994 resultados para Insect Control.


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Pós-graduação em Agronomia (Proteção de Plantas) - FCA

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The use of plants compounds for the control of insects has increased worldwide. This occurs because the vegetal insecticides contains biodegradable compounds, nontoxic products and potentially suitable for use in pest control. Plants of the family Annonaceae are standing out as biopesticides because they are bioactive naturally in addition to presenting cytotoxic activity, antitumor, vermifuge, antimicrobial, immunosuppressive, anti-emetic, inhibiting appetite, antimalarial and also insecticide. The insecticidal activity of Annonaceae is due to the presence of acetogenins, substances that act on mitochondria inhibiting the NADH -ubiquinone oxidoreductase, causing the death of insects. In this review we report the use of Annonaceae in insect control, showing that so far, only 42 species of Annonaceae have information insecticidal activity against just over 60 species of insect pests. This information shows that much research is still needed, especially to get to know the insecticidal activity of other Annonaceae species, in addition to its effects on insect pests not yet studied. So we will have as an alternative to sustainable development, new vegetal insecticides such as those obtained from different Annonaceae species, which can act as an additional tool to balance the excesses of agriculture chemical or conventional.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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This report covers the investigations, expenditures, and publications of the Nebraska Agricultural Experiment Station for the fiscal year June 30, 1931. During the year 68 projects have been under investigation at the main station. These have covered a wide range of subjects. At the various substations the work is planned to meet the needs of the different regions. The funds for carrying on the work of the stations are derived from federal and state sources. The work is carried on in definite projects according to the supporting fund. Satisfactory progress was made on the research program. During the year eight projects were completed and seven new ones added. The selection of new projects is on the basis of most urgent need, together with the ability of the Experiment Station to carry the project. The financial depression in which agriculture still finds itself has increased rather than decreased the demand upon the Experiment Station and the College for new and definite information. This demand has been taken care of insofar as possible. During the year covered by this report eleven bulletins, nine research bulletins, and one circular have been published by the Experiment Station. In addition 22 technical papers have been prepared by members of the staff and printed in various technical and professional journals.

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Organic farming means a holistic application of agricultural land-use, hence, this study aimed to assess ecological and socio-economic aspects that show benefits of the strategy and achievements of organic farming in comparison to conventional farming in Darjeeling District, State of West Bengal, India and Kanagawa Prefecture/Kanto in Central Japan. The objective of this study has been empirically analysed on aspects of crop diversity, yield, income and sales prices in the two study regions, where 50 households each, i.e. in total 100 households were interviewed at farm-level. Therefore, the small sample size does not necessarily reflect the broad-scale of the use and benefit of organic farming in both regions. The problems faced in mountainous regions in terms of agriculture and livelihoods for small-scale farmers, which are most affected and dependant on their immediate environment, such as low yields, income and illegal felling leading to soil erosion and landslides, are analyzed. Furthermore, factors such as climate, soils, vegetation and relief equally play an important role for these farmers, in terms of land-use. To supplement and improve the income of farmers, local NGOs have introduced organic farming and high value organic cash crops such as ginger, tea, orange and cardamom and small income generating means (floriculture, apiary etc.). For non-certified and certified organic products the volume is given for India, while for Japan only certified organic production figures are given, as there are several definitions for organic in Japan. Hence, prior to the implementation of organic laws and standards, even reduced chemical input was sold as non-certified organic. Furthermore, the distribution and certification system of both countries are explained in detail, including interviews with distribution companies and cooperatives. Supportive observations from Kanagawa Prefecture and the Kanto region are helpful and practical suggestions for organic farmers in Darjeeling District. Most of these are simple and applicable soil management measures, natural insect repelling applications and describe the direct marketing system practiced in Japan. The former two include compost, intercropping, Effective Microorganisms (EM), clover, rice husk charcoal and wood vinegar. More supportive observations have been made at organic and biodynamic tea estates in Darjeeling District, which use citronella, neem, marigold, leguminous and soil binding plants for soil management and natural insect control. Due to the close ties between farmers and consumers in Japan, certification is often neither necessary nor wanted by the producers. They have built a confidence relationship with their customers; thus, such measures are simply not required. Another option is group certification, instead of the expensive individual certification. The former aims at lower costs for farmers who have formed a cooperative or a farmers' group. Consumer awareness for organic goods is another crucial aspect to help improve the situation of organic farmers. Awareness is slightly more advanced in Kanto than in Darjeeling District, as it is improved due to the close (sales) ties between farmers and consumers in Kanto. Interviews conducted with several such cooperatives and companies underline the positive system of TEIKEI. The introduction of organic farming in the study regions has shown positive effects for those involved, even though it still in its beginning stages in Darjeeling District. This study was only partly able to assess the benefits of organic agriculture at its present level for Darjeeling District, while more positively for the organic farmers of Kanto. The organic farming practice needs further improvement, encouragement and monitoring for the Darjeeling District farmers by locals, consumers, NGOs and politicians. The supportive observations from Kanagawa Prefecture and the Kanto region are a small step in this direction, showing how, simple soil improvements and thus, yield and income increases, as well as direct sales options can enhance the livelihood of organic farmers without destroying their environment and natural resources.

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The prevalence of Ventilated Improved Pit (VIP) latrines in Ghana suggests that the design must have a high user acceptance. The two key factors attributed to user acceptance of a VIP latrine over an alternative latrine design, such as the basic pit latrine, are its ability to remove foul odors and maintain low fly populations; both of which are a direct result of an adequate ventilation flow rate. Adequate ventilation for odorless conditions in a VIP latrine has been defined by the United Nations Development Program (UNDP) and the World Bank, as an air flow rate equivalent to 6 air changes per hour (6 ACH) of the superstructure’s air volume. Additionally, the UNDP determined that the three primary factors that affect ventilation are: 1) wind passing over the mouth of the vent pipe, 2) wind passing into the superstructure, and 3) solar radiation on to the vent pipe. Previous studies also indicate that vent pipes with larger diameters increase flow rates, and the application of carbonaceous materials to the pit sludge reduces odor and insect prevalence. Furthermore, proper design and construction is critical for the correct functioning of VIP latrines. Under-designing could cause problems with odor and insect control; over-designing would increase costs unnecessarily, thereby making it potentially unaffordable for benefactors to independently construct, repair or replace a VIP latrine. The present study evaluated the design of VIP latrines used by rural communities in the Upper West Region of Ghana with the focus of assessing adequate ventilation for odor removal and insect control. Thirty VIP latrines from six communities in the Upper West Region of Ghana were sampled. Each VIP latrine’s ventilation flow rate and micro-environment was measured using a hot-wire anemometer probe and portable weather station for a minimum of four hours. To capture any temporal or seasonal variations in ventilation, ten of the latrines were sampled monthly over the course of three months for a minimum of 12 hours. A latrine usage survey and a cost analysis were also conducted to further assess the VIP latrine as an appropriated technology for sustainable development in the Upper West Region. It was found that the average air flow rate over the entire sample set was 11.3 m3/hr. The minimum and maximum air flow rates were 0.0 m3/hr and 48.0 m3/hr respectively. Only 1 of the 30 VIP latrines (3%) was found to have an air flow rate greater than the UNDP-defined odorless condition of 6 ACH. Furthermore, 19 VIP latrines (63%) were found to have an average air flow rate of less than half the flow rate required to achieve 6 ACH. The dominant factors affecting ventilation flow rate were wind passing over the mouth of the vent pipe and air buoyancy forces, which were the effect of differences in temperature between the substructure and the ambient environment. Of 76 usable VIP latrines found in one community, 68.4% were in actual use. The cost of a VIP latrine was found to be equivalent to approximately 12% of the mean annual household income for Upper West Region inhabitants.

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Pest management practices that rely on pesticides are growing increasingly less effective and environmentally inappropriate in many cases and the search of alternatives is under focus nowadays. Exclusion of pests from the crop by means of pesticide-treated screens can be an eco-friendly method to protect crops, especially if pests are vectors of important diseases. The mesh size of nets is crucial to determine if insects can eventually cross the barrier or exclude them because there is a great variation in insect size depending on the species. Long-lasting insecticide-treated (LLITN) nets, factory pre-treated, have been used since years to fight against mosquitoes vector of malaria and are able to retain their biological efficacy under field for 3 years. In agriculture, treated nets with different insecticides have shown efficacy in controlling some insects and mites, so they seem to be a good tool in helping to solve some pest problems. However, treated nets must be carefully evaluated because can diminish air flow, increase temperature and humidity and decrease light transmission, which may affect plant growth, pests and natural enemies. As biological control is considered a key factor in IPM nowadays, the potential negative effects of treated nets on natural enemies need to be studied carefully. In this work, the effects of a bifentrhin-treated net (3 g/Kg) (supplied by the company Intelligent Insect Control, IIC) on natural enemies of aphids were tested on a cucumber crop in Central Spain in autumn 2011. The crop was sown in 8x6.5 m tunnels divided in 2 sealed compartments with control or treated nets, which were simple yellow netting with 25 mesh (10 x 10 threads/cm2; 1 x 1 mm hole size). Pieces of 2 m high of the treated-net were placed along the lateral sides of one of the two tunnel compartments in each of the 3 available tunnels (replicates); the rest was covered by a commercial untreated net of a similar mesh. The pest, Aphis gossypii Glover (Aphidae), the parasitoid Aphidius colemani (Haliday) (Braconidae) and the predator Adalia bipunctata L. (Coccinellidae) were artificially introduced in the crop. Weekly sampling was done determining the presence or absence of the pest and the natural enemies (NE) in the 42 plants/compartment as well as the number of insects in 11 marked plants. Environmental conditions (temperature, relative humidity, UV and PAR radiation) were recorded. Results show that when aphids were artificially released inside the tunnels, neither its number/plant nor their distribution was affected by the treated net. A lack of negative effect of the insecticide-treated net on natural enemies was also observed. Adalia bipunctata did not establish in the crop and only a short term control of aphids was observed one week after release. On the other hand, A. colemani did establish in the crop and a more long-term effect on the numbers of aphids/plant was detected irrespective of the type of net. KEY WORDS: bifenthrin-treated net, Adalia bipunctata, Aphidius colemani, Aphis gossypii, semi-field

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"Interim report no. 0-100 (NRC Insect control committee Report no. 100). A report to the Committee on medical research on work done under a transfer of funds, recommended by this committee, from the Office of scientific research and development to the Bureau of entomology and plant quarantine."--Foot-note, p. 1.

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The juvenile hormones (JHs) are sesquiterpenoid compounds that play a central role in insect reproduction, development and behavior. They are synthesized and secreted by a pair of small endocrine glands, the corpora allata (CA), which are intimately connected to the brain. The enzymes involved in the biosynthesis of JH are attractive targets for the control of mosquito populations. This dissertation is a comprehensive functional study of five Aedes aegypti CA enzymes, HMG-CoA synthase (AaHMGS), mevalonate kinase (AaMK), phosphomevalonate kinase (AaPMK), farnesyl diphosphate synthase (AaFPPS) and farnesyl pyrophosphate phosphatase (AaFPPase). The enzyme AaHMGS catalyzes the condensation of acetoacetyl-CoA and acetyl-CoA to produce HMG-CoA. The enzyme does not require any co-factor, although its activity is enhanced by addition of Mg2+. The enzyme AaMK is a class I mevalonate kinase that catalyzes the ATP-dependent phosphorylation of mevalonic acid to form mevalonate 5-phosphate. Activity of AaMK is inhibited by isoprenoids. The enzyme AaPMK catalyzes the cation-dependent reversible reaction of phosphomevalonate and ATP to form diphosphate mevalonate and ADP. The enzyme AaFPPS catalyzes the condensation of isopentenyl diphosphate (IPP) and dimethylallyl pyrophosphate (DMAPP) to form geranyl diphosphate (GPP) and farnesyl pyrophosphate (FPP). The enzyme AaFPPS shows an unusual product regulation mechanism, with chain length final product of 10 or 15 C depending on the metal cofactor present. The enzymes AaFPPase-1 and AaFPPase-2 efficiently hydrolyze FPP into farnesol, although RNAi experiments demonstrate that only AaFPPase-1 is involved in the catalysis of FPP into FOL in the CA of A. aegypti. This dissertation also explored the inhibition of the activity of some of the JH biosynthesis enzymes as tools for insect control. We described the effect of N-acetyl-S-geranylgeranyl-L-cysteine as a potent inhibitor of AaFPPase 1 and AaFPPase-2. In addition, inhibitors of AaMK and AaHMGS were also investigated using purified recombinant proteins. The present study provides an important contribution to the characterization of recombinant proteins, the analysis of enzyme kinetics and inhibition constants, as well as the understanding of the importance of these five enzymes in the control of JH biosynthesis rates.

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Age is a critical determinant of the ability of most arthropod vectors to transmit a range of human pathogens. This is due to the fact that most pathogens require a period of extrinsic incubation in the arthropod host before pathogen transmission can occur. This developmental period for the pathogen often comprises a significant proportion of the expected lifespan of the vector. As such, only a small proportion of the population that is oldest contributes to pathogen transmission. Given this, strategies that target vector age would be expected to obtain the most significant reductions in the capacity of a vector population to transmit disease. The recent identification of biological agents that shorten vector lifespan, such as Wolbachia, entomopathogenic fungi and densoviruses, offer new tools for the control of vector-borne diseases. Evaluation of the efficacy of these strategies under field conditions will be possible due to recent advances in insect age-grading techniques. Implementation of all of these strategies will require extensive field evaluation and consideration of the selective pressures that reductions in vector longevity may induce on both vector and pathogen.