Mite Control, 1989

Test chemicals were applied to 12-yr-old apple trees at Monmouth, Maine, as dilute sprays by handgun and hydraulic sprayer operating at 250 psi and at 350-440 gal/acre, for Tests 1 and 2, respectively. Spray dates were 18 Jun and 24 Jul, for Tests 1 and 2, respectively. The standard pesticide program consisted of Manzate 200 80 W (0.8-1.5 lb/100 gal) on 5 dates, Nova 40 W (1.5-2.0 oz), Sevin 80 S (0.7-1.2 lb), Captan 80 W (1.2 lb) on 4 dates, and Ambush 25 W (3 oz) on 1 date. 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 each test. 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. Early Jun was very wet, but late Jun and all of Jul were very dry. Summer temperatures were normal.