INFLUENCE OF INDUCED PLANT DEFENSES IN COTTON AND TOMATO ON THE EFFICACY OF BACULOVIRUSES ON NOCTUID LARVAE

Constitutive phenolase activity of plants has a profound ability to mo dulate disease in insects caused by baculoviruses. We investigated the influence of damage-induced plant phenolic oxidases in cotton and tom ato on mortality caused by two different baculoviruses in their respec tive hosts, Heliothis virescens (L.) and Helicoverpa tea (Boddie). For both plant species, peroxidase (POD) and phenolic levels were predict ive of larval mortality caused by baculoviruses. The higher the POD ac tivity, the lower the mortality in both hosts. Different classes of ph enolics (e.g., monohydroxyphenolics vs. catecholic phenolics) in combi nation with POD activity had different effects on the severity of vira l disease depending upon mixture, which implies that viral efficacy is predictable only if total chemical content of the plants is specified . Inhibition of baculoviral disease by plant phenolase activity has po tential implications for the compatibility of baculoviruses with induc ed resistance in IPM programs.