Abstract
Abstract Sprays were applied to single-tree plots in a randomized block design consisting of 2 replicates of York Imperial and 3 replicates of Golden Delicious. Treatments were applied with a Friend Airmaster 393 sprayer at 25 gpa/alternate side spray driven at 2 mph. Rates of chemicals are listed as amounts/acre/alternate middle. Spray dates for the treatments were: May 16, 22, and 30, Jun 6, 17, and 25; Jul 2, 10, 18 and 28; Aug 5, 14 , 22 and 29. The Pounce 3.2EC treatment and Pounce plus Penncap M treatment were applied on the first 4 spray dates, whereas the 2 rates of FMC-45806 were applied on the remaining spray dates. Fungicides applied during the season were: Cyprex, Polyram, sulfur, capfan, zineb and calcium chloride. Average temperatures were: May 61.5°F, Jun 66.4°F, Jul 74.9°F, Aug 76.3°F and Sep 65.5°F. Rainfall in inches averaged: May 4.49, Jun 4.02, Jul 1.48, Aug 1.71 and Sep 1.53. Effectiveness on the apple aphid was evaluated by counting the number of infested terminals/10 top terminals/ tree, the number of aphid infested leaves/terminal, and the number of aphids/most infested leaf/infested terminal. The effect of the sprays on the white apple leafhopper was evaluated by counting the number of nymphs/25 Ivs/tree. Effectiveness of the test chemicals on the European red mite was evaluated by counting the mites several times during the season on samples of 15 leaves/tree, 75 leaves/treatment. The effect of sprays on the predators, S.punctum and H.vitripennis was evaluated by 3-minute counts of adults and larvae and adults and nymphs, respectively, around the periphery of the test trees. Effectiveness of chemicals on fruit feeders was assessed by scoring for injury all drops after Jul 17 and 2 picked samples on Aug 9 and Sep 15. Apple samples averaged 189 fruits/replicate and 946/treatmenf. Pest pressure was moderate throughout the season. Russet ratings are based on 30 Golden Delicious/replicate, 90/treatment. Fruits were rated as follows: no russet (1), light russet (2), moderate russet (3), and severe russet (4). Possible means are: no russet to light russet 30-60, light to moderate russet 60-90, and moderate to severe russet 90-120.
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