Efficacy of Three Insecticides Against European Chafer Larvae, Home Lawn, 1992

The lawn consisted primarily of Kentucky bluegrass (30%), annual bluegrass (25%), perennial ryegrass (25%), and assorted broad-leaved weeds (20%), maintained at 3.5 to 4.5 cm. Treatment plots were 2.6 x 2.6 m, replicated 5 times, arranged in a RCB design. All applications were made 11 Aug. Liquid formulations were applied by hand with watering cans, 3 liters water per plot. Granular formulations were applied using glass jars with perforated lids. Conditions at the time of application were as follows–air temperature 28°C; high overcast with moderate humidity; soil type, silty loam; soil pH 6.2; water pH, 5.6. All plots were watered in with ca. 0.6 cm irrigation immediately after application. There was an additional 0.6 cm of rainfall ca. 6 h after application. Product efficacy was evaluated 25 Sep (46 DAT) by cutting two 0.1 m2 samples out of each plot, dislodging soil with a hand trowel, and counting all grubs to a depth of 10 cm.