EVALUATION OF INSECTICIDES AGAINST COTTON APHIDS ON COTTON, 2009-2010

Selected insecticides were evaluated for control of cotton aphid, Aphis gossypii (Glover), at the Macon Ridge Research Station near Winnsboro, LA (Franklin Parish). Cotton seed, Deltapine 555 BG/RR, was planted into a Gigger silt loam soil on 15 May in 2009 (Test 1) and 10 May in 2010 (Test 2 & 3). Plot size was four rows (centered on 40-inches) and 50 ft. long. Treatments were placed in a RCBD with four replications. Thirty plant terminals infested with cotton aphids were tagged prior to insecticide applications in all tests. Insecticides were applied on 17 Jun (2009) in Test 1 and on 22 Jun and 25 Jun (2010) in Tests 2 and 3, respectively. Insecticides were applied with a CO2-charged backpack spray system calibrated to deliver 10 gpa through TeeJet® TX-9 hollow cone nozzles (2/row) at 45 psi. Treatment efficacy against cotton aphids was measured by harvesting 10 tagged plant terminals per plot at 2, 7, and 14 DAT in Test 1 and at 2 and 7 DAT in Tests 2 and 3. Plant samples were processed using whole-plant washing procedures to remove aphids. Cotton aphids were counted using a dissecting microscope. Data were subjected to ANOVA and means separated according to LSD. No rainfall occurred during Test 1 and 0.12 inches of rainfall occurred during Tests 2 and 3.