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1.
Lepidoptera, with 0.16 million species, is the second largest order of insecta. This order includes silk worms, butterflies, and many agricultural pests. The cotton bollworm, Helicoverpa armigera(Hübner) is one of the pests in Lepidoptera that seriously harms cotton plant and other crops in China and other countries. This pest develops resistance to chemical insecticides rapidly. Bacillus thuringiensis(Bt) transgenic cotton plants are developed to control H. armigera population in the field. However, during the past years, the rapid evolution of Bt toxin resistance is observed in H. armigera in transgenic cotton fields. New approaches for the development of new environmentally friendly insecticides to control H. armigera have become necessary, and the molecular mechanisms underlying the development and physiological processes of this species need to be further understood. Considerable progress in the study of H. armigera development and physiology has been achieved in the last decade. This mini-review summarizes the main findings on the molecular mechanisms of hormonal regulation of the development of H. armigera to present new target genes for developing new approaches to control the pest.  相似文献   

2.
There are several biopesticides based on entomopathogenic fungi available in the market for use against insect pests in greenhouse ecosystems.Although most are compatible for use with predators and parasitoids in greenhouse ecosystems,much more research is needed to determine the intraguild interactions for each combination of host, pathogen, predator, and parasitoid.Our research has demonstrated that, although direct effects on the predators could be demonstrated in laboratory bioassays, different results were found under greenhouse conditions, indicating that results obtained in the laboratory may be a poor predictor of what occurs in the greenhouse.In both cases, additive effects were obtained under greenhouse conditions,demonstrating compatibility. In addition, there is increasing evidence that entomopathogenic fungi have significant potential for dual management of invertebrate pests and plant pathogens.Our studies demonstrated that 3 species of Lecanicillium had significant effects on both aphids and cucumber powdery mildew, Sphaerotheca fuliginea;that the fungus Paecilomyces fumosoroseus was compatible with a mirid predator,Disyphus hesperus,when used concurrently against greenhouse whitefly,Trialeurodes vaporariorum;and that Lecaniciullium longisporum was compatible with a predatory midge,Aphidoletes aphidimyza when used concurrently against green peach aphids.  相似文献   

3.
Advances and Developing Tendency of Water Use Efficiency in Plant Biology   总被引:1,自引:0,他引:1  
Biological water saving is one of the major fields of water saving agriculture in the future and has an enormous potential in agricultural production. In this paper, the necessity and urgency of developing high water use efficiency in plant biology were dissertated firstly, and the research progresses at home and abroad were reviewed as following aspects: mechanisms of drought resistance and high water use efficiency, criterions for identifying and evaluating drought resistance and water use efficiency, genetic improvement for drought resistance and water use efficiency, water saving irrigation technology based on the physiological regulation and control in crop plants. Major problems in the research field at present were put forward, and development tendency of water use efficiency in plant biology in the future were also discussed.  相似文献   

4.
Only two fungus species,Beauveria bassiana and Metarhizium anisopliae,have been given serious attention as possible microbial controls for stored-product pests.Their host ranges are broad, but their potency for the various target insects varies greatly,and some of the most important pests such as the red flour beetle are very tolerant of fungi.Accordingly, strategies are needed to improve the fungal performance.One such strategy is combination with other environmentally benign treatments such as controlled desiccant dusts and controlled atmospheres. Ironically the relatively dryness of stored-product environments favors fungal efficacy.Desiccation stress renders some insects more vulnerable to fungi.The longevity of fungus spores is also best under dry conditions.The prospects of fungi for control of stored-product pests can be improved by taking advantage of these phenomena and judicious selection of use venues and application strategies.  相似文献   

5.
Lepidopteran stem borers are the most damaging pests of maize in Sub-Saharan Africa. Despite the growing importance of maize in the forest zone of Democratic Republic of Congo, no data is available regarding stem borer pest species present and their relative importance. It is thus important to gather information likely to guide future research in this area. This study was undertaken to catalogue stem borer pest species identity and assess their relative infestation levels on maize. Surveys were carried out in wild and cultivated habitats in Kisangani. Five species were collected on maize, i.e., Sesamia calamistis Hampson (1910), Eldana saccharina Walker (1865), Busseola fusca Fuller (1901), Chilo sp. Strand (1913), and Mussidia nigrivenella Ragonot (1888). In the wild habitats, Poenoma serrata Hampson, B. fusca and S. calamistis were collected on Pennisetum purpureum whereas Chilo sp. was collected on Panicum maximum. Our results suggest that P. maximum might affect the population dynamics of Chilo sp. whereas P. purpureum is expected not to influence the population dynamics of other stem borers owing to its scarcity in the interior of the forest.  相似文献   

6.
Recent agricultural biotechnology research and advances in the province are reviewed. Targets and practices for biotechnological development in depth are discussed,with stress on the talent‘s training,new techniques‘ establislunent and its industrialization, starting from the existing level and problems in the field in the province.  相似文献   

7.
Insects are major pests of stored grains. In sub Sahara Africa, stored grain insect pests are mainly Coleoptera or Lepidoptera. In the Logone Valley, area covering the Far North Region of Cameroon and South-West of Chad, to our knowledge, the diversity of insect pests noxious to stored products is not established. These beetles and weevils (Insecta:Coleoptera) during their development depreciate food in storage, were able to destroy a whole stock in a very short period of time if no protection of stored food is made. To achieve the diversity of insect pests, inspections of granaries were done in 209 villages of Logone Valley where insect pests were collected and identified. Secondly, the stored grains were sampled in peasant's granaries of Logone Valley and reared in incubators in the Unit of Entomological Research of the University of Ngaound6r6. After their emergence, insects were removed, collected and identified. Their noxious efficiency on stored grains is done by the calculation of the density of each insect pests per gram of grains. This study indicates that 12 species of harmful insects attack cereals and leguminous grains in the Logone Valley during storage. The Bruchids were the main insect pests of legumes. Callosobruchus maculatus was the main pest of legume and attacking mainly cowpeas (34.92 bruchids/g of seed) and peanuts (20.75 bruchids/g of seed). Seven harmful species destroy the cereals. Sitophilus zeamais is the main pest of maize (15.86 weevils/g of maize) and S. oryzae, for sorghum (36.59 weevils/g of maize). Tribolium castaneum were the main secondary pest. T. castaneum infests both cereals and leguminous. This work summarizes the importance and the diversification of stored grain pests in Logone Valley. Knowing the pest diversity is an important step in the strategy to develop a friendly and ecological control method of these harmful insects.  相似文献   

8.
[Objective] This research aimed to compare arthropod communities in different cruciferous vegetable fields at high mountainous area and provide guidance for pest control.[Method] The main arthropod species in 3 kinds of cruciferous vegetable fields at high mountainous area were investigated,the composition of arthropod community in different vegetable fields were analyzed.[Result] The main arthropod species in cruciferous vegetables fields at high mountainous area were similar,but had different quantity compositions.The richness was the highest in radish field.[Conclusion] Crop species had great influence on biological community;we should focus on the main pests in the process of pest control.  相似文献   

9.
Trichoderma species are currently used as biocontrol agents for crop diseases caused by a number of fungal plant pathogens. However, their biocontrol performance in the field can be unreliable and it is likely that more consistent performance could be achieved through knowledge and manipulation of the genes involved. For example, induction of the genes could be optimised for variable environmental and physiological conditions, superior strains could be selected more effectively and novel st…  相似文献   

10.
Research Status Quo and Future of Low Temperature Wheat Genotypes   总被引:2,自引:1,他引:1  
Low temperature wheat genotypes are a group of wheat with a slightly low canopy (plant) temperature, and the research on their biological characters and utilization in wheat breeding has been done at home and abroad for more than 20 years, and has made great progress. The research contents and advances include the following respects: Wheat genotypes with slightly low canopy temperature have been verified to exist in nature; these wheat genotypes, which present cold temperature, are superior to conventional wheat materials in some important biological characters and particularly prominently in metabolic function and cellular structure; when they suffer stresses such as drought, high temperature and overcast and rainy weather, they still retain their superiority in some of their important biological characters and therefore have a wide range of ecological adaptability; slightly low canopy temperatures of these genotypes are closely correlated with low temperatures of their second heat sources and their vigorous plants; since their low canopy temperatures can be inherited, they can exert favorable influence on the temperatures of their offspring while crossing with other wheat materials, and in particular, the discovery of cold-source wheat as a contributor to low temperature, has further formed good conditions for breeding high and stable quality low temperature wheat varieties with a high and stable yield. Thus, low temperature wheat genotypes are of great research importance and have great prospects.  相似文献   

11.
The study determined the research priorities in Swaziland agricultural sector. Data collection used existing documents on agricultural research prioritizing, Nominal Group Technique and modified Delphi technique, with analysis of data using content categorization and, group and individual ranking of submissions. Findings showed the agricultural priorities from national policies are tied-up with mitigating the effects of HIV and AIDS on food security, reduction of poverty and, sustainable development. The findings also revealed forty-three field crops areas needing research. Seven horticulture areas and eleven livestock sector areas were of high priority. A considerable number of research areas in field crops, horticulture and livestock indicated that the current research system has not adequately addressed research needs, despite efforts made by the private sector, University of Swaziland and Ministry of Agriculture and Cooperatives, for Swaziland to achieve self-sufficiency in food production. Recommendation was that the identified research priorities should be used as basis for directing the limited resources in conducting agricultural research. The participation of all stakeholders would facilitate efficient use of resources and facilitate collaboration amongst research institutions. The University of Swaziland should develop research priorities aligned with national policies and objectives, to facilitate funding for research by both government and donor agencies.  相似文献   

12.
An Image-Based Diagnostic Expert System for Corn Diseases   总被引:1,自引:0,他引:1  
The annual worldwide yield losses due to pests are estimated to be billions of dollars. Integrated pest management (IPM) is one of the most important components of crop production in most agricultural areas of the world, and the effectiveness of crop protection depends on accurate and timely diagnosis of phytosanitary problems. Accurately identifying and treatment depends on the method which used in disease and insect pests diagnosis. Identifying plant diseases is usually difficult and requires a plant pathologist or well-trained technician to accurately describe the case. Moreover, quite a few diseases have similar symptoms making it difficult for non-experts to distinguish disease correctly. Another method of diagnosis depends on comparison of the concerned case with similar ones through one image or more of the symptoms and helps enormously in overcoming difficulties of non-experts. The old adage 'a picture is worth a thousand words' is crucially relevant. Considering the user's capability to deal and interact with the expert system easily and clearly, a webbased diagnostic expert-system shell based on production rules (i.e., IF 〈 effects 〉 THEN 〈 causes 〉) and frames with a color image database was developed and applied to corn disease diagnosis as a case study. The expert-system shell was made on a 32-bit multimedia desktop microcomputer. The knowledge base had frames, production rules and synonym words as the result of interview and arrangement. It was desired that 80% of total frames used visual color image data to explain the meaning of observations and conclusions. Visual color image displays with the phrases of questions and answers from the expert system, enables users to identify any disease, makes the right decision, and chooses the right treatment. This may increase their level of understanding of corn disease diagnosis. The expert system can be applied to diagnosis of other plant pests or diseases by easy changes to the knowledge base.  相似文献   

13.
14.
aquatic product, known as one of the good resources for white meat, has been widely accepted by the consumers due to its high protein, low fat, especially low cholesterol. With the fast development of living standards around the world, the consumer demands for high quality, nutrition, safety and freshness of ifshery food are increasing. Thus, high efifcient preservation technologies for aquatic products become particularly important. Superchilling is one of the controlled-temperature preservation technologies for seafood. Aquatic products can be kept in better quality under superchilling conditions. This review introduced the principle and development of superchilling process, mainly focusing on research progresses and technical dififculties of superchilling. The growth mechanism of ice crystals and the feasibility of application of computational lfuid dynamics in analyzing the temperatures variation and ice crystals during superchilling progress were also discussed, which will provide theoretical foundation for its improvement and application.  相似文献   

15.
RNAi trigged by dsRNA not only facilitates the development of molecular biology, but also initiates a new way for pest control by silence of fatal genes. However, one of the key limitations in pest control is lack of the convenient and efficient method for dsRNA delivery. In this study, different dsRNA delivery methods at their own optimum conditions were evaluated comparatively for their efficiency with Helicoverpa armigera as test animal. It was found that the popular one- time injection of larvae with dsRNA could reduce the pupation rate by 43.0% and enhance larva mortality by 11.7%. One- time ingestion of dsRNA did not result in any significant effect on phenotype. Continuous ingestion of in vitro synthesized dsRNA by refreshing the bait diet every day caused 40.4% decrease in successful pupation and 10.0% increase in larval mortality, which was similar as one-time injection. The most efficient method was found to be the continuous ingestion of the bacteria containing dsRNA expressed, which reduced the rate of pupation by 68.7% and enhanced the larval mortality by 34.1%. Further analysis found that dsRNA was degraded faster in midgut juice than in hemolymph. However, the cell of bacteria could protect dsRNA and delay the degradation in the midgut juice of H. armigera. These results throw light on the application of dsRNA in pest management with proper ways.  相似文献   

16.
稻鸭共育对病虫草害及经济效益的影响(英文)   总被引:2,自引:0,他引:2  
[Objective] Study on the effects of rice-duck mutualism on weeds and insects pests and economic benefits of paddy field.[Method] Comparison of the incidence of weeds,sheath blight and insects pest under rice-duck mutualism,conventional cultivation and control treatment,the yield and economic benefits were analyzed under the 3 treatments.[Result] Average occurrence of weeds in rice-duck mutualism group decreased by 2.33 and 52.08 ind/m2 compared with that in conventional cultivation and control treatment;the control rate of mutualism was up to 75% against rice hopper,but just between 25%-60% against rice leaf roller and Chilo suppressalis.The rates of diseased plant and diseased holl against rice sheath blight were higher and disease indices were lower compared with control group.The yield of mutualism group was identical with conventional cultivation,which was greatly higher than that of control group.The results suggested an higher economic benefits and lower cost benefit ratio for rice-duck mutualism treatment.[Conclusion] Rice-duck mutualism gives birth to a positive effect to control the diseases,insect pests and weeds,as well as to economic benefits,providing basis on extension of rice-duck mutualism system.  相似文献   

17.
Effects of Abiotic Environmental Factors on Soybean Cyst Nematode   总被引:3,自引:0,他引:3  
As a pest, in order to complete its life history and reproduces effectively, soybean cyst nematode (SCN) (Heterodera glycines Ichinche 1952) must adapt to various environments and conditions for long periods of evolution. The nematode is widely dispersed year after year. Controlling this pest requires understanding characters and adaptability of SCN. Effects of abiotic factors, such as temperature, soil humidity, agrotype, pH value, ions, plant exudates, agricultural chemical and cultivation systems on SCN, are reviewed in this paper. The results show that SCN is able to endure various environmental stresses, especially low temperature. Because of its special life history, cyst stage help SCN over winter, resistance of SCN to environmental stress is strong. A few studies have reported the mechanism of SCN environmental adaptability. We emphasized the importance of studying environmental adaptability of SCN, which would benefit the control of SCN by ecological means.  相似文献   

18.
A field survey and policy proposal for Information acquiring ability of Shandong Farmers: Proof from 6 villiages in Jinan and Rizhao Fei Liang Yanhui Xu
Abstract: Informatization is one of the most important trends in agricultural and rural development. So there should be a lot of new farmers who have mordern information sense, master application of information, acquire enough information ability. Based on the field survey for 6 villiages in Jinan and Rizhao, we have found reality and problems in the information acquiring of Shandong farmers. Our research includes information acquiring channels, information demanding sense and content and information screening. Some policy proposals were presented in our research.  相似文献   

19.
In reference to the status quo of research and the application of the agricultural expert system, this paper analyzes problems existing in the current development, and puts forward the idea of research and development for agriculturespecific software. The agent application is discussed, and an agent-based Agricultural Expert System Inspection Tool is constructed. In addition, this paper addresses the outlook in application, potential problems and the development trend of multi-agent-based inspection software for the agricultural expert system.  相似文献   

20.
Research Progress on Nitrogen Use and Plant Growth   总被引:1,自引:0,他引:1  
The application of nitrogen (N) fertilizers in agriculture has been increasing dramatically since 1970s. However, the over-fertilization causes could cause environmental problems, as well as low N use efficiency (NUE). Promoting NUE in plants and minimizing the environmental impacts of N fertilizers had been the focus of the current research. We reviewed the importance of N, N metabolism and plant growth, plant N physiology and the molecular aspect of N metabolism in this paper. The future development of N use and NUE of plants was also discussed.  相似文献   

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