Insecticide Evaluation, 1995

Abstract

Abstract This experiment was conducted in 3 miniblocks, each ⅓ acre, of 17-yr-old trees on MM 111 rootstock. Trees measured 15 ft. in height and 14 ft. in width and were planted at a spacing of 20 X 20 ft. The experimental design consisted of 6 single-tree replications per treatment per treatment, with 2 replications per mini-block in a randomized block design. Each replicate was surrrounded by 1 unsprayed tree on each side. Insecticides were applied as complete sprays to both sides of the tree with a Swanson DA5OOA airblast sprayer, which traveled at 2.3 mph and delivered a spray volume of 100 gpa. Dates of application were 11 Apr [delayed dormant (DD)], 18 Apr [prepink (PP)], 20 May [petal fall (PF)], 1 Jun [first cover (lC)], 13 Jun [second cover (2C)], 30 Jun [third cover (3C)I for all treatments except (Product X), 6 Jul [third cover (3c)] (Product X) only, 13 Jul [fourth cover (4C)], 27 Jul [fifth cover (5C)], 14 Aug [sixth cover (6C)], 24 Aug [seventh cover (7C)], and 6 Sep [eighth cover (8C)l. Other materials applied separately to all treatments were AgriMycin, Dithane, Kocide, K-salt (NAA), Nova, Penncozeb, Rubigan, Topsin-M, and Ziram. Treatment effect was determined by counting insects observed on the periphery of test trees periodically during the season. Control of SA was evaluated by counting aphids on the most infested leaf on each of 10 terminalsltree. Effect of treatment against ERM was determined by sampling 25 leavesltree (4 replications), removing mites with a mite-brushing machine, and counting motile stages with a binocular microscope. WALH and RLH control was evaluated by counting nymphs on the underside of 25 leavesltree. Treatment effect against STLM was determined by counting tissue-feeding mines observed during a 5-min. periodltree. Control of fruit-feeding insects was determined by scoring for injury 100 picked appleslreplication plus up to 100 drop appleslreplication on 21 Sep.