Spring Management of Bluegrass Billbug with Merit 75Wsp and Vector Tl at the Valentine Turfgrass Research Center, University Park, Pa, 1994

The field plot consisted primarily of Kentucky bluegrass. Treatment plots were 6 × 9 ft, arranged in a RCB design, replicated 4 times. Two ft untreated barriers were placed between each treatment replicate. Liquid formulations were applied by using a CO2 compressed air sprayer with 4 8004VS TeeJet nozzles mounted on a 6 ft boom, operating at 28 psi, and delivering 5 gal/1000 ft2. At treatment time (31 May), the following soil and environmental conditions existed: air temperature, 78°F; soil temperature at 1 inch depth, 76°F; soil temperature at 2 inch depth, 66°F; RH, 80%; amount of thatch, 0.25-0.5 inches; soil type, silt-clay-loam; soil particle size analysis: 16.0% sand, 54.2% silt, 29.8% clay; organic matter, 5.0%; soil moisture (oven baked), 14.7%; water pH, 6-7; soil pH, 6.9; and skies were clear. Immediately after treatment the experimental area was irrigated with 0.25 inches of water. Posttreatment counts were made 30 DAT (30 Jun). Bluegrass billbug control was evaluated by removing four 0.087 ft2 sod samples from each replicate, and the total number of bluegrass billbug life stages (larva, pupa, adult) were recorded from each sample and converted to a ft2 count. Sod samples were removed with a 4-inch cup cutter. Billbug feeding damage rating was recorded on 12 Jul. Each 54 ft2 replicate was rated by determining larval feeding damage based on color ratings.\