Insecticide Evaluation, 1992

We conducted this experiment in a 5.4 acre block of 38-yr-old trees, which measured 16.5 ft in height and 23 ft in width and were planted 20 X 40 ft apart. Experimental design consisted of 6 single-tree plots (3 ‘Rome Beauty,’ 3 ‘Golden Delicious’) in a randomized block design. Insecticides were applied with a Swanson DA500A airblast sprayer, which traveled at 2.4 mph and delivered a volume of 100 gal/acre. Applications were made on 9 Apr (delayed dormant [DD]), 22 Apr (prepink [PP]), 14 May (petal fall [PF]), 28 May (first cover [1C]), 11 Jun (second cover [2C]), 25 Jun (third cover [3C]), 9 Jul (fourth cover [4C]), 22 Jul (fifth cover [5C]), 7 Aug (sixth cover [6C]), 20 Aug (seventh cover [7C]), and 2 Sep (eighth cover [8C]). An application error was made at DD resulting in a 1.3 to 8 fold overdose. Other materials applied separately to all treatments were Bayleton, Captan, Dodine, Kocide, NAA, Nova, Solubor, Streptomycin, and Topsin-M. Control of RAA was evaluated by counting colonies/tree.