Apple, Full Season Insecticide Evaluations, 1987

Experimental insecticide treatments were applied in a comparative test to Red Yorking and Redspur Delicious trees. A randomized block design was used, and each treatment was replicated 4 times on each variety. Trees were sprayed to runoff using a Bean 35 gal/min hydraulic sprayer operating at 400 psi. ERM populations were evaluated on Yorks throughout the season. Due to a shortage of fruit on the Yorks, postbloom applications were included on Redspur Delicious. 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. RAA populations were evaluated on 28 May by counting all colonies found in 3 min/tree. Foliage was visually rated on a scale of 0 - 4 for WALH damage on 8 Sep. On 21 Sep 100 apples were collected from each replicate and evaluated for damage by fruit-feeding pests and for fruit finish on a scale from 1 to 5, 1 being the best.