Assessment of trap crops for Lygus spp. in lettuce

The effectiveness of the use of trap crops for reducing herbivorous Lygus s pp. (Heteroptera: Miridae) in a lettuce agroecosystem was evaluated in a se ries of field experiments in two locations in Sweden. Trap crop efficacy wa s determined by comparing Lygus densities in plots of lettuce with densitie s in adjacent plots of the cover crops Melilotus officinalis, Vicia sativa, Trifolium pratense and Medicago sativa, and the weed Artemisia vulgaris. A ll of the trap crops tested were more attractive to Lygus than lettuce, wit h between five- and 30-times as many adult Lygus on cover crops and more th an 100-times more on A. vulgaris. Lygus rugulipennis was the dominant speci es on all plant species. These results suggest that a wide range of trap cr ops, including nitrogen-fixing cover crops, may be suitable for reducing po pulations of Lygus spp. in lettuce cropping systems.