Effect of Rate and Timing of Biorational Materials for Control of Second Generation White Apple Leafhopper Nymphs, 1995
Abstract The test was conducted in a mature apple orchard (several strains of ‘Delicious’) at the Tree Fruit Research & Extension Center, Wenatchee, WA. Treatments were replicated 4 times, with each replicate consisting of a single tree. The experimental design was a RCB, using pre-treatment WALH populations as the blocking factor. The experimental treatments (three types of horticultural mineral oil and Neemix, a neem product) were applied at various rates and timings. The timings were selected based on previous experience of WALH phenology. The late Jul timing (27 Jul) coincides with the appearance of the 4th instars, while the mid-Aug timing (14 Aug) coincides with the first appearance of adults of the second generation. Pesticides were applied with a handgun sprayer to the point of drip. WALH populations were sampled ca. weekly by counting in situ all live nymphs on 20 leaves per tree, distributed throughout the tree canopy.