Evaluation of an Insecticide Rescue Treatment Against Bollworm, 1997

The efficacy of selected insecticide treatments was evaluated against an established infestation of BW at the Macon Ridge location of the Northeast Research Station. Cotton seed was planted 29 May in plots consisting of 4 rows (40-inch centers) X 50 ft. Treatments were arranged in a RCB design and replicated 6 times. Applications were made with a high-clearance sprayer and CO2-charged system calibrated to deliver 6 gpa through Teejet TX-8 hollow-cone nozzles (2/row) at 47 psi. Insecticides were applied on 6 Aug. Treatments were evaluated using two methods. In the first, 5 BW larval infested bolls were removed from each plot 2 h after treatment, placed in 20-ml plastic vials, and transported to the laboratory. Mortality of BW larvae was determined at 2 DAT and 4 DAT. In the second procedure, a field sample of 100 random bolls was taken from each plot and examined for damage and live larvae at 5 DAT. Rainfall did not influence the efficacy of these treatments. Data were analyzed with ANOVA and means were separated according to DMRT.