Abstract Spring and summer applications of insecticides to golf course fairways were evaluated for efficacy in controlling white grubs. Treatments were applied in separate areas on 8 May and 8 Aug. Plots were 10 x 10 ft replicated 4 times in a completely random design. For each plot, liquid formulations of insecticides were applied by sprinkler can in 1 gal of water and irrigated after application with 2 gal of water. Granules were applied with a hand shaker made from a pint jar with a perforated lid. Some treatments were irrigated with 2 gal of water while others were not irrigated (see table). Thatch in the test areas ranged from 0 to 0.5 inch thick. Four locations in each plot were sampled with a cup-cutter (4.25 in. in diam) to a depth of 3 in. The predominate species of white grub in both trials was the Asiatic garden beetle comprising 91 to 97% of the population on all sample dates. Samples were collected at 4 and 6 or 19 weeks posttreatment and mean values for each sample date were compared by ANOVA. Accumulative precipitation during the trials was 3.39 and 17.37 inches at 4 and 19 weeks, respectively, for the spring application, and 2.52 and 2.63 at 4 and 6 weeks, respectively, for the summer application.