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Janet Hemingway R. Patricia Penilla Americo D. Rodriguez Bronwen M. James William Edge Hilary Rogers Mario H. Rodriguez 《Pest management science》1997,51(3):375-382
A resistance management programme comparing rotations, mosaics and single use of insecticides for residual house-spraying against the insect vectors of malaria is being carried out in Southern Mexico. The area was chosen because of its prior history of insecticide use, relatively sedentary vector, and physical features of the area which limit inward migration of insects to the study area. A high level of resistance to DDT and low levels of organophosphorus (OP), carbamate and pyrethroid resistance were detected by WHO discriminating-dose assays in field populations of Anopheles albimanus in the pre-spray period in the region where this resistance management project is being undertaken. After the first year of spraying, resistance, as measured by a discriminating-dose assay, was still at a high level for DDT and had risen for all the other insecticides. Biochemical assays showed that DDT resistance was primarily caused by elevated levels of glutathione S-transferase (GST) activity leading to increased rates of metabolism of DDT to DDE. The numbers of individuals with elevated GST and DDT resistance were well correlated, suggesting that this is the only major DDT resistance mechanism in this population. The carbamate resistance in this population was conferred by an altered acetylcholinesterase (AChE) mechanism. The level of resistance in bioassays correlated well with the frequency of individuals homozygous for the altered AChE allele. This suggests that the level of resistance conferred by this mechanism in its heterozygous state is below the level of detection of the bioassay. The low levels of OP and pyrethroid resistance could be conferred by either the elevated esterase or monooxygenase enzymes. The esterases, however, are elevated only with p-nitrophenyl acetate (PNPA), and are unlikely to be causing broad-spectrum OP resistance. The altered AChE mechanism may also be contributing to the OP but not the pyrethroid resistance. There were significant differences in some resistance gene frequencies for insects obtained by different indoor and outdoor trapping methods. To determine whether the different sampling methods were effectively sampling the same interbreeding population, RAPD analysis of insects obtained by different collection methods in different villages was undertaken. There was no observed variability in the RAPD patterns for the different mosquito samples with a number of primers. ©1997 SCI 相似文献
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以带有不同白粉病病斑面积比例的腰果种子为材料,研究不同白粉病侵染程度的腰果种子发芽率及其幼苗生长的差异.结果表明,白粉病病斑面积比例为100％的腰果种子,其发芽率及其幼苗叶片数、直径、株高、叶长、叶宽总体上均显著低于病斑面积比例小于100％的处理;病斑面积比例在50％～99％之间的腰果种子与病斑面积比例小于50％的种子相比,前者幼苗直径显著低于后者,发芽率及其幼苗株高、叶长、叶宽之间的差异未达显著水平.建议在选择腰果种子用于育苗时,选择白粉病病斑面积比例低于50％的种子,以确保种子发芽率及幼苗质量.受白粉病侵染的腰果种子发芽率与其幼苗生长指标之间显著正相关,发芽率高的种子,其幼苗生长相对较好. 相似文献
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运用聚集度指标法、Iwao法和Taylor法进行测定检验,研究了长结织叶蚁Oecophylla longinoda蚁巢在腰果树上的空间分布型和垂直分布。多项聚集度指标表明长结织叶蚁蚁巢在腰果树上属聚集分布,但负二项分布K值大于8,说明长结织叶蚁蚁巢空间分布近似随机。从地表至树顶4～5 m树高范围和40%～50%树高比例范围长结织叶蚁蚁巢分布比率均最高,分别为30.49%和26.48%,显著高于其它树高范围或比例范围。不同树高范围的腰果树分布的蚁巢数量不同,但差异不显著。而不同树高范围的腰果树上分布的长结织叶蚁蚁巢平均高度则显著差异,分布在树高10～11 m腰果树上的蚁巢平均高度最高（5.19 m）,显著高于其它树高范围的腰果树。腰果树高度与分布其上的长结织叶蚁蚁巢数量和平均高度分别呈显著和极显著正相关。 相似文献
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在莫桑比克楠普拉省调查了白粉病对60个腰果品系果梨的为害情况。结果显示,在相同的栽培条件下,不同腰果品系的果梨受白粉病为害程度差异很大。品系AZA17/79受白粉病的为害程度最低,为害率和为害指数分别仅为3.7%和0.91%,其次为H1、M96-2.3VM、AC34、4.2VM和Local 3,为害率在9.4%～20.4%,为害指数在4.87%～10.28%。其余品系的果梨为害率和为害指数相对较高。根据本文的腰果品系对白粉病抗性的评价标准(果梨),对60个腰果品系的果梨抗白粉病进行了评价,结果表明:高抗品系有5个,分别为AZA17/79、H1、M96-2.3VM、AC34和4.2VM;抗性品系5个,分别为Local 3、B4、2.4PA、1.20VM和11.9PA;中抗品系3个,分别为CCM9-61、AC10/14和5.12PA;感病品系6个,为AC6、9.1NAS、7.1PA、1.12PA、12.8PA和12.9PA;其余41个品系均属于高感品系。说明莫桑比克推广种植的腰果品系的果梨对白粉病抗性普遍较差,容易遭受白粉病为害。 相似文献
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在田间自然发生条件下,研究莫桑比克9个高产优良腰果品系对叶果回枯病的抗病性。结果表明:腰果品系4.1AD叶片高感,果实感病;腰果品系5.12PA叶片和果实均为感病;腰果品系CCS27和CM8均为叶片感病,果实中抗;腰果品系A103叶片中抗,果实高抗;腰果品系H1叶片高抗,果实中抗;腰果品系7.10PA、19.5AD和C5.59叶片和果实均为高抗。在参试腰果品系中,未发现叶片免疫品系,也未发现果实高感或免疫品系。 相似文献
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莫桑比克 60个腰果品系对腰果白粉病的抗性研究 总被引：1，自引：1，他引：0
为研究莫桑比克腰果品系对白粉病的抗性,筛选出对白粉病具有抗性的腰果品系.在莫桑比克楠普拉省,调查了白粉病在60个腰果品系果实上的为害状况.结果显示,同一条件下,各腰果品系坚果上的白粉病为害程度差异很大.其中,品系AC34和4.2VM受白粉病的为害程度最低,其次为AZA 17/79、B4、H1和M96-2.3VM,其余品系的坚果为害率和为害指数相对较高.根据笔者调查中腰果对白粉病抗性的评价标准,60个腰果品系中,分别有高抗品系6个、抗性品系1个、中抗品系9个、感病品系21个、高感品系23个.感病品系和高感品系共占调查总数的73.3％,说明莫桑比克推广种植的腰果品系对白粉病抗性普遍较差. 相似文献
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