Leaf phenolic inhibition of gypsy moth nuclear polyhedrosis virus Role of polyhedral inclusion body aggregation.

Bioassays with nuclear polyhedrosis virus (NPV) administered to gypsy moth larvae on leaf disks from various tree species reveal strong viral inhibition by some tree species. Phenolic extracts from inhibitory tree leaves cause virus polyhedral inclusion bodies (PIBs) to form large aggregations. However, aggregated PIBs treated with leaf extracts and administered to larvae on laboratory diet (without phenolics) retain virulence. Our results suggest that leaf phenolics, especially hydrolyzable tannins, inhibit NPV infection, but may not act via aggregations formed in the foregut.