Characterization of the host selection behavior of western tarnished plant bug (Lygus hesperus Knight)

The host selection behavior of Lygus hesperus was examined in a cotton-alfalfa system near Lubbock, Texas. The population dynamics of Lygus on these hosts were determined by field surveys in 2005-2007. The abundance of Lygus was significantly higher (df=1, 6; F=20.8; P=0.004) in alfalfa as compared with that in cotton fields. The host selection behavior of Lygus was further evaluated by a two-choice cage study, field marking, mowing and capture study in two cotton phenological stages (blooming, boll development). Cage study showed no significant difference (df=1, 15; F=3.43; P=0.1) between host selection behavior of male and female Lygus. Significantly higher (df=1, 30; F=266.9; P<0.001) number of Lygus chose alfalfa (81.7%) as a host compared with cotton (18.3%) in field marking study. In 2008, the seasonal intercrop movement behavior of Lygus was monitored weekly for 9 weeks by field marking of hosts with protein markers, capturing Lygus and detecting markers by Enzyme Linked Immuno Sorbent Assay (ELISA). There was a large amount of two directional movements of Lygus between these two crops but the net movement of adult Lygus from alfalfa into cotton was highest (500 Lygus per ha) in 12 weeks after cotton planting. The season-long physical tracking of intercrop movement of Lygus between these two hosts provided us a better understanding of the seasonal dynamics of Lygus host plant interaction which should aid in making better informed Lygus management decisions.