Insecticide Evaluation I, 1997

Abstract

Abstract This experiment was conducted in 3 miniblocks, each ⅓ acre, of 19-yr-old trees on MM.lll rootstock. Trees measured 15 ft in height and 14 ft in width and were planted at a spacing of 20 X 20 ft. The experimental design consisted of 6 single-tree replica tions per treatment, with 2 replications per mini-block in a randomized block design. Each replicate was surrounded by 1 unsprayed tree on each side. Insecticides were applied as complete sprays to both sides of the trees with a Swanson DA5OOA airblast sprayer, which traveled at 2.4 mph and delivered a spray volume of 100 gpa. Dates of application were 4 Apr [delayed dormant (DD)], 10 Apr [pink (P)], 12 May [petal fall (PF)], 21 May [10-20 mm fruit diameter], 27 May [first cover (lC)], 11 Jun [second cover (2c)], 24 Jun [third cover (3C)], 8 Jul [fourth cover (4C)], 22 Jul [fifth cover (5C)], 5 Aug [sixth cover (6C)], 19 Aug [seventh cover (7C)], and 2 Sep [eighth cover (8C)I. Other materials applied separately to all treatments were Agri-Mycin, COCS, Dithane, Nova, Penncozeb, Topsin-M, and Ziram. Treatment effect was determined by counting arthropods on test trees periodically during the season. RAA control was determined by counting colonies per tree. Control of WALH was determined by counting nymphs on the underside of 25 leaves per tree. Effect of treatments on STLM was determined by counting all tissue-feeder mines during a 5 minute period per tree. Control of SA was evaluated by counting aphids on the most infested leaf on each of 10 terminals per tree. Effect of treatments on MAL was determined by counting adults and larvae on 10 terminals per tree. Treatment effect against ERM and ARM was determined by sampling 25 leaves per tree (4 replications), 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 and up to 100 drop apples per replication on 23 Sep.