Differential attraction of Lygus hesperus (Hemiptera: Miridae) to host plants in the laboratory

Lygus hesperus Knight is a generalist pest of alfalfa, strawberry, cotton, and other crops in western North America. Quantifying the relative olfactory preference of L. hesperus to different hosts and understanding the potential chemical basis of host selection could facilitate the monitoring and management of this serious pest. In this study, we examined the response of female L. hesperus to olfactory cues from 17 host plant species using flight tunnel and Y-tube olfactometer assays. We then selected 4 host plant species that elicited different responses along a gradient of low to high attraction and quantified their volatile profiles using dynamic headspace extractions and gas chromatography-mass spectrometry (GC-MS). Female L. hesperus responded to host plant volatiles in both behavioral assays with the highest proportion of female L. hesperus moving upwind when exposed to Medicago sativa. When given a choice between M. sativa and each other species individually in Y-tube assays, female L. hesperus preferred M. sativa relative to Artemisia vulgaris, Fragaria ananassa, Hordeum jubatum, Plantago major, and Capsella bursa-pastoris. The overall volatile profile of M. sativa differed statistically from the profile of C. bursa-pastoris and F. ananassa, with higher emission of various specific compounds, (Z)-β-ocimene and (E)-β-ocimene, in M. sativa. The information gathered in this study suggests a potential use of M. sativa as a trap for L. hesperus and points to specific plant volatiles to consider in the development of chemical lures for L. hesperus.