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Alan R. McCaffery Jonathan W. Holloway Richard T. Gladwell 《Pest management science》1995,44(3):237-247
Spontaneous neuronal activity was recorded from the peripheral nerves of third-instar larvae of strains of Heliothis virescens (F.) obtained directly from cotton fields in the USA. Following a control period the preparations were exposed to increasing concentrations of cis-cypermethrin in a cumulative dose-response assay. A positive response was defined as an increase of at least five-fold in the rate of neuronal activity over that seen during the control period. Up to 35 individuals of each strain were assayed and the responses used to construct a phenotypic profile categorising the individuals from nerve-susceptible to highly nerve-insensitive. An EC50 for the action of cis-cypermethrin was also obtained. There was a positive, significant correlation between non-synergisable resistance to cypermethrin and nerve insensitivity as defined in the neurophysiological assay. It was shown that nerve insensitivity to cypermethrin increased throughout the cotton-growing season. 相似文献
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在中国科学院动物研究所提供的１１种烟草夜蛾ＨｅＬｉｏｔｈｉｓａｓｓｕｌｔａ性引诱剂合成样品中，以Ｂ，Ｄ，Ｅ３种诱蛾效果最优，Ａ，Ｃ，Ｆ次之，Ｇ，Ｈ，Ｉ，Ｊ，Ｋ较差；在同一时期内不同样品间或不同区组间的诱娥高峰日无显著差异；诱娥高峰日与累计蛾量达５０％的日期之间也无明显差异．本文还研究了诱蛾高峰日的蛾量与总诱蛾量的回归关系及诱蛾高峰日与下一代卵孵化高峰日的关系． 相似文献
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A GC-MS method capable of completely separating the four pairs of diastereoisomers of cyfluthrin is presented and the method used to show that isomerisation of the cyfluthrin enantiomers occurs in methanol. This methanol-induced isomerisation could also be demonstrated by bioassays using water fleas. The biological activities of the various cyfluthrin isomers contained in the commercial products cyfluthrin and beta-cyfluthrin were assayed using several strains of lepidopteran larvae including Plutella xylostella, Heliothis virescens and Spodoptera frugiperda. With the susceptible strains, the efficiencies of the isomers mixtures of cyfluthrin and beta-cyfluthrin were shown to obey the rules of additivity. However, in tests with a resistant strain of P. xylostella originating from Thailand, the ‘inactive’ isomer III acted synergistically with the active isomer IV. Resistance factors in strains of H. virescens and P. xylostella were found to be higher with cis than with trans isomers. This probably contributes to the superior action of cyfluthrin and beta-cyfluthrin against various pests of agricultural importance since the commercial products contain a high content of trans isomers (‘high trans pyrethroids’). 相似文献
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David G. Heckel Linda J. Gahan Fred Gould Joanne C. Daly Stephen Trowell 《Pest management science》1997,51(3):251-258
Genetic linkage maps of Heliothis virescens and Helicoverpa armigera are being used to identify and characterize resistance-conferring genes. The insensitive acetylcholinesterase conferring resistance to organophosphorus insecticides and the insensitive sodium channel conferring resistance to pyrethroids have both been mapped in H. virescens. The linkage mapping approach permits a genetic dissection of resistance, even when the mode of action and lethal target are not precisely known, such as for the insecticidal toxins from the bacterium Bacillus thuringiensis (Bt). We have identified and mapped a major Bt-resistance locus in a strain of H. virescens exhibiting up to 10000-fold resistance to Cry1Ac toxin and are currently developing a linkage map for H. armigera with a set of ‘anchor’ loci to facilitate comparison with H. virescens. Both species are currently experiencing their first significant selective pressure in the field by transgenic cotton expressing Cry1Ac, and timely identification of resistance mechanisms and their underlying genetic basis will be essential in successfully managing the Bt resistance that will eventually appear. ©1997 SCI 相似文献
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Adult and third-instar larval Heliothis virescens were examined for nerve insensitivity to cis-cypermethrin using a rapid and robust neurophysiological method. Three laboratory strains, BRC susceptible, PEG-87 resistant and MS2 metabolic resistant, were compared with a series of pyrethroid-resistant strains collected from a field site in Louisiana, USA, during the 1992 cotton season. Nerve insensitivity was present in a proportion of the individuals in both the PEG-87 and the field strains, at both life stages, minimal in the MS2 strain and absent in the BRC strain. Frequencies of nerve-sensitive and nerve-insensitive individuals in each strain were not significantly different at the two life stages examined. 相似文献
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