Potentiation by a granulosis virus of Gypchek, the gypsy moth (Lepidoptera: Lymantriidae) nuclear polyhedrosis virus product

Gypchek and a granulosis virus were applied in various combinations against several gypsy moth instars under field conditions, and a Blankophor BBH + Gypchek treatment was included as a comparison of virus enhancers. The residual effects of the treatments were determined over a 3-wk period. The addition of Helicoverpa armigera granulosis virus at a 1:100 dilution to Gypchek resulted in an approximate 10-fold increase in observed mortality, while the addition of Blankophor BBH at 1% resulted in an approximate 100-fold increase in observed mortality. The addition of Helicoverpa armigera granulosis virus at a 1:1000 dilution resulted in no consistent increase in recorded mortality, and the 1:100 granulosis virus dilution applied alone was inactive against gypsy moth. The residual activity of Gypchek was little enhanced by the addition of the granulosis virus at either dose.