Movement of Lygus hesperus and associated natural enemies in trap-cropped strawberries

Alfalfa (Medicago sativa L.) trap crops are used to reduce Lygus hesperus Knight damage in strawberries on the California Central Coast. To determine the movement patterns of L. hesperus, the parasitoid Peristenus relictus and generalist predators in this system, a mark-capture technique using milk and egg-white protein sprays was utilized. Insects with positive ELISA marks were generated from milk, egg-white and “double positive” samples and were captured in alfalfa trap crops and adjacent strawberry rows. Movement patterns during this experiment demonstrated that L. hesperus preferred alfalfa trap crops relative to adjacent strawberry plants. Larger proportions of natural enemies moved from trap crops into neighboring vs. distant strawberries.