(F55) COTTON: Gossypium hirsutum L.; 'Deltapine 436RR' EVALUATION OF NEW INSECTICIDES FOR CONTROL OF COTTON FLEAHOPPER IN COTTON, 2002 D. A. Mott Texas Cooperative Extension 3151 Innerloop, Ste. A Georgetown, TX 78626 Phone: (512) 943-3300 Fax: (512) 943-3301 E-mail:
[email protected] C. G. Sansone Texas Cooperative Extension District 7 Extension Center 7887 US Highway 87 N San Angelo, TX 76901-9714 Phone: (325) 653-4576 Fax: (325) 655-7791 E-mail:
[email protected] Cotton fleahopper (CF): Pseudatomoscelis seriatus (Reuter) Cotton was planted on 4 Apr into a Houston clay in 38-inch rows in central TX near Coupland. The fertility and herbicide programs followed Extension recommendations for cotton in this region. Plot size was 60 ft × 4 rows with three replications in a RCB design. Insecticide applications were made on 23 May, at pinhead square, with a self-propelled CO 2 -pressurized sprayer calibrated to deliver 8 gpa total volume at 30 psi with two TX-8 hollow cone nozzles per row. The adjuvant Kinetic (0.25% v/v) was added to the Trimax treatments and Intruder was applied with Agri-dex, a crop oil concentrate (COC) (0.5% v/v). Treatments were evaluated by counting the number of CF (nymphs and adults) and predators on 10 plant terminals on three dates after each application. Data were analyzed using ANOVA and means were separated using LSD (P ≤ 0.05). Percent control for CF was calculated using Henderson's method. Cotton fleahopper populations were consistently high throughout the trial. One day after treatment, all the treated plots had significantly lower CF numbers than the control (Table 1). However, like many trials in the Southern Blacklands, only three treatments lowered numbers below the published threshold of 15 per 100 terminals. Both rates of Centric and the low rate of Intruder with COC were effective at lowering numbers below threshold levels. Only Trimax and Steward provided less than 80 percent control. Four DAT, all the treated plots had significantly lower cotton fleahopper numbers except Steward. As in 1 DAT, only Centric and the low rate of Intruder with COC were effective at lowering numbers below threshold levels. Treatment efficacy started to decline as Steward, Orthene and Trimax provided less than 80% control. At 6 DAT, none of the plots were significantly less than the untreated control, although all treatments had lower numbers than the control. Natural enemy populations did not vary much in the plot and never significantly differed from the untreated control (Table 2). However, a general trend existed for the Orthene and Trimax treated plots to have lower numbers than the other control plots.
