Seasonal Airblast Insecticide Evaluation, 1989

Abstract

Abstract Experimental sprays were applied to 3 tree plots in a randomized block design consisting of 3 replicates of 'Yorking and 2 replicates of Golden Delicious'. Trees were spaced 20 × 30 ft and were 14-yr-old. Experimental sprays were applied with a Friend Airmaster '309' at 25 gal/acre per alternate side spray (50 gal/acre both sides) driven at 2 mph. Rates for treatments are listed as amt/acre/both sides spray. Spray dates for the alternate side treatments were: 25 Apr (Orthene only, complete spray); 18 and 25 May; 1, 8, 15, 22, and 29 Jun; 11, 18, and 26 Jul; 4, 10, 17, and 25 Aug; and 1 Sep. Penncap M plus Lannate 90 SP was substituted for the Danitol treatments on 1 Jun; 11, 18, and 26 Jul; 4, 10, 17, and 25 Aug; and 1 Sep. Apollo 50 SC was added to the second Danitol treatment on 22 and 29 Jun. Swat was added on 8, 15, and 22 Jun to various treatments. A routine schedule of fungicides (Nova 40 WP and Difhane M-45) was maintained throughout the experiment. Effectiveness on the aphid complex was evaluated by counting aphid-infested leaves on 10 terminals and aphids/most infested leaf. The effect of sprays on WALH was evaluated by counting nymphs on 25 leaves/tree. STLM was evaluated by a 5-min count of mines around the periphery of test trees. Effectiveness of test chemicals on ERM and ZM was evaluated by counting mites several times during the season on samples of 25 leaves/tree, 125 leaves/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 Jul and 2 picked samples on 15 Aug and 22 Sep. Apple samples averaged 181 fruits/replicate and 350/treatment. Pest pressure was heavy throughout the season. Russet ratings are based on 30 Golden Delicious apples/replicate, 60/treatment. Fruits were rated as 1 (no russeting), 2 (light russeting), 3 (moderate russeting), or 4 (severe russeting). Possible ranges were 30-60 (none to light), 60-90 (light to moderate); 90-120 (moderate to severe).