Arthropod Management Tests 2010, Vol. 35
doi: 10.4182/amt.2010.F13
F13 COTTON: Gossypium hirsutum (L.), ‘DP 555 BG/RR’ EVALUATION OF SELECTED ACARICIDE AND ADJUVANT COMBINATIONS AGAINST SPIDER MITES IN COTTON, 2009 Jarrod T. Hardke LSU AgCenter Department of Entomology 404 Life Sciences Bldg. Baton Rouge, LA 70803 Phone: 225-578-1839 Fax: 225-578-1643 E-mail:
[email protected] P. Price E-mail:
[email protected] J. H. Temple E-mail:
[email protected] B. R. Leonard E-mail:
[email protected] J. Sharp E-mail:
[email protected] Twospotted spider mite (TSM): Tetranychus urticae (Koch) Strawberry spider mite (SSM): Tetranychus atlanticus (McGregor) An acaricide efficacy trial was conducted at the Northeast Research Station near St. Joseph, LA (Tensas Parish). Cotton seeds were planted into a Commerce silt loam on 1 May. Plot size was four rows (40-inches on centers) X 50 ft in length. Treatments were arranged in a completely randomized design with four replications. Insecticides were applied to cotton at the eight NAWF (mainstem nodes above the uppermost first sympodial position white flower) growth stage, with plant height averaging 36 inches. Treatments were applied with a high-clearance sprayer and compressed air system calibrated to deliver 12 gpa through TeeJet TX-10 hollow cone nozzles (2/row) at 48 psi. Insecticides were applied on 30 Jun, and post-treatment evaluations were made on 2 Jul (2 DAT) and 8 Jul (8 DAT). Insecticide efficacy was evaluated by recording the number of mites per one in2 on the abaxial surface of ten randomlyselected leaves within the upper ten mainstem nodes. Data were analyzed with ANOVA and means separated according to DNMRT. The test area received 1.65 inches of rain during the testing period. TSM accounted for approximately 90% of the total spider mite population across the test area prior to treatment. Infestations averaged approximately 80-150 mites per 10 in2 of abaxial leaf surface, and discolored leaves were common. Spider mite numbers varied among treatments at 2 DAT, but were significantly lower in all insecticide-treated plots compared to that in untreated plots, except those treated with Agri-flex. Numbers at 8 DAT were significantly lower in all insecticide-treated plots compared to that in untreated plots. No significant rate response was observed for Oberon or Zoro. The addition of non-ionic surfactant and UAN (N fertilizer) did not significantly improve the efficacy of Oberon. No phytotoxicity was observed with any treatment during these tests.
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Arthropod Management Tests 2010, Vol. 35
doi: 10.4182/amt.2010.F13
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Spider mites (no./10 in ) Treatment/ Formulation 1
Oberon 4SC 1 Oberon 4SC 1,2 Oberon 4SC 1,2 Oberon 4SC 3 Zoro 0.15EC 3 Zoro 0.15EC 3 Zephyr 0.15EC 1 Agrimek 0.70SC Agri-flex 1.55SC Non-treated P>F (ANOVA)
Rate/acre lb (AI)
2 DAT
8 DAT
0.125 0.188 0.125 0.188 0.0117 0.0234 0.0117 0.0096 0.0574 ---
75.3bcd 79.0bcd 58.3cd 76.3bcd 61.8cd 39.8d 59.0cd 85.5bc 105.3ab 140.3a
24.0bcd 16.3cd 12.3cd 24.3bcd 14.3cd 6.0d 11.0cd 37.5bc 43.8b 103.3a
