Apple, Insect and Mite Control, 1984

Abstract

Abstract Test materials were applied to 28-year-old apple trees at Monmouth, Maine, as dilute sprays using a hand gun and a hydraulic sprayer operating at 250 psi at 300 gal/acre. Trees were sprayed on 17 May (pre-pink), 3 Jun (petal fall), 16 Jun (first cover), 27 Jun (second cover), 11 Jul (third cover), 26 Jul (fourth cover), 8 Aug (fifth cover), 20 Aug (sixth cover). Materials were applied on dates as noted in table. The fungicide 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. In addition, Polyram 80W (2 lb) was mixed with each insecticide treatment at each of the first 5 post-bloom sprays, and Captan 80W (1 lb) was mixed at the last 2 cover sprays. There were 4 single-tree replications for each treatment. A randomized complete block design was used, with 2 ‘Mcintosh’ and 2 ‘Cortland’ cultivars per treatment. Except for test trees, the orchard was not sprayed with insecticides. On 30 Aug, 0.5 box of apples was picked from each tree, and about 490 apples were examined per treatment on 9 to 15 Sep for external egg punctures (AM) egg-laying scars (PC), and typical feeding injuries (CM and LAW). ERM were counted on 3 dates from 19 Jul to 17 Aug 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. Aphid counts are based on 5 randomly selected vegetative terminals around each tree. Numbers of live aphids on the distal 4 unfurled and 1 furled leaves and on the stem included by these leaves were recorded on 9 and 17 Jul. Jul and Aug were relatively dry (1.8 and 1.5 inches rain, respectively); Aug was also warm.