D3078: Effects of simulating injury by tarnished plant bug, Lygus lineolaris, to terminal growth and pre-floral buds on cotton growth and yield in South Carolina

The tarnished plant bug (TPB), Lygus lineolaris, is a growing economic concern in cotton across the southeastern United States because of feeding injury to terminal growth, pre-floral buds (squares), blooms, and small bolls. Injury to seedling cotton can result in permanent loss of fruiting sites and apical dominance, redistribution of fruit on the plant, delayed crop maturity, and loss of yield. Due to the plant’s ability to overcome early season damage from insects, simulated injury will allow reevaluation of treatment thresholds based on fruit and terminal retention for newer cotton varieties.

Cotton (DP 2127) was planted in 4-row plots with a row length and spacing of 12.2 m and 96.5 cm, respectively, at Clemson University’s Edisto Research Center in Blackville, SC, arranged in a randomized complete block design with 4 replications. Treatments on the center 2 rows of each plot, with border rows used as buffers, consisted of simulated injury by hand removal of match-head squares or terminal buds using first-aid scissors. Terminal buds were removed at 0, 10, 20, 50, 75, and 100% at the 7-node stage or first bloom. Match-head squares were removed at 0, 20, 33, 50, and 100% at the 2^nd, 4^th, or 2^ndand 4^th week of squaring. Trials were over-sprayed with insecticide (140 g/ha, sulfoxaflor, Transform 50WG) at a 10–14 day interval to minimize plant loss from injury by natural populations of TPB. Data measured included canopy height and width, crop maturity, quality, and lint yield.