Apple, Pest Control with Igrs, 1987

Timing and rates of 2 IGRs were evaluated for control of major apple pests and effect on phytophagous and phytoseiid mites. Sprays were applied by handgun operating at 200 psi to 20-yr-old apple trees. Treatments consisted of 4 single-tree replicates (2 trees of each variety) in a randomized block. Fungicides (Cyprex, Bayleton) were applied when necessary. Guthion cover sprays were timed according to codling moth development (see Washington State University Extension Bulletin 1072). The IGRs were applied from 150 to 250 DD earlier than Guthion to coincide with the beginning and peak of egg laying. At mid-season (8 Jul) and at harvest (8 Oct), 100 fruit/treatment (25/tree) were inspected for insect damage. In addition, leaves were sampled twice during the season to evaluate mite populations and at harvest to evaluate WTLM and WALH (100 leaves/treatment; 25/ tree).