Apple, Insect and Mite Control,1982

Test chemicals were applied to 12 to 16-yr-old apple trees at Monmouth, Maine, as dilute sprays using a hand gun and a hydraulic sprayer operating at 100 lbs/in at 300 to 350 gal/ acre. Trees were sprayed on 19 May (pink), 3 or 4 June (petal fall), 14 or 15 June (first cover), 28 or 30 June (second cover), 12 or 13 July (third cover), 26 or 27 July, (fourth cover), 3 or 5 Aug. (fifth cover), and 16 or 17 Aug. (sixth cover); the cover spray on 26 or 27 July was repeated between 3 and 5 Aug. because 1.4 in of rain was recorded on 28 July. Materials were applied on dates as noted in table. The fungicide program consisted of Captan 80W (1 lb) mixed with each insecticide treatment at each spray. There were two to three single-tree replications in Test 1, and four in Test 2. A randomized complete block design was used, with ‘Mcintosh’ cultivars in Test 1, and three ‘Mcintosh’ and one ‘Spartan’ cultivar per treatment in Test 2. Except for test trees, orchards were unsprayed. On 25 and 26 Aug., 0.5 to 0.75 box of apples was picked from each tree and from about 140 to 290 apples (Test 1) and 450 to 480 apples (Test 2) were examined per treatment on 11 Sept. for external egg punctures (apple maggot), egg-laying scars (plum curculio), and typical feeding injuries (codling moth and lesser appleworm). European red mites were counted on three or four dates from 12 July to 17 Aug. on 25 leaves, collected mostly at chest-height around the periphery of each tree. The leaves were brought into the laboratory and brushed onto glass plates coated with a Tween 20/alcohol mixture; mites were counted the same day.