LIFE-STAGE SPECIFIC TOXICITY OF INSECTICIDES TO PARASITOIDS OF LIRIOMYZA-TRIFOLII (BURGESS) (DIPTERA, AGROMYZIDAE)

Adults, larvae and pupae of Diglyphus intermedius (Girault) and Neochrysocharis punctiventris (Crawford), (Hymenoptera: Eulophidae), parasitoids of the leaf-miner Liriomyza trifolii (Burgess) (Diptera: Agromyzidae), were exposed to methomyl, permethrin, methamidophos, thiodicarb, endosulfan, fenvalerate, abamectin, Bacillus thuringiensis var. kurstaki and cyromazine in the laboratory. Permethrin and methomyl were highly toxic to all life stages of both parasitoids while methamidophos was highly toxic to adults but was less toxic to larvae and pupae. Endosulfan tended to be highly toxic to N. punctiventris but less toxic to D. intermedius. Thiodicarb, fenvalerate and abamectin tended to be less detrimental to at least some life stages of both parasitoids compared with methomyl, permethrin, methamidophos or endosulfan. B. thuringiensis and cyromazine generally were the least toxic to all life stages, especially of D. intermedius. The implications for field identification of leaf-miner parasitoids in making decisions regarding insecticide use within pest management programmes are discussed.