Apple, Kelthane Applications, 1984

Test chemicals were applied to 28-year-old apple trees at Monmouth, Maine, as dilute sprays using an airblast sprayer operating at 200 psi and at 300 gal/acre. Spray dates were 22 May (pink), 4 Jun (petal fall), 13 Jun (first cover), and 6 and 13 Jul. The standard pesticide program consisted of Difolatan 4F (5 qt/100 gal) on 29 Apr, Phygon 50W (0.5 lb) on 1 Jun, Polyram 80W (2 lb) and Amid-Thin W (12 ppm) on 13 Jun, and Cyprex 65W (0.75 lb) on 29 Jun and 3 Jul. There were no mixtures of acaricides with other pesticides. Each treatment was applied to a block of 5 to 6 trees in which mite counts were made on 2 ‘McIntosh’ and 2 ‘Red Delicious’ cultivars in Test 1, and 2 ‘Cortland’ and 2 ‘Red Delicious’ cultivars in Test 2. From each tree 25 leaves were collected at chest-height 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. On days 3 to 5 following petal fall treatments, maximum daily temperatures ranged from 86°-95°F, and on day 3 following first cover treatments, minimum was 41°F. Maximum temperatures of 89°-90°F occurred on the 2 days after treatments on 13 Jul. The first half of Jun was warm and the last half was wetter than normal (3.0 inches rain); Jul and Aug were dry (1.8 and 1.5 inches rain, respectively).