Miticide Evaluations, 1988

Treatments were applied to mature trees using single-tree plots arranged in a randomized block design and replicated 4 times. Trees were sprayed to run-off using a Bean 35 gal/min hydraulic sprayer operating at 300 psi. Morestan 25 W was applied at pink stage of bud development (15 Apr), and other treatments were applied on 29 Jun when average mite counts were 3.83/leaf. Mites and eggs were counted by randomly selecting 25 leaves/replicate, brushing onto glass plates with a modified Henderson-McBurnie brushing machine, and counting all motile forms and viable eggs with a binocular microscope. Due to the slow buildup of mite populations in this block, trees were seeded on 3 Jun by taping mite-infested shoots from several locations into each tree. Mite predators were kept at low levels during the early season with sprays of Asana, Sevin, and Lannate.