Apple Insect and Mite Control, 1976

Test materials were applied to apple trees as dilute sprays with a hand gun from a hydraulic sprayer operating at 300 psi and at a rate of ca 250 gal per acre in Test 1 and 350 gal per acre in Tests 2 and 3. The trees in Test 1 at Monmouth, Maine, were sprayed on May 25 (petal fall), June 3, 17, July 2, 14, 29, and August 13; and the trees in Tests 2 and 3 at Winthrop, Maine, were treated on May 30 (petal fall), June 5, 2 1 , July 6, 19, August 2 and 16. Each material was applied on all dates except as noted in Tables. The fungicide program consisted of Difolatan 4F (4 qt/100 gal) at half-inch green and Polyram 80W (2 lb/100 gal) at each cover; Polyram was tank-mixed with each treatment. There were 4 single-tree replications per treatment. A randomized complete block design was utilized with 4 Mcintosh cultivars per treatment in Tests 1 and 3 and 1 Red Delicious, 2 Cortland, and 1 Mcintosh per treatment in Test 2. Except for the test trees, these orchards were unsprayed. On August 30, 3/4 box of apples was picked from each tree and ca 500-600 apples were examined per treatment on August 30-September 11 for external egg punctures (apple magot), egg-laying scars (plum curculio), and typical feeding injuries (codling moth and lesser appleworm). Apples with maggot egg punctures were sliced to determine success of egg hatch and/or of maggot survival (success indicated by a larval penetration of more than 1/4 inch). European red mites were counted on 25 leaves per tree 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. Except for apple maggot and plum curculio, no pest population exerted serious pressure. July and early August were unusually wet.