Sevin Evaluation, 1996

This experiment was conducted in a 0.8 acre block of 16-yr-old trees on MM 106 rootstock. Trees measured 13.5 ft. in height and 14.5 ft. in width and were planted at a spacing of 18 X 24 ft. The experimental design consisted of a single plot of 5 rows X 5 trees/row for each of 2 spray treatments and a single 10 row X 3 trees/row untreated plot. Insecticides were applied as complete sprays to both sides of the trees with a Swanson DA500A airblast sprayer, which traveled at 2.3 mph and delivered a spray volume of 100 gpa. Dates of application were 7 May [petal fall (PF)], 22 May [first cover (IC)], 11 Jun [second cover (2C)], 26 Jun [third cover (3C)], 11 Jul [fourth cover (4C)], 25 Jul [fifth cover (5C)], 7 Aug [sixth cover (6C)], 21 Aug [seventh cover (7C)], and 5 Sep [eighth cover (8C)]. Other materials applied separately to all treatments were Agri-Mycin, COCS, Dithane, Nova, Penncozeb, and Ziram. Treatment effect was determined by counting arthropod pests and injury on the periphery of 4 single-tree ‘Delicious’ replications in the center rows of each plot periodically during the season. Control of WALH was determined by counting nymphs on the underside of 25 leaves per tree. PLH was determined by counting injured terminals during a 5 minute period per tree. Effect of treatments against ERM was determined by sampling 25 leaves/tree, removing mites with a mite-brushing machine, and counting motile stages with a binocular microscope. Control of OFM was determined by counting injured terminals per tree. STLM control was evaluated by counting all tissue-feeding mines during a 5-minute period per tree.