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Carbamate and pyrethroid resistance in the leafminer parasitoid Diglyphus begini (Hymenoptera: Eulophidae)

Rathman, R.J., Johnson, M.W., Rosenheim, J.A., Tabashnik, B.E.
Journal of economic entomology 1990 v.83 no.6 pp. 2153-2158
parasites, Diglyphus begini, oxamyl, plant pests, fenvalerate, Liriomyza, insecticide resistance, permethrin, methomyl, Hawaii
Populations of Diglyphus begini (Ashmead), a parasitoid of Liriomyza spp. leafminers, showed resistance to oxamyl, methomyl, fenvalerate, and permethrin in laboratory bioassays. Relative to a susceptible strain from California, maximum resistance ratios for these pesticides were 20, 21, 17, and 13, respectively. Three populations that had been treated frequently with insecticides were significantly more resistant to all four insecticides compared with an untreated Hawaii population and a California population with an unknown spray history. Parasitoids from a heavily sprayed tomato greenhouse on the island of Hawaii had LC50's for permethrin and fenvalerate that were 10 and 29 times higher than the field rate, respectively. Populations resistant to oxamyl and methomyl had LC50's two- and sixfold below the field rate, respectively. D. begini is one of the few parasitoids resistant to pyrethroids, with LC50's exceeding field application rates. Resistant D. begini may be useful for controlling leafminers in management programs that integrate biological and chemical controls.