Insecticide Evaluation, 1988

Insecticides were applied to 6 single-tree plots (3 ‘Rome Beauty,’ 3 ‘Golden Delicious’) of 34-yr-old trees in a randomized block design. Applications were made with a Swanson DA500A airblast sprayer, which traveled at 2.4 mph and delivered a spray volume of 100 gal/acre. Dates of application were 6 Apr (delayed dormant [DD]), 12 Apr (prepink [PP]), 12 May (petal fall [PF]), 26 May (first cover [1C]), 14 Jun (second cover [2C]), 24 Jun (third cover [3C]), 11 Jul (fourth cover [4C]), 29 Jul (fifth cover [5C]), 11 Aug (sixth cover [6C]), 22 Aug (seventh cover [7C]) and 2 Sep (eighth cover [8C]). Other materials applied separately to all treatments were Bayleton, Benlate, Dithane M-45, Manzate 200, NAA, Solubor, Streptomycin, and Topsin-M. Control of AA and SA was evaluated by counting infested leaves on each of 10 terminals and the number of aphids on the most infested leaf/terminal on each ‘Golden Delicious’ tree. The effect of treatments on ERM was determined by sampling 33 leaves from the periphery of each ‘Rome Beauty’ tree, removing mites with a mite-brushing machine, and counting active stages with a binocular microscope. WALH control was evaluated by counting nymphs found on 25 leaves selected from the periphery of each tree. The effect of treatments on fruit-feeding insects was determined by scoring for injury 600 apples/treatment (100/replication) plus all fallen apples sampled on 20 and 21 Sep. Fruit picked from ‘Golden Delicious’ trees were rated for finish on a scale of 1-5, 5 being worst.