Alternative prey and biological control of lygus bugs (Hemiptera: Miridae) in alfalfa seed

Alternative Prey and Biological Control of Lygus Bugs (Hemiptera: Miridae) in Alfalfa Seed Tiecoura Traore and James D. Barbour Southwest Idaho Research Extension Center, Parma, Canyon Co., ID University of Idaho Lygus bugs (Hemiptera: Miridae) are the most important insect pests in alfalfa seed production in the U.S. and are managed primarily with organophosphate, carbamate and pyrethroid insecticides. Effective biological control could help reduce negative impacts of lygus bug management on pollinators of alfalfa, and lygus bug natural enemies, and delay or prevent the development of insecticide resistance. Two major predators of lygus bugs in alfalfa seed are bigeyed bugs (Geocoris spp.) and damsel bugs (Nabis spp.). There is little information concerning the influence of alternative prey on lygus bug biological control provided by these generalist predators. The goals of this study were to conduct greenhouse experiments determining 1) the impact of bigeyed bugs and damsel bugs alone and in combination on lygus bug (Lygus hesperus (Knight) populations in the presence and absence of alternative prey (pea aphid, Acyrthosiphon pisum). Our results to date have shown that higher lygus bug survival is associated with a combination of high aphid numbers and no predators, while the lowest lygus bug survival was associated with high numbers of predators in combination.