Evaluation of Sequential Foliar Insecticides for Control of Plant Bugs in Cotton, 2014 *

Selected insecticide treatments were evaluated for control of tarnished and clouded plant bugs in blooming cotton at the West Tennessee Research and Education Center (Jackson, TN). Cotton was planted on 5 May. The test was arranged in an RCB design with four replicates. Individual plots were 12.67 × 35 ft and planted at a rate of four seeds per row ft. Treatments were applied with a high-clearance sprayer calibrated to deliver 9.4 gpa at 40 psi with 8001 flat fan nozzles. The first application was made 22 Jul (Appl A) to cotton when plant bugs exceeded threshold. A second application was made (29 Jul, Appl B) as populations in all treatments exceeded the economic threshold of six plant bugs per 10 row feet. Plots were sampled with a standard 2.5 × 2.5 ft black cloth shake sheet by placing the sheet between two rows and vigorously shaking plants to dislodge insects. On each date, two shake sheet samples were taken on the center two rows (10 row ft total) of all plots. Plant bug control was evaluated 28 Jul, 6 days after initial treatment (Appl A, 6 DATA); and 4 Aug, 6 days after the second treatment (Appl B, 6 DATB). Yield was taken 8 Oct by harvesting the two center rows with a spindle picker. Data were subjected to ANOVA and means were separated using a protected LSD.

The vast majority of plant bugs present were immature tarnished plant bugs, although a few clouded plant bugs were also present. All insecticide treatments provided significant reduction in plant bug numbers compared with the untreated check at both evaluation timings ( Table 1 ). Orthene, Transform, and the higher rate of Dimethoate provided better control of plant bugs at 6 DATA than did Vydate. At 6 DATB, Orthene and the higher rate of Dimethoate significantly reduced plant bug numbers compared with Vydate and Transform. All insecticide treatments yielded more than the untreated check. Bidrin and Orthene treatments yielded more than either rate of Dimethoate. No phytotoxicity was observed with any treatment.

Author notes