Evaluation of Spinosad, Bifenthrin, Chlorpyrifos, and Experimental Formulations for Management of Black Cutworm Larvae on Creeping Bentgrass, 1997

Abstract

Abstract Treatment plots were 6 X 8 ft, arranged in a RCB design and replicated 4 times. White PVC cylinders (8-inch diam X 6 inch length) were placed in each replicate and secured in place. One cylinder was placed in each replicate per evaluation period (15 Aug, 17 Aug, and 21 Aug). Ten 0.5- to 0.75-inch black cutworm larvae were placed in each cylinder on 12 Aug. Bird netting was placed over the experimental area from 13 Aug through 17 Aug to prevent bird predation. Liquid formulations were applied by using a CO2 compressed-air sprayer with 4 8002VS TeeJet nozzles mounted on a 6 ft boom, operating at 28 psi, and applied in 363 ml of water/48 ft2 or delivering 2.0 gal/1,000 ft2. At treatment time (14 Aug), the following soil and environmental conditions existed: air temperature, 72° F; soil temperature at 1 inch depth, 76° F; soil temperature at 2-inch depth, 70° F; RH, 69%; amount of thatch, 0.125 inch; soil textural class, sandy loam; soil particle size analysis: 59.7% sand, 30.5% silt, 9.8% clay; soil percent water weight (percent by weight), 19.9%; organic matter, 4.6%; water pH, 7.0; soil pH, 6.9; time of application, early morning; and clear skies. A total of 1.4 inches of rainfall or irrigation was recorded from 12 Aug through 14 Aug; a total of 0.8 inch of rainfall or irrigation was recorded from 14 Aug through 17 Aug; and 1.0 inch of rainfall or irrigation was recorded from 17 Aug through 18 Aug. The area was syringed on an as needed basis from 19 Aug through 21 Aug. Efficacy data was recorded on 15 Aug, 17 Aug, and 21 Aug by counting the number of black cutworm larvae flushed to the surface within each PVC cylinder by using a soap irritant drench.