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11.
Grain legumes play an important role in community livelihood and in the national economy in Kenya. Unfortunately, in many African countries, production doesn't satisfy the demand in grains due to various constrains. Understanding farmers practices and behavior in the management of grain legume pests is a crucial step in the development of sustainable management strategies. A total of 216 farmers were surveyed in eight districts of eastern Kenya to evaluate farmers' knowledge and perceptions of grain legume pests; to examine current pest management practices, and to identify other production constraints. Grain legumes are grown by a wide age-group of farmers, with both genders equally represented. Chemical control remains the main pest management strategy, and, to ensure pesticide effectiveness, farmers also use increased application rates, chemical alternation, frequent application and mixtures of chemicals. While farmers used other control measures, they showed only limited interest in biological control. The majority of the farmers had experience in grain legume farming and were able to identify the major pests, which were the legume flower thrips Megalurothrips sjostedti Trybom, the cowpea aphid Aphis craccivora Koch and the legume pod borer Maruca vitrata Fabricius. Our survey revealed that education and proximity to extension services contributed significantly to farmers' knowledge of grain legume pests, suggesting the need to provide continuous training and capacity building on integrated pest management in grain legume farming. The study also suggests integration of other pest management strategies such as the use of early maturing varieties, biopesticides and biofertilizer to reduce the use of chemical for sustainable pest management. 相似文献
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甲胺磷(methamidophos)具有内吸、触杀和胃毒杀作用,防治抗性蚜、蟥和水稻叶蝉、悦虱等药效较好,但残留期较长,有时会影响作物的品质。通过对贵阳地区水稻中甲胺磷农药残留分析,得到贵阳地区的大米中甲胺磷未检出。样品以丙酮提取,经过盐析、再经二氯甲烷萃取后进行气相色谱分析(最低检测浓度为0.03μg/g),本方法的结果符合农药残留分析的要求,因此说明贵阳地区的大米中甲胺磷没有超标,为贵阳地区绿色食品的开发提供理论依据。 相似文献
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为了比较和鉴定近年来引进的新型农药的药效,为我区大田推广提供可靠的科学依据,特进行新型农药的药效对比试验,试验证明,麦田防除阉叶草试验中:2.4-D丁酯、麦草灵这二种农药的表现较为突出;油菜防除蚜虫试验中“乐斯本”效果最邓;高盖”对于双子叶作物田防治单子叶杂草具有十分良好的作用。 相似文献
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QSAR及其在农药设计中的应用和进展 总被引:11,自引:1,他引:11
在介绍定量结构 -活性关系 (QSAR)的基本原理后 ,重点评述了 QSAR各种方法的主要原理、优缺点及其在农药设计中的研究应用进展 ,包括取代基多参数法 (Hansch法 )、Free- Wilson法、分子轨道法 (MO)、距离比较法 (DISCO)、比较分子力场分析法 (Co MFA)、分子模拟法 (MS)、分子对接法 (MD)、人工神经网络法 (ANN)以及 Leapfrog法等。 相似文献
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近几年来随着音乐课程改革的不断深化及国内外教学手段的不断发展,我国的多媒体辅助教学已被广泛运用基础教育的各门学科中。而在音乐教育中,多媒体辅助教学不仅能给学生快速地提供丰富多彩的集图、文、声与一体的教学信息,而且给学生提供更加自由、更加生动与多样化的音乐课堂。但是,音乐教师在对于多媒体技术的运用时,也应当注意它的正确性与合理性,这样才会促进多媒体辅助音乐教学课堂更加多姿多彩,更加完美。本文对此进行了探讨。 相似文献
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Rust control and ethylenebisdithiocarbamate (EBDC) residues in green beans ( Phaseolus vulgaris L. 'Morgan') were evaluated in two seasons of 1993 in Dschang, Cameroon. Four weekly applications of mancozeb (2.8 kg ha- 1), sulphur (2.24 kg ha- 1), or mancozeb+sulphur (1.4+1.12 kg ha- 1) were initiated from initial rust symptoms. In both seasons, treatments with mancozeb alone resulted in a low area under pustule count progress curve (AUPPC) and a significant increase in leaf area index, and pod and green fodder yields. Pod yields were negatively correlated with AUPPC. Pod yield loss was estimated at 61% and 32% in the early and late seasons, respectively, while losses in green fodder yields were 57% and 24% respectively. EBDC residue levels decreased significantly with a delay in pod harvestand when pods were washed in running tap water. Residue levels were high in the late season, possibly due to low rainfall. Pods exposed to the combined fungicidal treatments accumulated higher levels of residues than those sprayed with mancozeb alone, suggesting a potential risk of EBDC accumulation on pods when EBDCs are mixed with sulphur. 相似文献