(F43) COTTON: Gossypium hirsutum L., ‘DPL 493’ EVALUATION OF SELECTED INSECTICIDES AGAINST HELIOTHINES IN COTTON, 2004 K. D. Emfinger LSU AgCenter Macon Ridge Research Station, Winnsboro, LA 71295 Phone: (318) 435-2157 Fax: (318) 435-2133 E-mail:
[email protected] K. Tindall B. R. Leonard J. H. Temple LSU AgCenter Department of Entomology Baton Rouge, LA 70803 Bollworm (BW): Helicoverpa zea (Boddie) Tobacco budworm (TBW): Heliothis virescens (F.) Cotton seed were planted 5 Jun in plots consisting of four rows (centered on 40 inches) × 50 ft. Treatments were arranged in a RCB design and replicated four times. Insecticides were applied with a hiclearance sprayer and CO2 charged system calibrated to deliver 6 gpa through Teejet TX-8 hollow cone nozzles (2 per row) at 48 psi. Insecticides were applied on 23, 28 Jul, and 1 Aug. Treatments were evaluated by examining 50 flower buds (squares) per plot on 27, 31 Jul, and 5 Aug, for evidence of bollworm (BW) and tobacco budworm (TBW) damage and squares infested with larvae. Data were analyzed with ANOVA, and means were separated according to Tukey’s test (P ≤ 0.05). Larvae in the plots consisted of a mixed population of BW and TBW, but TBW represented the dominant (>75%) species during the test. Plots treated with S-1812 + Baythroid, S-1812 + Mustang Max, S-1812 + Karate-Z, and Tracer had significantly fewer damaged squares compared to the untreated check plots on 27 Jul. All insecticide treatments, except Baythroid, significantly reduced the number of damaged squares compared to that in the untreated check on 31 Jul. All insecticide treatments except S-1812 + Karate and Baythroid alone, had significantly fewer damaged squares compared to the untreated plots on 5 Aug. For the test mean, all insecticide treated plots had fewer damaged squares compared to that in the untreated plots. On 27 Jul, all insecticide treated plots, except those treated with S-1812 + Baythroid, Baythroid, and Steward had significantly fewer larvae compared to the untreated plots. There were no significant differences among treatments on 31 Jul. On 5 Aug and for the test mean, all treatments except Baythroid, significantly reduced the number of larvae compared to the untreated control. No phytotoxicity from any insecticide was observed in this test.
BW and TBW damage/50 squares Treatment/ formulation S-1812 4EC + Baythroid 2EC S-1812 4EC + Mustang Max 0.8EC S-1812 4EC + Karate 2.08EC Tracer 4SC Baythroid 2EC Steward 1.25SC Untreated check (P > F)
Rate lb (AI)/acre 0.1 + 0.028 0.1 + 0.018 0.1 + 0.025 0.063 0.028 0.09 ---
BW and TBW larvae /50 squares
27 Jul
31 Jul
5 Aug
Test mean
27 Jul
31 Jul
5 Aug
Test mean
6.8b
3.8b
3.0b
4.5c
1.5ab
0.8a
0.3b
0.8bc
8.0b
1.8b
2.5b
4.1c
1.0b
0.3a
0.0b
0.4c
7.3b 8.0b 12.5ab 12.0ab 16.3a
4.3b 4.3b 5.0ab 4.3b 9.3a
3.3ab 2.5b 5.3ab 2.5b 6.0a
4.9bc 4.9bc 7.6b 6.3bc 10.5a
0.5b 0.8b 3.5ab 1.3ab 4.3a
1.0a 0.3a 1.5a 0.8a 2.3a
0.0b 0.3b 0.8ab 0.0b 1.5a
0.5c 0.4c 1.9ab 0.7c 2.7a
