DISTRIBUTION OF THE TARNISHED PLANT BUG (HETEROPTERA, MIRIDAE) WITHINCOTTON PLANTS

The within-plant distribution of the tarnished plant bug, Lygus lineol aris (Palisot de Beauvois), in cotton, Gossypium hirsutum L., was dete rmined during June through the Ist week in August in 1992 and 1993 at Stoneville, MS. Locations of adults and nymphs in cotton were determin ed weekly using visual searches of whole plants or plant sections (mai nstem terminals, upper and lower plant halves below the mainstem termi nals). The distributions of adults and nymphs found in the morning (09 00-1100 hours) in 1992 were not significantly different from their dis tributions found in the afternoon (1300-1500 hours). Adults had a sign ificantly different distribution than nymphs on vegetative structures (mainly leaves), fruiting structures (squares, bells, and blooms) and mainstem terminals in both years. The distributions of adults and nymp hs also were significantly different in both years on the mainstem ter minals and upper and lower plant halves below the terminal. Nymphs and adults were found in both years to have 75% of their populations (on average) in the mainstem terminal plus the fruit and vegetative struct ures on the top 6 nodes of the plant. Nymphs showed a strong preferenc e for fruiting structures, and high percentages of adults were found o n vegetative structures through the first 3 wk of squaring (June throu gh the Ist week in July) in both years. Adults then became more disper sed among the vegetative structures, fruit, and mainstem terminals. Th ese types of distributions would make the drop cloth an excellent meth od for sampling nymphs, whereas the sweep net would work well for adul ts especially through the first 3 wk of squaring. If visual examinatio n of plants for nymphs and adults is used to sample cotton, it should include mainstem terminals plus vegetative and fruiting structures in the upper halves of plants.