Insecticide Resistance of the Cotton Aphid, Aphis gossypii GLOVER. III. Host Preference and Organophosphorus Susceptibility.

Abstract

The host preference between eggplants (Solanum merongena L.) and cucumbers (Cucumis sativus L.) in spring, and the susceptibility to fenitrothion of populations of the cotton aphid, Aphis gossypii GLOVER, overwintered on shepherd's purse (Capsella bursa-pastoris M.), speedwell (Veronica persica P.) and rosemallow (Hibiscus syriacus L.) were investigated in closed plastic minihouses at Higashihiroshima in Hiroshima Prefecture from 1988 to 1990. Two biotypes with different host plant preferences for eggplant and cucumber were observed in field populations overwintered on winter host plants such as shepherd's purse, speedwell and rosemallow. Populations transferred from eggplants to overwintering host plants preferred the original host eggplant to cucumber in the early spring. Populations transferred from cucumbers to overwintering host plants preferred the original host cucumber to eggplant. Susceptibility to fenitrothion was higher in the populations on eggplants than those on cucumbers.