Insecticide Evaluation, 1994

Abstract

Abstract This experiment was conducted in 3 miniblocks, each Vs acre, of 16-yr-old trees on MM 111 rootstock. Trees measured 14.5 ft in height and 13 ft in width and were planted at a spacing of 20 × 20 ft. The experimental design consisted of six single-tree replicates per treatment, with two replications per mini-block using a randomized block design. Each replicate was surrounded by one unsprayed tree on each side. Insecticides were applied as complete sprays to both sides of the tree with a Swanson DA500A airblast sprayer, which traveled at 2.3 mph and delivered a spray volume of 100 gpa. Insecticide rates were based on tree row volume, resulting in the application of 72% of rates that would be used on standard size trees. Dates of application were 15 Apr (delayed dormant [DD]), 19 Apr (prepink [PP]), 6 May (petal fall [PF]), 24 May (first cover [1C1), 9 Jun (second cover [2C]), 23 Jun (third cover [3C]), 7 Jul (fourth cover [4C]), 21 Jul (fifth cover [5C]), 4 Aug (sixth cover [6C]), 18 Aug (seventh cover [7C]), and 1 Sep (eighth cover [8C]). Other materials applied separately to all treatments during this experiment were Captan, Kocide, Nova, Penncozeb, Rubigan, Streptomycin, Topsin-M, and Ziram. Treatment effect was determined by counting insects observed on the periphery of test trees periodically during the season. Control of RAA was evaluated by counting colonies per tree. SA control was determined by counting aphids on the most infested leaf on each of five terminals per tree. Effect of treatments against RLH and WALH was determined by counting nymphs on the underside of 25 leaves per tree. Treatment effect against STLM was evaluated by counting tissue-feeding mines observed during a 5 min period.