Apple, First Generation White Apple Leafhopper Control Test, 1986

An insect growth regulator compound was evaluated for control of first generation WALH nymphs. This test was conducted in a 4-year-old orchard with over-tree irrigation. A randomized complete block design was used, with 4 single-tree replicates per treatment. Materials were applied as a dilute spray to the point of drip with a handgun sprayer operating at 400-500 psi. Per acre rates were based on 400 gal/acre. Treatment timings were selected to coincide with petal fall (10 May), 75 degree days after codling moth biofix (16 May), and first appearance of fourth instar WALH nymphs (15 May). WALH densities were determined by counting nymphs on 20 randomly selected leaves showing leafhopper feeding injury from each tree (80 leaves per treatment). Posttreatment mite populations were assessed by collecting 20 randomly selected leaves from each tree (100 leaves per treatment), brushing them in a mite brushing machine, and counting mites of each species recovered.