Evaluating Insecticide Efficacy Against Cotton Aphid in Cotton, 2017

This test was conducted at the Texas A&M AgriLife Research and Extension Center in Lubbock, TX. The field was planted on 18 May on 40-inch row spacing. The field was irrigated using flood irrigation. The experiment was designed as a randomized complete block (RCB) with five treatments and four replications. The plots were four-rows wide × 40 ft in length. Insecticide treatments were applied on 11 Sep at five nodes above white flower stage of cotton. Insecticides were applied to the middle two rows of each plot. Insecticide applications were made with a CO₂-pressurized hand-boom sprayer calibrated to deliver 15 gpa through hollow cone TeeJet TXVS6 spray tip nozzles (2 per row) at 30 psi. Treatments were evaluated by counting the number of cotton aphids (CAs) from 10, 3rd- to 4th-node leaves (upper canopy leaf) and 10 leaves from the lower 50% of the plant canopy (lower leaf canopy) per plot on 14 Sep (3 DAT). Data were analyzed by analysis of variance (ANOVA) and means were separated by Tukey’s mean separation.

At 3 DAT, all insecticidal treatments, except Centric 40WG, resulted in significantly fewer CAs than the untreated check on the upper leaves. On lower leaves, however, only Sivanto-treated plots had significantly fewer CAs than the untreated plots. The average number of CAs per leaf in plots treated with Centric 40WG did not vary significantly from that in the untreated plots. This research was supported in part by industry gifts of pesticides and research funding.