Abstract This experiment was conducted in a one third acre block of 8-yr-old ‘Redchief’ trees on M26, which measured 13.5 ft. in height and 9 ft. in width and were planted 10 × 15 ft. apart. The experimental design consisted of 4 single-tree plots in a randomized block design, with each replicate surrounded by at least one unsprayed tree on each side. Acaricides were applied with an FMC Economist airblast sprayer at 2.2 mph applying 100 gpa. Dates of application were 24 Jun, 14 and 29 Jul. Other materials applied separately to all treatments during the experiment were Captan, Guthion, Penncap-M and Topsin-M. ERM control was evaluated by sampling 25 leaves from the periphery of each tree, removing mites with a mite-brushing machine, and counting motile stages with a binocular microscope.