Rose Chafer, Bioassay to Determine Efficacy of Selected Adulticides, Ohio, 1978

Field efficacy was evaluated in a portion of a commercial vineyard at North Kingsville; laboratory bioassay was conducted at the OARDC in Wooster. Grape rows were 10 ft on center with 8 ft between vines in the row. A replicate consisted of 5 adjacent vines in a row. Each treatment was applied to 4 replicates in a randomized block design. Applications were made on June 14 and June 20. The first application was made soon after rose chafer adults were first observed feeding on grape blossom buds. Sprays were applied at the rate of 100 gpa with a CO2 powered constant pressure sprayer equipped with a Tee Jet® D2 disc and No. 25 core. Treated foliage was colleged after the spray residue was dry at 0, 3, and 7 days after treatment. Two leaves were picked at random from each replicate and placed in labelled plastic bags. The bags were placed in an ice chest and transported to Wooster. Approximately 4 hr later the petioles were recut and placed in a floral tube filled with water. Modeling clay was used to seal the top of the tube to prevent leakage. Ten beetles of unknown age and a floral tube containing 2 leaves were placed in a 1-gal ice-cream carton. The carton was modified by placing a 16-mesh wire screen over the bottom and cheese cloth over the top. Each bioassay included 4 replicates. The insecting holding room was maintained at 70°F with > 80% RH under a 16-hr photoperiod. The number of live beetles was recorded at the end of 24 hr.