Apple, Early Mite Control, 1976

Test materials were applied to 11-year-old apple trees at Monmouth, Maine, as dilute sprays with a hand gun from a hydraulic sprayer operating at 300 psi and at a rate of ca 500 gal per acre. Spray dates were April 23 (half-inch green). May 10 (pink), June 2-3 (petal fall), June 10 (first cover), and June 24 (second cover). The standard pesticide program consisted of captan 80W.(1.25 lb/100 gal) on 14 dates, Epsom salts (15 lb) and Marlate 50W (3 lb) on June 3, 11, and 24, and Sevin 80W (1.25 lb) on July 8 and 22. There were no tank-mixtures of acaricides with other pesticides. There were 4 single-tree replications per treatment. A randomized complete block design was utilized with 2 Cortland and 2 Early Mcintosh cultivars per treatment in Test 1, 4 Red Delicious per treatment in Test 2, and 2 Mcintosh and 2 Golden Delicious per treatment in Test 3. From each tree, 25 leaves were collected mostly at chest-height around the periphery of the tree, brought into the laboratory, and brushed onto glass plates coated with a Tween 20-alcohol mixture; mites were counted the same day. Mite population pressure was not very severe. Following hot and dry weather the first half of June, there was abundant rainfall through July.