Toxicity of azinphos-methyl to various development stages of the codling moth Cydia pomonella (Lepidoptera: Tortricidae).
The response to azinphos-methyl of different life-stages of the codling moth Cydia pomonella (L.) was studied. A similarity in response to azinphos-methyl (LC(50), LC(90)) was observed in neonate larvae obtained from the first and second generations of field populations. Mortality rates for neonate larvae of a field population cross-bred with a laboratory colony were lower (by a factor of 1.2-2.2) in comparison with field neonate larvae. The mortality rate of larvae from a laboratory colony exposed to artificial diet containing azinphos-methyl gradually decreased at older instars. The mortality rates of fifth-instar larvae were remarkably low when exposed to artificial diet mixed with azinphos-methyl or when topically treated with the insecticide. One- to three-day-old females were more sensitive than males of the same age, whereas the opposite was observed in 14-to 17-day-old adults. Mortality rates of 14- to 17-day-old adults were higher than those under 10 days old. No significant difference in sensitivity to the organophosphorus compound was noticed between the sexes of 7- to 10-day-old adults. Neonate larvae of the codling moth can serve as a target life-stage for various groups of pesticides, and the importance of using such a stage as a standardized methodology for monitoring resistance in the codling moth is discussed.
Reuveny
Haim
H
Migal Northern R&D, Integrated Pest Management Centre (IPMC), Kiryat Shmona 11016, Israel. haimr@yiorn.org.il
Cohen
Ephraim
E
D000367:Age Factors; D000818:Animals; D001387:Azinphosmethyl / Q000633:toxicity*; D001681:Biological Assay; D004351:Drug Resistance; D005260:Female; D007300:Insect Control / Q000379:methods*; D007306:Insecticides / Q000633:toxicity*; D007814:Larva; D007928:Lethal Dose 50; D008018:Life Cycle Stages / Q000187:drug effects*; D008297:Male; D009036:Moths / Q000254:growth & development*; D012737:Sex Factors
D007306:Insecticides; D001387:Azinphosmethyl