Apple, Concentrate Airblast Insecticide Test, 1983

Sprays were applied to single-tree plots in a randomized block design consisting of three replicates of ‘York Imperial’ and two replicates of ‘Golden Delicious.’ Treatments were applied with a Friend Airmaster 393 sprayer at 25 gal/acre per alternate side spray driven at 2 mph. Rates for treatments are listed as amounts per acre per both sides spray. Spray dates for treatments were: 18 and 25 May; 3, 10, 17, and 27 Jun.; 7, 15, and 25 Jul.; 3, 12, 19, and 26 Aug; and 2 Sept. Fungicides applied during the season were: Cyprex, Topsin M, Polyram, Rubigan, captan, zineb, and calcium chloride. Average temperatures were: May 57°F, Jun. 68°F, Jul. 75°F, Aug. 72°F, and Sept. 65°F. Rainfall in inches totaled: May 4.98, Jun. 4.42, Jul. 0.83, Aug. 2.01, and Sept. 2.05. Effectiveness on apple aphid was evaluated by counting aphid infested leaves per 10 top terminals, and aphids per most infested leaf per infested terminal. The effect of sprays on WALH was evaluated by counting nymphs per 25 leaves per tree. Effectiveness of test chemicals on ERM was evaluated by counting mites several times during the season on samples of 15 leaves per tree, 75 leaves per treatment. The effect of sprays on S.punctum was evaluated by 3-min counts of adults and larvae around the periphery of test trees. Effectiveness of chemicals on fruit feeders was assessed by scoring for injury all drops after 1 July and two pick samples on 15 Aug. and 16 Sept. Apple samples averaged 236 fruits per replicate and 1178/treatment. Pest pressure was moderate throughout the season.