Control of Japanese Beetle Adults on Rose, 1985

The container grown roses were trimmed 3 wk prior to spraying and fertilized to provide similar sized plants. Blossoms were trimmed as they opened throughout the test period. Four 3-plant replicates were arranged in a randomized complete block in a mowed field in Wooster, OH. Roses were sprayed on 16 Jul. Conventional treatments were applied with a hand-pumped, compressed air sprayer to the point of runoff. Sevin XLR+ “ULVA” was applied with an ultra-low volume applicator at 1 part XLR in 11 parts water to the point when a mist enveloped the plant. Treatments were evaluated by counting the number of beetles feeding on the plants (this provided an avg. no. per replicate from the 3 plants in the replicate) and by taking feeding injury ratings. The injury ratings were 0-10% damaged leaves = 0, 10-25% = 1, 25-40% = 2, 40-60% = 3, 60-75% = 4, 75-90% = 5, 90-100% = 6 (individual ratings were taken, then averaged for a single rating per replicate). Injury ratings were taken throughout the test period but only the final rating is shown. 1.19 inch rain occurred during the test period.