Efficacy of Halofenozide (A Growth Regulator) and Merit Against European Chafer Larvae Relative to Dates of Application on a Home Lawn, 1996

Halofenozide (RH-0345) and Merit were applied on one of three application dates and tested for efficacy against European chafer larvae on a home lawn at the Suburban Experiment Station, Waltham, MA. The lawn consisted of 30% crabgrass (Digitaria sanguinalis), 30% perennial ryegrass, 20% Kentucky bluegrass, 20% dandelion (Taraxacum officinale L.), and was mowed at ca. 1.5 inches. Treatment plots were 8 ft by 8 ft, replicated 5 times, arranged in a CRB. Applications were made on 28 Jun, 23 Jul, or 20 Aug. All applications were liquid formulations and were applied by hand with a watering can using 3-4 liters of water per plot. Soil conditions at the study site at time of application were as follows: soil type, silty loam; soil pH 6.2. Plots were watered in with 3-4, 5, or 10-11 gal of irrigation through overhead irrigation immediately after application on 28 Jun, 23 Jul, and 20 Aug, respectively. Product efficacy was evaluated for all treatments on 26 Sep (90, 64, and 36 DAT respectively) by removing 5 cup-cutter plugs (4.25 inch diam) from near the center of each plot, dislodging soil and counting all grubs to a depth of 3 inches.