Insecticide Evaluation, 1993

Abstract

Abstract This experiment was conducted in a 5.4 acre block of 39-yr-old trees, which measured 16.5 ft. in height antl 23 ft. in width and were planted 20 × 40 ft. apart. The experimental design for the first 7 treatments and the check consisted of 6 single-tree plots (3 ‘Rome Beauty’, 3 ‘Golden Delicious’) in a randomized block design. The experimental design for treatments of S-71639 and Fenoxycarb consisted of 3 replications of 9-tree plots (3 rows × 3 trees/row) in a randomized block design, with insect data taken from the center tree (‘Rome Beauty’) in each plot. Insecticides were applied with a Swanson DA500A airblast sprayer which traveled at 2.4 mph. A spray volume of 300 gpa was used in the delayed dormant application of oil in the first treatment, with all other treatments applied at 100 gpa. Dates of application were 14 Apr (delayed dormant [DD]), 24 Apr (prepink [PP]), 14 May (petal fall [PFJ), 27 May (first cover [1C]), 14 Jun (second cover [2C]), 29 Jun (third cover [3C]), 15 Jul (fourth cover [4CD, 30 Jul (fifth cover [5C]), 12 Aug (sixth cover [6C]), 26 Aug (seventh cover [7C]), and 8 Sep (eighth cover [8C]). Other materials applied separately to all treatments were Bayleton, Captan, Dodine, Kocide, NAA, Nova, Streptomycin, Topsin-M, and Ziram. Control of SA was evaluated by counting aphids on the most infested leaf on each of 10 terminals from the periphery of each tree. Treatment effect against STLM was determined by counting mines observed on the periphery of trees during a 5 min period. Effect of treatments against RLH and WALH was determined by counting nymphs on 25 leaves selected from the tree periphery. ERM control was evaluated by sampling 25 leaves from the periphery of each tree, removing mites with a mitebrushing machine, and counting motile stages with a binocular microscope. Control of fruit-feeding insects was determined by scoring for injury 100 picked apples/replication plus up to 100 drop apples/replication on 22 Sep. Fruit picked (100/tree) from 3 replications of ‘Golden Delicious’ trees were rated for finish as 0 (no russet), 1 (enlarged and raised lenticels), 2 (1-10% russeted surface), 3 (11-25% russeted surface), 4 (26-50% russeted surface), or 5 (>50% russeted surface).