Apple, Chemical Control of Codling Moth, 1985

Abstract

Abstract Several insecticides were evaluated for their ability to provide seasonal control of codling moth. This test was conducted in a 15-year-old apple orchard with under-tree irrigation. The experimental design was a randomized block with 5 single-tree replicates per treatment. All materials were applied in a dilute spray to the point of drip (approximately 400 gal per acre) with a handgun sprayer operating at 400-500 psi. Two applications were made against first generation. IGR materials (first 5 listed) were applied at 75 degree days (9 May) after first moth was detected in pheromone traps. The second application was applied 21 days after the first (1 Jun). Guthion and Guthion-Dimilin combination were timed to coincide with predicted 3% egg hatch or 250 degree days following first moth (23 May). The second application was 21 days following the first (13 Jun). There was not a second application of the Guthion-Dimilin combination. One application was made against second generation, timed at 1000 and 1450 degree days after first moth for IGR’s and OP’s, respectively. Dimilin alone was applied against second generation in the plot which received the Guthion-Dimilin combination in first generation. All fruit on each tree were examined after first generation and at harvest. The number of damaged fruit from each tree was recorded. Codling moth adult activity was monitored using pheromone traps. Traps were examined weekly and numbers of moths recorded. Pheromones were changed every 4 wk, and trap bottoms were changed after an accumulation of 30 moths. Mites were sampled from mid-Jun through mid-Sep. Ten leaves were collected from each tree (total 50 leaves per treatment) and returned to the laboratory. Leaves were processed through a mite brushing machine and mites counted under a dissecting microscope. Mites densities are presented as mean mites per leaf for the growing season.