(F22) COTTON: Gossypium hirsutum L., 'Stoneville 4646 B2R' EVALUATION OF NEONICOTINOIDS AND FLONICAMID AGAINST COTTON APHIDS AND TARNISHED PLANT BUGS IN COTTON, 2006 P. L. Bommireddy LSU AgCenter Department of Entomology 402 Life Sciences Bldg. Baton Rouge, LA 70803 Phone: (225) 578-1839 Fax: (225) 578-1643 E-mail:
[email protected] B. R. Leonard K. D. Emfinger P. Price LSU AgCenter Macon Ridge Research Station 212A Macon Ridge Rd. Winnsboro, LA 71295 Phone: (318) 435-2157 Fax: (318) 435-2133 Cotton aphid (CA): Aphis gossypii (Glover) Tarnished plant bug (TPB): Lygus lineolaris (Palisot de Beauvois) Selected insecticides were evaluated for control of CA and TPB at the Macon Ridge Research Station (Franklin Parish) near Winnsboro, LA. Cotton seed was planted on May 1 in a Gigger-Gilbert silt loam soil. Plots consisted of four rows (centered on 40 inches) and 50 ft in length. Treatments were arranged in a RCB design with four replications. Insecticides were applied with a tractor-mounted boom and compressed air system calibrated to deliver 10 gpa through 8001 flan fan nozzles (2/row) at 30 psi on 7 Jun. Plant terminals (40/plot) infested with colonies of CA were marked with a yellow snapon-tag placed which was placed on the main stem immediately prior to application of the insecticides. Insecticide efficacy against CA was measured by harvesting 10 (tagged) plant terminals per plot at 2 DAT, 8 DAT, and 12 DAT. The plant terminals were transported to the laboratory in plastic bags and washed to remove all CA. Numbers of CA in each plot were counted with a binocular scope. Two TPB adults were placed into an 11.5 cm × 11.5 cm nylon mesh (no. 280) bag and caged on each of 10 plant terminals per plot within 2 HAT. Percent mortality of TPB was recorded 4 DAT. All data were subjected to ANOVA and means separated according to DMRT. No rainfall occurred during the field trial. Numbers of CA exceeded 100 insects per plant terminal at test initiation. Numbers declined in all treatments during the evaluation period. All insecticides significantly reduced the number of CA compared to that in the non-treated check at 2 DAT, 8 DAT, and 12 DAT. All insecticide treatments with the exception of Carbine at the lower rate produced TPB mortality levels significantly higher than that in the non-treated check. The higher rates of insecticides generally outperformed the lower rates in reducing numbers of CA and increasing TPB mortality. No phytotoxicity was observed from any of the insecticide treatments. CA/10 plant terminals Treatment/ formulation Intruder 70WP Intruder 70WP Intruder 70WP Centric 40WG Centric 40WG Trimax Pro 4.44SL Trimax Pro 4.44SL Carbine 50WG Carbine 50WG Untreated check P > F (ANOVA)
Rate/acre lb (AI)
2 DAT
8 DAT
12 DAT
% TPB mortality 4 DAT
0.026 0.035 0.05 0.031 0.05 0.031 0.047 0.044 0.088 ---
709.5bc 713.8bc 195.0c 758.8bc 590.3bc 938.0b 718.5bc 710.8bc 724.5bc 1602.3a
168.0cd 91.0d 35.5d 182.0cd 35.8d 420.0b 292.5c 144.3cd 54.5d 848.3a
103.3bcd 52.5bcd 37.0cd 45.0bcd 23.3d 132.3bc 142.8b 108.0bcd 65.8bcd 312.0a
28.5de 41.5bcd 55.7bc 62.5ab 79.2a 37.5cd 50.0bc 8.5ef 25.0de 4.2f
< 0.01
< 0.01
< 0.01
< 0.01
Means within columns followed by a common letter are not significantly different (DMRT; P = 0.05).
