Novartis Products Evaluation, 1997

Abstract

Abstract This experiment was conducted in a 2.4-acre block of 3-yr-old trees on EMLA, 26 rootstock (‘Rome’ and ‘Golden Delicious’) and Mark rootstock (‘York’). Trees measured 8 ft in height and 6.5 ft in width and were planted at a spacing of 12X18 ft. The experimental design consisted of a single plot of 12 rows (4 of each variety) X 10 trees/row for each of three spray treatments and an untreated plot. Insecticides were applied as complete sprays to both sides of the trees with a FMC Economist airblast sprayer, which traveled at 2.2 mph and delivered a spray volume of 200 gpa for the delayed dormant (½-inch green) application and 75 gpa for all other applications. Dates of application were 3 Apr [delayed dormant (DD)], 11 Apr [pink (P)], 16 May [petal fall (PF)], 28 May [first cover (IC)], 12 Jun [second cover (2C)], 24 Jun [third cover (3C)], 10 Jul [fourth cover (4C)], 25 Jul [fifth cover (5C)], 11 Aug [sixth cover (6C)], and 25 Aug [seventh cover (7C)]. Other materials applied in combination were Captan (treatments 1-3), Dithane (treatments 1-3), Nova (treatment 3), Vangard (treatments 1 and 2), and Ziram (treatments 1-3). Treatment effect was determined by counting arthropod pests and injury on 4 single-tree replications of ‘Rome’ and ‘York’ periodically during the season. Control of WALH was determined by counting nymphs on the underside of 25 leaves per tree. Control of SA was evaluated by counting aphids on the most infested leaf on each of 5 terminals per tree. Effect of treatments against ERM was determined by sampling 25 leaves per tree (York only), removing mites with a mite-brushing machine, and counting motile stages with a binocular microscope. Control of STLM was determined by counting all tissue-feeder mines during a 5-min period per tree. Control of fruit-feeding insects was determined by scoring for injury 100 picked apples per replication of ‘Golden Delicious’ on 17 Sep, and ‘Rome’ and ‘York’ on 25 Sep. ‘Golden Delicious’ fruit were also rated for russeting as 0 (no russet), 1 (raised lenticels), 2 (1-10% russeted surface), 3 (11-25% russeted surface), 4 (26-50% russeted surface), or (5>50% russeted surface).