ABSTRACT

The tarnished plant bug, Lygus lineolaris, and western tarnished plant bug, L. hesperus, have been known to be key pests of cotton in several States in the Cotton Belt. In addition to these two species, a third species, Lygus elisus, has been identified to be an equally prevalent species of Lygus in the Texas High Plains. The objectives of this project were to identify the non-cotton host plant sequence prior to cotton planting and to establish the relationship between noncotton host plants and Lygus migration to adjacent cotton. Lygus bugs were recorded from 26 noncotton host plants that were sampled along the roadside in the Texas High Plains. Lygus species identification has not been completed, but it appears that L. elisus and L. hesperus are the two dominant species in the Texas High Plains Lygus complex, with occasional occurrence of L. lineolaris. The mid-April survey showed that wild mustard, redstem filaree, and alfalfa were the dominant hosts that supported Lygus bugs. When mustard senesced and alfalfa began to bloom in mid-May, alfalfa, yellow sweetclover, woolyleaf bursage, prickly lettuce, curly dock, Russian thistle, field bindweed, broomweed, ragweed, pigweed, and gaura supported Lygus populations. The mid-June survey indicated that alfalfa and yellow sweetclover were still the dominant hosts prior to cotton squaring, while Russian thistle and wild sunflower supported a significant population in areas where alfalfa was not very lush. In late July, overall Lygus numbers in wild hosts declined, with alfalfa, pigweed, Russian thistle, and silverleaf nightshade support-ing a small number of Lygus. In early September, alfalfa continued to be the most attractive host for Lygus. Lygus abundance in cotton was 0.5 adults per 100 sweeps compared with 2.5 per 100 sweeps in alfalfa in late July. Lygus abundance in cotton remained the same from late July to early September, when alfalfa became more attractive for Lygus. Preliminary data suggest that in the Texas High Plains a host sequence exists for Lygus to move from noncotton hosts to cotton and back to noncotton hosts.