Apple, Insect and Mite Control, 1980

Abstract

Abstract Test materials were applied to apple trees at Monmouth (Test I) and Winthrop, Maine (Tests 2 and 3), as dilute sprays with a hand gun from a hydraulic sprayer operating at 200 psi at rates of 200 gal/A (Test I) and 300 gal/A (Tests 2 and 3). The trees were sprayed on May 17-20 (pink), May 31-Jun 2 (petal fall), Jun 17-18, Jul I, 13-15, 28-29, and Aug 13-14 (first cover through fifth cover); the cover spray on Jul 28-29 was repeated on Jul 31-Aug I because a 0.6 inch rain was recorded on Jul 29 and maggot fly activity was peaking. Materials were applied on dates as noted in table. In Test I the fungicide program (rates are per 100 gal) consisted of captan 80W (10 oz) plus Benlate 50W (3 oz) on 10 dates. In Tests 2 and 3 the fungicide program consisted of Phygon 50W (6 oz) plus Difolatan 4F (4 qt) on May I ( ca. half-inch green ), Phygon 50W (4 to 6 oz) on 2 dates, and Cyprex 65W (8 oz) at petal fall. In addition Polyram 80W (2 lb) was tank-mixed with each insecticide at each spray in all tests. There were 4 to 5 single-tree replications/treatment. A randomized complete block design was utilized with 2 “Mcintosh” and 2 “Spartan” cultivars/treatment in Test I; 4 “Mclntosh”/treatment in Test 2; and 2 “Cortland”, 2 “Red Delicious” and I “Mclntosh”/freatment in Test 3. Except for the test trees, these orchards were unsprayed. On Aug 28-29, three-fourths box of apples was picked from each tree and generally ca. 465-555 apples (Test I and 2) and 590-670 apples (Test 3) were examined per treatment on Sep 6 to 13 for external egg punctures (apple maggot), egg-laying scars (plum curculio), and typical feeding injuries (codling moth and lesser appleworm). Aphid counts are based on 10 randomly selected vegetative terminals around each tree. Numbers of live aphids found on the distal 4 unfurled and I furled leaves and on the stem included by these leaves were recorded on 2 dates from Aug 5 to 18. European red mites were counted on 2 dates from Aug 5 to 25 on 20 to 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. The heaviest population pressures were by the plum curculio and mites. Except for heavy rains on Jun 20, Jul 23, and 29, Jun, Jul, and Aug were hot and dry.