Apple, Insect and Mite Control, 1978

Abstract

Abstract Test materials were applied to apple trees at Monmouth (Test 1) and Winthrop, Maine, (Tests 2 and 3) as dilute sprays with a hand gun from a hydraulic sprayer operating at 300 psi and at 250-350 gal/acre. In Test 1, the trees were sprayed on May 31 (petal fall), June 7, 16, 29, July 12, 26, August 8, and 21 (first cover through seventh cover). Each material was applied on all dates. The fungicide program (formulations are rates/100 gal) consisted of Polyram 80W 1 lb and Benlate 50W 2 oz at 11 dates; Solubar .5 lb on May 16; Omite 6EC 4 oz on May 23, 31, and June 6; Epsom salts 15 lb on June 6 and 20; and Amid-Thin 8.4W .25 lb on June 13. In addition, Polyram 80W 2 lb was tank-mixed with each insecticide at each spray. In Tests 2 and 3, trees were sprayed on June 1 (petal fall), 9, 21, July 6, 19, August 2, and 15-16 (first cover through sixth cover). Each material was applied on alldates. The fungiside program (rates/100 gal) consisted of Difolatan 4F 4 qt at half-inch green and Polyram 80W 2 lb at each cover; Polyram was tank-mixed with each treatment. There were 4 to 5 single-tree replications per treatment. A randomized, complete-block design was utilized with 2 Mcintosh and 2 Spartan cultivars per treatment in Test 1; 4 Mcintosh per treatment in Test 2; and 2 Melba, 2 Cortland, and 1 Red Delicious per treatment in Test 3. Except for the test trees, these orchards were unsprayed. On August 29-30, three-fourths box of apples was picked from each tree and generally ca. 430 to 520 apples were examined per treatment on September 5-16 for external egg punctures (apple maggot), egg-laying scars (plum curculio), and typical feeding injuries (codling moth and lesser appleworm). Apple 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). Aphid and leafhopper counts were based on 10 randomly selected vegetative terminals around each tree. All live aphids found on July 17 and 24 (also August 11 for Test 3) on the distal 4 unfurled and 1 furled leaves and on the stem included by these leaves were recorded. Leafhopper evaluation was based on speckling feeding spots found on August 24-25 on the fifth and seventh leaves. European red mites were counted on July 24-28 and August 7-10 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. No pest population exerted very serious pressure in these tests. July and August were unusually hot and dry.