Mite Control, 1991

Test chemicals were applied to apple trees at Monmouth, Maine, as dilute sprays by handgun and hydraulic sprayer operating at 250 psi. Treatments were applied at 375 or 150 gal/acre for test 1 (14-yr-old trees) and test 2 (6-yr-old trees), respectively. Spray dates were as indicated in table (petal fall was ca. 23 May). The standard pesticide program consisted of Nova 40 W (2.5 oz) on 5 dates, Captan 80 W (1.25 lb) on 5 dates, Pydrin 2.4 EC (2.7 oz) on 1 date, Sevin 80 S (1.25 lb) on 1 date, Ambush 25 W (3.2 oz) on 3 dates, Cyprex 65 W (6 oz) on 1 date in test 1 and Thiram 65 W (2.0 lb/100 gal) on 2 dates in test 2. There were no mixtures of acaricides with other pesticides. There were 4 single-tree replications for each treatment. A randomized complete block design was used, with 2 'Red Delicious' and 2 'Cortland' cultivars in test 1 and 1 each of 'Red Delicious,' 'Cortland,' 'Golden Delicious,' and 'McIntosh' in test 2. ERM were counted on 25 leaves collected at chest-height around the periphery of each tree. Leaves were brought into the laboratory and brushed onto glass plates coated with a Tween 20 and alcohol mixture; mites were counted the same day. Summer months were slightly warmer and more humid than normal, with less than, adequate rainfall in Jun and Jul.