Effects of Insecticides on Arrhenotokous and Thelytokous Types in Onion Thrips, Thrips tabaci Lindeman, in Kyoto Prefecture, Japan

Abstract

The effects of insecticides on arrhenotokous and thelytokous types in adult females of onion thrips, Thrips tabaci Lindeman, collected from a total of 13 sites of Welsh onions, cabbages, and onions in Kyoto Prefecture, Japan, in 2016 and 2017 were evaluated. Susceptibility to the tested insecticides varied among the reproductive types, populations, and years. Among the 14 insecticides tested on female adults in arrhenotokous type using the kidney bean leaf dipping method, spinetoram, spinosad, avermectin, cyantraniliprole, fluxametamide, and flometoquin were the most toxic. In addition, cypermethrin, imidacloprid, spinetoram, spinosad, avermectin, cyantraniliprole, fluxametamide, and flometoquin caused a high mortality rate in female adults in thelytokous type. Overall, the mortality rate in thelytokous type was higher than that in arrhenotokous type.