Efficacy of Selected Insecticides Against Field Populations of Beet Armyworm, 1995

Field tests were conducted at the Northeast Research Stations located at St. Joseph and Winnsboro, LA to evaluate the efficacy of 3 registered and 3 experimental insecticides against beet armyworms on cotton. Each test was arranged in a RCBD and replicated 4 times with plots of 4 rows (40 inch centers) by 50 ft. In Test I, cotton (‘Stoneville LA 887’) was planted on 16 May. In Test I cotton (‘DPL 5690’) was planted on 20 Jun. Treatments for Tests I and II were applied with a high clearance sprayer on 15 and 30 Aug, respectively. In Test I, the sprayer was calibrated to deliver 10 gpa through Teejet X-12 hollow cone nozzles (2/row) at 52 psi. In Test II, the sprayer was calibrated to deliver 11.3 gpa through Teejet X-8 hollow cone nozzles (2/row) at 44 psi. Treatment efficacy was determined by taking 2 drop-cloth 3 ft2 samples of a single treated row. Samples were taken at 3, 5, 7 and 10 DAT on rows 1, 2, 3 and 4, respectively. Data were analyzed using ANOVA followed by means separation according to Fischer’s Protected LSD. No rainfall occurred during the experimental period in Test I. Only a trace (< 0.05 inches) of rainfall was recorded during the experimental period in Test II at 7 DAT and it was not considered sufficient to affect insecticide efficacy.