Mite Control, 1988

Abstract

Abstract Test chemicals were applied to 11-yr-old apple trees at Monmouth, Maine, as dilute sprays by handgun and hydraulic sprayer operating at 200-250 psi and at 330-350 gal/acre. Spray dates were 21 May (pink-full pink [P-FP]), 1 Jun (petal fall [PF]), 11 Jun (first cover [1C]), 28 Jun (second cover [2C]), and 8 Jul (third cover [3C]). The standard pesticide program consisted of Manzate 200 80 W (1.5 lb/100) and Sevin 80 SP (0.7-1.2 lb) on 4 dates; Captan 80 W (1 lb) and Rubigan 1 EC (0.2 lb) on 3 dates; Cyprex 65 W (0.4-0.8 lb), Ambush 25 W (0.8 lb), and Unfoamer (0.1 lb) on 2 dates; and Imidan 50 W (1.5 lb) and Fruitone 3.5 W (5 ppm) 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. From each tree, 25 leaves were collected at chest-height from around the periphery of the tree, brought into the laboratory, and brushed onto glass plates coated with a Tween 20 and alcohol mixture; mites were counted the same day. June, July, and August were generally warmer and more humid than normal; the latter 2 months were relatively wet.