Insecticde Efficacy for Thrips Management in Cotton, 2022

On 30 May, a foliar efficacy trial was conducted in Starkville, MS, on the R.R. Foil Plant Research Facility to evaluate selected insecticides targeting tobacco thrips populations. Plot size was four rows wide by 40 feet in length on 38-inch centers. Field studies were established as a randomized complete block design with four replications. Insecticide treatments included Intrepid Edge 3SC, Orthene 97, Bidrin 8, Dimethoate 4EC, Radiant 1SC, and an untreated control (UTC). All treatments were applied according to current thresholds with reference to the Mississippi Insect Control Guide concerning one to two leaf stage cotton. Treatments were applied using a tractor-mounted sprayer calibrated to deliver 10.0 GPA at 60 PSI through TX-6 Hollow Cone nozzles. Plots were sampled 4 and 8 days after treatment (DAT) by cutting five plants from the center two rows at random. Plants were washed with a Clorox and soap solution removing thrips onto filter paper to be counted using a microscope. Data were analyzed with ANOVA and means were separated using Fisher’s Protected LSD (P ≤ 0.05).

At first sampling 4 DAT, there were no significant differences when comparing Dimethoate 4EC to the untreated check (Table 1). However, Radiant 1SC provided significant control when compared with the Dimethoate 4EC and the untreated check (Table 1). All other treatments significantly reduced populations compared to the untreated check at 4 DAT (Table 1). There were no significant differences among all treatments when comparing thrips population at 8 DAT (Table 1).¹

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