Evaluation of Foliar Insecticide Applications for Control of Kurtoma Thrips in Cotton, 2018

The field trial was conducted on a commercial cotton field near Wellman, TX. The field was planted on 28 May 2018 (Variety: DP1549B2XF) on 40-inch centers under dryland conditions. The experiment was designed as a RCB with six treatments and four replications. The plots were 2-rows wide × 40 ft in length. Pretreatment counts were taken on 19 Sep at 3 nodes above white flower stage of cotton and treatments were applied on the same day. Insecticide applications were made with a CO²-pressurized hand-boom sprayer calibrated to deliver 10 gpa through hollow cone TeeJet TXVS6 spray tip nozzles (2 per row) at 30 psi. Wind speed was ~9 mph during spray application. Five randomly selected leaves from each plot on each sampling date were taken to the laboratory in glass mason jars containing 75% ethyl alcohol. Samples were processed using a washing technique and the number of KT adults and immatures in each sample were counted using a dissecting microscope. Data were analyzed by ANOVA and means were separated by Tukey’s mean separation test.

There were no significant differences among treatments on 19 Sep. Average pretreatment counts ranged from 77 to 441 Kurtoma thrips (adults + immatures) per five leaves across all treatments (Table 1). At 7 DAT, all insecticidal treatments, except Admire Pro, resulted in significantly fewer number of Kurtoma thrips (adults + immatures) than the untreated check. Based on the percentage reduction in the average thrips population at 7 DAT relative to the pretreatment counts, all the insecticide treatments resulted in significantly reductions than the untreated check. At 14 DAT, only the plots treated with Intruder 70WG had significantly fewer Kurtoma thrips (adults + immatures) compared with untreated check (Table 2).

This research was supported in part by industry gifts of pesticides and research funding.