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EVALUATION OF NEW INSECTICIDES FOR CONTROL OF BOLLWORM IN COTTON, 2002

EVALUATION OF NEW INSECTICIDES FOR CONTROL OF BOLLWORM IN COTTON, 2002 (F58) COTTON: Gossypium hirsutum L.; 'Deltapine 436RR' 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: c-sansone@tamu.edu D. A. Mott Texas Cooperative Extension 3151 Innerloop, Ste. A Georgetown, TX 78626 Phone: (512) 943-3300 Fax: (512) 943-3301 E-mail: d-mott@tamu.edu Bollworm (BW): Helicoverpa zea (Boddie) Cotton was planted on 10 Apr into a Houston clay in 38-inch rows in central Tx near Taylor. The fertility and herbicide programs followed Extension recommendations for cotton in this region. Plot size was 75 ft x 4 rows with four replications in a RCB design. Insecticide applications were made on 28 Jun, at first bloom, with a self-propelled CO - pressurized sprayer calibrated to deliver 8.0 gpa at 30 psi with three TX-6 hollow cone nozzles per row. The adjuvant Kinetic (0.25% v/v) was added to the Denim treatment, and Steward was applied with Agri-Dex, a crop oil concentrate (0.5% v/v). The treatments were evaluated on 1 and 5 Jul. A random plant from one of the two center rows of the plot was selected, which served as a starting point to begin making counts. Ten consecutive plants were visually inspected for number of bollworm larvae and bollworm eggs from one of the center two rows of each plot. In addition, 25 squares were randomly pulled from the center two rows of each plot and all bollworm damaged fruit was counted and recorded. Yield was taken by harvesting 1/1000 acre from each of the middle two rows of each plot. All data were analyzed using ANOVA and LSD (P ≤ 0.05). Percent control was calculated using Henderson's formula. Bollworm populations were consistently high throughout the trial and egg deposition was consistent in all the plots with no significant differences. Three DAT, all the treated plots had significantly lower bollworm numbers than the untreated control (Table 1). Damaged fruit counts were not significantly different. Five days after treatment, none of the treated plots had significantly lower bollworm numbers than the untreated although a trend existed for lower numbers in the treated plots. Only the Tracer and F0570 were effective at lowering numbers below threshold levels. Treatment efficacy started to decline in all plots with only the F0570 providing 70% control. No significant differences were found between yields (Table 2). However, when yields are compared to average number of larvae per ten plants and average percent control, the trend favored higher yields with the more efficacious treatments. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Arthropod Management Tests Oxford University Press

EVALUATION OF NEW INSECTICIDES FOR CONTROL OF BOLLWORM IN COTTON, 2002

Arthropod Management Tests , Volume 29 (1) – Jan 1, 2004

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Publisher
Oxford University Press
Copyright
© Published by Oxford University Press.
eISSN
2155-9856
DOI
10.1093/amt/29.1.F58
Publisher site
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Abstract

(F58) COTTON: Gossypium hirsutum L.; 'Deltapine 436RR' 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: c-sansone@tamu.edu D. A. Mott Texas Cooperative Extension 3151 Innerloop, Ste. A Georgetown, TX 78626 Phone: (512) 943-3300 Fax: (512) 943-3301 E-mail: d-mott@tamu.edu Bollworm (BW): Helicoverpa zea (Boddie) Cotton was planted on 10 Apr into a Houston clay in 38-inch rows in central Tx near Taylor. The fertility and herbicide programs followed Extension recommendations for cotton in this region. Plot size was 75 ft x 4 rows with four replications in a RCB design. Insecticide applications were made on 28 Jun, at first bloom, with a self-propelled CO - pressurized sprayer calibrated to deliver 8.0 gpa at 30 psi with three TX-6 hollow cone nozzles per row. The adjuvant Kinetic (0.25% v/v) was added to the Denim treatment, and Steward was applied with Agri-Dex, a crop oil concentrate (0.5% v/v). The treatments were evaluated on 1 and 5 Jul. A random plant from one of the two center rows of the plot was selected, which served as a starting point to begin making counts. Ten consecutive plants were visually inspected for number of bollworm larvae and bollworm eggs from one of the center two rows of each plot. In addition, 25 squares were randomly pulled from the center two rows of each plot and all bollworm damaged fruit was counted and recorded. Yield was taken by harvesting 1/1000 acre from each of the middle two rows of each plot. All data were analyzed using ANOVA and LSD (P ≤ 0.05). Percent control was calculated using Henderson's formula. Bollworm populations were consistently high throughout the trial and egg deposition was consistent in all the plots with no significant differences. Three DAT, all the treated plots had significantly lower bollworm numbers than the untreated control (Table 1). Damaged fruit counts were not significantly different. Five days after treatment, none of the treated plots had significantly lower bollworm numbers than the untreated although a trend existed for lower numbers in the treated plots. Only the Tracer and F0570 were effective at lowering numbers below threshold levels. Treatment efficacy started to decline in all plots with only the F0570 providing 70% control. No significant differences were found between yields (Table 2). However, when yields are compared to average number of larvae per ten plants and average percent control, the trend favored higher yields with the more efficacious treatments.

Journal

Arthropod Management TestsOxford University Press

Published: Jan 1, 2004

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