Factors Influencing the Use of Trap Plants for the Control of Frankliniella occidentalis (Thysanoptera: Thripidae) on Greenhouse Potted Chrysanthemum

Western flower thrips (Frankliniella occidentalis (Pergande), Thysanoptera: Thripidae) are a major pest of greenhouse ornamentals. Insecticides are the main control measure used for F. occidentalis on ornamentals and impede the use of biological control in the greenhouse. Flowering chrysanthemums, Dendranthema grandiflora (Tzvelev), could be used as trap plants (i.e., plants that are more attractive to a pest than the crop) in an integrated pest management (IPM) program for the control of F. occidentalis on potted chrysanthemum in greenhouses. This study focused on certain behavioral characteristics of F. occidentalis that can influence the efficiency of the trap plant strategy. First, host plant selection of adult F. occidentalis was studied by determining the influence of distance and stage of the crop on the attractiveness of flowering chrysanthemum as trap plants. Second, the influence of F. occidentalis colonization (resident versus dispersing F. occidentalis) on trap plant efficacy was determined. Flowering chrysanthemum plants were more attractive to adult F. occidentalis than the vegetative, bud, and crack-bud plant stages up to distances of 12 m, and trap plants were more effective at attracting dispersing F. occidentalis than resident F. occidentalis. It is concluded that flowering chrysanthemums have potential as trap plants for F. occidentalis in potted chrysanthemum before flowering.