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Monitoring of insecticide resistance in Phyllonorycter mespilella (Lepidoptera: Gracillariidae) in four western states

Varela, L.G., Shearer, P.W., Jones, V.P., Riedl, H., Welter, S.C.
Journal of economic entomology 1997 v.90 no.2 pp. 252-260
orchards, monitoring, azinphos-methyl, oxamyl, Phyllonorycter, leafminers, bioassays, esfenvalerate, insect control, insecticide resistance, mortality, Oregon, California, Utah
A 4-state regional survey was conducted to assay for insecticide susceptibility in Phyllonorycter mespilella (Hubner) to azinphosmethyl, oxamyl, and esfenvalerate. Levels of insecticide susceptibility were determined using a topical bioassay on male moths collected in the field with pheromone traps in California, Oregon, Utah, and Washington. Of the populations of adult male P. mespilella tested, all but the population of Saint Cloud, WA, were resistant to azinphosmethyl. All populations tested were susceptible to oxamyl. Approximately 15% of the individuals within the Saxton population in California were resistant to esfenvalerate. An egg bioassay indicated that azinphosmethyl did not provide effective control at commercial application rates. In larval bioassays, oxamyl at 0.30 g (Al)/liter was shown to control 99% of the Saxton population, whereas no mortality was detected with azinphosmethyl or fenvalerate at commercial application rates.