Apple, Timing of Second Generation Chemical Controls for Codling Moth, 1985

Abstract

Abstract A 7-year-old Red Delicious apple orchard was used to evaluate timing of an insect growth regulator (IGR) and an organophosphate insecticide (OP) for control of second generation codling moth. Each material was applied in a dilute spray to the point of drip (approximately 400 gal per acre) using a handgun sprayer operating at 400-500 psi. The IGR was applied at 900 (3 Jul), 1000 (8 Jul), 1100 (11 Jul) and 1200 (15 Jul) degree days after first codling moth catch of first generation. The OP was applied at 1250 (16 Jul), 1400 (22 Jul) and 1600 (29 Jul) degree days after first moth. The experimental design was a randomized complete block with 4 single-tree replicates per treatment. No chemical treatments were applied to the test orchard , (during the first codling moth generation. Inspection of fruit during thinning in late Jun indicated that a low level uniform infestation had been established throughout the test orchard. Following second generation all fruit were removed from test trees, counted and injured fruit collected and returned to the laboratory. Injured fruit were examined and cut with a knife to determine the number of shallow or deep entries. Live larvae found within fruit were saved and head capsules measured to determine their instar. Codling moth adult activity was monitored using pheromone traps. Traps were examined weekly and the number 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. Twelve or 13 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 were counted under a dissecting microscope. Mite densities are presented as mean mites per leaf for the growing season.