Abstract
An experiment was conducted in screened houses to examine the effect of insecticides on density suppression of the oriental tea tortrix, Homona magnanima Diakonoff, by an egg parasitoid, Trichogramma dendrolimi Matsumura. Ethiprole-thiacloprid, with low insecticidal activity against T. dendrolimi, was sprayed in plot A, and tolfenpyrad, with high insecticidal activity against T. dendrolimi, was sprayed in plot B. Ethiprole-thiacloprid was significantly less harmful to parasitism of H. magnanima eggs by T. dendrolimi than tolfenpyrad. The density of H. magnanima larvae tended to be affected by differences in insecticides, but no significant difference was observed between Plot A and B. These results suggested that ethiprole-thiacloprid was less harmful to density suppression of H. magnanima by T. dendrolimi than tolfenpyrad.
