Effect of Date of Application on Efficacy of Dursban and Oftanol Against Annual Bluegrass Weevils, Golf Course Fairway, 1992:

Treatments were applied on 28 Apr or 12 May or on both dates to 2.6 x 2.3 m plots, which were replicated 5 times in a RCB design. The plots were established on a golf course fairway in Scarborough, NY-annual bluegrass (60%), creeping bentgrass (40%), maintained at 1.3 cm. All materials were applied with watering cans, using 3 liters water per plot. The entire test area received 0.3 cm irrigation 1 h after application. Soil pH was 6.2, water pH varied from 7.0 to 7.4. Product efficacy was evaluated on 11 Jun by removing 5 soil cores (10.6 cm diam) per plot and inspecting the cores under magnification in the Amherst laboratory (each plug was ca 0.01 m2). At the time of sampling, the population was 8% 3rd instar, 19% 4th instar, 63% 5th instar,and 10% pupae.