Influence of Application Timing of Triumph 4 E and Oftanol 2 L on White Grub Control, 1991

Abstract

Abstract This study was conducted in Lincoln, NE, on a Kentucky bluegrass golf course rough. The predominant grass species was Kentucky bluegrass (95%) with a thatch accumulation (finger compressed) of 0.25 to 0.5 inch. Field conditions at the study site were: soil type, silty clay loam; soil organic matter, 3-5%; soil pH, 6.7; water pH, 7.0; soil moisture was maintained near field capacity throughout the study. Plots were 5 X 5 ft, and the experimental design was a randomized complete block with 4 replications. Liquid formulations were applied 17 Jun, 1, 15, 29 Jul, and 12 Aug, corresponding to 30 and 15 d before, at, and 15 and 30 d after the anticipated date of 99% completion of the SMC beetle flight period (15 Jul, based on light trapping records from the last four years). Subsequent light trap collections indicated that 99% beetle flight at the study site actually occurred on 11 Jul. Insecticides were applied with a C02 sprayer using an LF-4 nozzle at 24 psi and 5 gal/1000 ft2 spray volume. Immediately following applications the test area was irrigated with approximately 0.5 inch of water. A total of 6.75 inches of rain fell during the study period (6 Jun to 6 Sep). Product efficacy was evaluated 6 Sep by removing from each plot three, 8-inch diam turfsoil cores (1.0 ft2 total area) to a depth of 3 inches and counting the number of surviving grubs.