Apple, Dilute Test of Insecticides, 1985

Abstract

Abstract Experimental sprays were applied to run-off to single-tree plots in a randomized block design consisting of 2 replicates of Golden Delicious and 2 replicates of York Imperial. Treated single trees were separated by others not sprayed with insecticides. Sprays were applied with a John Bean sprayer, 35 gpm pump, equipped with a spray mast carrying spray guns arranged to wet the uniformly trimmed trees. Approximately 8.0 gal of spray were applied per replicate. Dates of application were: M0070616 treatments only—18 Apr, 8 and 22 May, 5 and 26 Jun, 17 Jul, 7 and 21 Aug; all other treatments—8 and 22 May, 5 and 19 Jun, 10 and 24 Jul, 7 and 21 Aug. Guthion 50WP (114 g/100 gal) was substituted for Brigade on 22 May, 19 Jun, 10 Jul, and 21 Aug. Brigade was increased to 91 g/100 gal on 5 Jun, 24 Jul, and 7 Aug. Pounce 3.2EC (30 ml/100 gal) was substituted for CME-13406 on 8 May. Guthion 50WP (114 g/100 gal) was substituted for CME-13406 on 19 Jun, 10 and 24 Jul; and for UC-SF-27 on 8 and 22 May. Kelthane 4F (473 ml/100 gal) was added to all M0070616 treatments except for the high rate of SDO 14114 on 26 Jun. Plictran 50WP (227 g/acre/half spray) was applied to all plots on 10 and 28 May. During the season general sprays involving Cyprex, Polyram, Benlate, Topsin M, Captan, Zineb, and calcium chloride were applied with an airblast sprayer at 50 gpa to the whole experimental block. Effectiveness on apple aphid was evaluated by counting aphid-infested leaves/10 top terminals, and aphids/most infested leaf. The effect of sprays on WALH was evaluated by counting nymphs/25 leaves/tree. Effectiveness of test chemicals on ERM, TSSM and predatory mites was evaluated by counting mites several times during the season on samples of 20 leaves/tree, 80 leaves/treatment. The effect of sprays on the predators S. punctum and H. vitripennis was evaluated by 3-min counts of adults and larvae and adults and nymphs, respectively, around the periphery of test trees. Effectiveness of chemicals on fruit feeders was assessed by scoring for injury all drops after 1 Jul and two picked samples on 14 Aug and 11 Sep. Apple samples averaged 123 fruits/replicate and 492/treatment. Pest pressure was heavy throughout the season. Russet ratings are based on 30 Golden Delicious apples/replicate, 120 treatment. Fruits are 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).