Understanding and manipulating plant attributes to enhance biological control

This paper demonstrates the necessity to consider plants as an essential an d interactive component of biological control practices. Plants not only po ssess direct chemical and morphological defenses against herbivores but als o benefit from indirect defenses provided by parasitoids and predators, whi ch use herbivores as hosts or prey. Plants play an active role in the inter play between entomophagous arthropods and herbivores and actually mediate m any of the interactions, thereby influencing the intensity of protection re ceived. Herein, we review how plant attributes influence natural enemy effi ciency by providing shelter, mediating host/prey accessibility, providing h ost/prey finding cues, influencing host/prey suitability, mediating host/pr ey availability, and providing supplemental food sources for natural enemie s. In light of this crucial role, we suggest ways of manipulating morpholog ical and chemical attributes of crop plants for a more sustainable and bala nced control of insect pests in agro-ecosystems. (C) 2000 Academic Press.