2007 Society of Chemical Industry [source] Evaluation of existing and new insecticides including spirotetramat and pyridalyl to control Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae) on peppers in QueenslandAUSTRALIAN JOURNAL OF ENTOMOLOGY, Issue 2 2010Iain R Kay Abstract Insecticides are used by growers to control Frankliniella occidentalis (western flower thrips) in Australian vegetable crops. However, limited information was available on the efficacy of some insecticides used against F. occidentalis and data on new insecticides that could be included in a resistance management program were required. The efficacy of 16 insecticides in controlling F. occidentalis was tested in four small plot trials in chillies and capsicums. Spinosad, fipronil and methamidophos were effective against adults and larvae. Spirotetramat had no efficacy against adults but was very effective against larvae. Pyridalyl was moderately effective against larvae. Methidathion showed limited effectiveness. Abamectin, amorphous silica, bifenthrin, chlorpyrifos, dimethoate, emamectin benzoate, endosulfan, imidacloprid, methomyl and insecticidal soap were not effective. Laboratory bioassays on F. occidentalis collected from the field trials showed resistance to bifenthrin but not to the other insecticides tested. The trials demonstrated that some insecticides permitted for use against F. occidentalis are not effective and identified a number of insecticides, including the new ones spirotetramat and pyridalyl, that are effective and that could be used to manage the pest within a resistance management program. [source] | |||||||||||||