Spring Application of Conventional and Biorational Insecticides for Control of Sod Webworms, 1996

Abstract

Abstract Insecticides were evaluated for control of sod webworm larvae on a Kentucky bluegrass lawn at the Gering Cemetery, in Scotts Bluff County, Nebraska. The turf (80% Kentucky bluegrass, 20% perennial rye and tall fescue) was maintained at a mowing height of 2.5 inches. Thatch accumulation (finger compressed) in the plot area was 0.5 inch. Field conditions at the study site were: soil type, silt loam; soil organic matter, 2.3%; soil pH, 8.4. Weather conditions at the time of treatment were as follows: soil moisture 16% by wt; air temperature 70°F; soil temperature 62°F; relative humidity 29%; wind direction and velocity 157° at 11 mph. Plots were 7 x 7 ft and the experimental design was a RCB with 3 replications. Treatments were applied on 6 May. Liquid insecticides were applied using a CO, sprayer with a TeeJet® 8002 nozzle at 30 psi and delivering 2 gal finished spray/1000 ft2. Following applications, plots were irrigated with 0.125 inches of water. A total of 0.67 inch of rain fell during the post-treatment period. Treatments were evaluated 3,7, and 14 DAT (10, 14, and 21 May) by mixing 0.5 oz of Lemon Dawn® per gal of water and applying one gal of the dilution to each of two 6 ft sampling areas per plot (12.0 ft2 total area). Larvae that moved to the grass surface after twenty minutes, were collected and counted.