Apple, Codling Moth Control with Bacillus Thuringiensis, 1991

Several insecticides were evaluated for control of CM when used in a seasonal spray program. The test orchard was located at the Tree Fruit Research and Extension Center, Wenatchee. Test trees were 17-year-old non-spur ‘Red Delicious’. The orchard was irrigated by under-tree sprinklers on a 14-day schedule. The test design consisted of 4 single-tree replicates in randomized complete blocks. Treatments were applied with a handgun sprayer at 300 psi to the point of drip, simulating a dilute spray of approximately 400 gal/acre. In all cases the first treatment was applied at the beginning of the egg hatch, 28 May, 250 degree days following first capture of moths in a pheromone trap. The number of sprays applied for each CM generation depended on the chemical and rates used and are shown in the table. After the first CM generation (16 Jul), 100 fruit from each replicate were examined and the number damaged by CM recorded. At harvest (29 Aug), 200 fruit were picked from each replicate and examined for damage by CM and PLR. CM damage was rated as a “sting” (an unsuccessful entry in the fruit denoted by a scar but no penetration) or a deep entry. Mites were sampled in Jul, Aug and Sep. Twenty-five leaves were collected from each tree. In the laboratory leaves were processed through a mite brushing machine and each mite species was counted with aid of a dissecting microscope.