Influence of Insecticides on Oviposition Behavior of Western Tarnished Plant Bug on Strawberry

Western tarnished plant bug, Lygus hesperus Knight (Hemiptera: Miridae), is a serious insect pest of strawberry in California. Several effective insecticides are applied to manage L. hesperus in strawberry. These insecticides can induce behavioral changes to L. hesperus oviposition such as deterrence and avoidance which are poorly understood in strawberry production. This information can improve integrated L. hesperus management. The objectives of this study were to determine oviposition behavior of adult L. hesperus under 1) no-choice experiment with no insecticide-treated strawberry plant, 2) no-choice experiment with sulfoxaflor, flonicamid and novaluron-treated strawberry plant; and 3) choice experiment with non-treated and sulfoxaflor, flonicamid and novaluron-treated strawberry leaf petioles in semi-field settings. When the distribution of L. hesperus eggs within the non-treated strawberry plants were evaluated at upper, middle and lower strata of the plant as well as at various leaf parts, eggs were uniformly distributed along all three strata of the plant and most of the eggs were found on leaf petiole than on leaf blade, mid-rib or veins. In no-choice experiment, number of the eggs laid by the L. hesperus was significantly lower in the sulfoxaflor-treated than in the non-treated plants. In the choice experiment, number of eggs was significantly greater on non-treated petioles than insecticide- treated when the insecticide was novaluron. There was no difference in L. hesperus egg density between sulfoxaflor or flonicamid-treated and non-treated petioles