TOPICAL PHEROMONE TRAP ASSAY FOR MONITORING INSECTICIDE RESISTANCE OFPHYLLONORYCTER ELMAELLA (LEPIDOPTERA, GRACILLARIIDAE)

A topical pheromone trap assay was an effective method for assessing t he resistance status in male Phyllonorycter elmaella (Doganlar and Mut uura) moths to the organophosphate azinphosmethyl and the carbamate ox amyl. Moths captured in pheromone-baited sticky traps were treated top ically with a 0.2-mu l droplet of an insecticide solution, which was d ispensed with a microsyringe to each insect. Several factors affected the mortality response of adults including trap adhesive, environmenta l conditions before and during the bioassay, prior field exposure to i nsecticide, and time of collection. The trap adhesives, Tanglefoot and Tangletrap, were inherently less toxic to captured moths than Stikem Special. High temperature and low humidity in the field before collect ion or later during the bioassay increased mortality. Sublethal exposu re to azinphosmethyl or oxamyl in the field also increased the mortali ty response of moths in the biosassays. Control mortality increased to ward the end of each flight period and with each generation. Leaf-mine rs from sprayed orchards were highly resistant to azinphosmethyl but a re still susceptible to oxamyl. We detected no evidence for cross-resi stance. Male and female moths were equally susceptible to oxamyl. In c onclusion, this pheromone trap assay can provide rapid information on the susceptibility of P. elmaella populations to adulticides and help to select effective control options.