Insect and Mite Control, 1988

Test materials were applied to 32-yr-old apple trees at Monmouth, Maine, as dilute sprays by handgun and hydraulic sprayer operating at 200-250 psi at 370 gal/acre. Trees were sprayed on 1 Jun (petal fall [PF]), 11 Jun (first cover [1C]), 27 Jun (second cover [2C]), 11 Jul (third cover [3C]), 25 Jul (fourth cover [4C]), 8 Aug (fifth cover [5C]), and 22 Aug (sixth cover [6C]). The standard pesticide program consisted of Manzate 200 80 W (0.8-1.5 lb/100 gal) on 5 dates, and Rubigan 1 EC (0.2 lb), Cyprex 65 W (0.4-0.8 lb), Unfoamer (0.1 lb), and Dithane M22 80 W (0.8-1.5 lb) on 2 dates. There were no mixtures of insecticides with other pesticides. There were 4 single-tree replications for each treatment. A randomized complete block design was used with 2 ‘McIntosh’ and 2 ‘Cortland’ cultivars. Except for the test trees, the orchard was not sprayed with insecticides or acaricides. On 30 Aug, about 485 apples were picked from the 4 trees of each treatment and examined 7-10 Sep for external egg punctures (AM), egg-laying scars (PC), and typical feeding injuries (CM and LAW). ERM and TSSM were counted on 25 leaves collected at chest-height from 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. June, July, and August were generally warmer and more humid than normal; the latter 2 months were relatively wet.