Assessment of the Lethal and Parasitism Effects of Helicoverpa armigera Nucleopolyhedrovirus (HaNPV) on Trichogramma chilonis (Ishii) (Hymenoptera: Trichogrammatidae)

Studies were conducted in the laboratory to assess the effects of Helicoverpa armigera nucleopolyhedrovirus (HaNPV) applied to eggs of Sitotroga cerealella Olive, on emergence of and parasitism by female Trichogramma chilonis (Ishii) emerged from HaNPV- treated host eggs. The percent emergence (mean) of tiny parasitoid from host eggs treated during egg, larval and pupal stages with the virus at field dose (x), 2x dose, and 0.5x dose ranged from 83.2- 87.3%, 87.1- 91.6%, and 83.7- 89.7%, respectively, relative to control eggs treated with water. The parasitism rates by female parasitic wasps emerged from host eggs treated at x dose when parasitoid was during egg, larval, and pupal stages were 21.6, 26.5, and 25.1%, respectively; the 2x dose resulted in parasitism (mean) of 23.1, 27.6, and 26.1 when parasitoids were treated in egg, larval, and pupal stages, respectively, while, 0.5x dose led to 21.0, 25.9, 27.7, mean parasitism, respectively. The percent reduction in both emergence (mean) and parasitism (mean) relative to the controls was less than 10% for all doses and life stages treated, indicated that HaNPV is harmless (E 30%) to the emergence as well as parasitism efficiency of T. chilonis emerged from treated host eggs.