Electrophysiological and behavioral responses of Lygus hesperus Knight (Hemiptera: Miridae) to host plant volatiles

Lygus hesperus Knight is a polyphagous pest of major concern to numerous cropping systems across western North America. Lygus hesperus exhibits well-documented host preferences which may be used to develop behavioral management strategies for this pest. This study sought to identify plant volatiles that mediate L. hesperus host preferences and assess the potential of those compounds to improve monitoring and management of this pest. Gas chromatography with electroantennographic detection was applied to identify antennally active compounds in headspace extracts from four host plants of varying attractiveness. Y-tube olfactometer assays were then conducted to determine L. hesperus responses to each of these 17 antennally active compounds individually. Six compounds attracted female L. hesperus, and subsequent tests revealed that females were attracted to an equal-parts blend of these six attractive compounds versus clean air, and that this blend was as attractive as flowering Medicago sativa. We then examined L. hesperus attraction to attractive compounds individually and an equal-parts blend of five attractive compounds in the field. An equal-parts blend of five attractive compounds was tested in strawberry, whereas the blend and each individual component were tested in alfalfa. In both field settings, neither the individual compounds nor the blend increased L. hesperus capture rates compared to unbaited control traps. Low attraction in the field could result from a masking effect of background volatiles or the failure to include important compounds in tested blends. It remains important to assess whether the compounds tested in this study may facilitate L. hesperus management in other cropping systems.