Tufted Apple Bud Moth Control Tactics for Apple, 1997

Abstract

Abstract Experimental and registered treatments were applied to replicated 12 to 15 tree plots in a RCB design. Each plot consisted of alternating trees of ‘Yorking’, and ‘Golden Delicious’. These trees were planted to a spacing of 18 X 25 ft and were 18 years old. Experimental sprays were applied with a Friend Airmaster ‘309’ calibrated to deliver either 100 GPA at 2.4 mph or 50 GPA at 2.5 mph. All applications were made as complete sprays except for the second RH-2485 treatment and the Confirm treatments, which were applied as alternate row middle (ARM) applications. Spray timings were based on the accumulation of degree days from first sustained adult moth capture in a sex pheromone trap (13 May) in order to predict various percentages of egg hatch for each brood of TABM. TABM egg hatch data were generated from an adjacent block of apples where TABM egg hatch was monitored on a daily basis throughout the season. Degree day calculations were based on minimum and maximum developmental thresholds of 45°Fand91°F, respectively. Refer to the first table for a listing of treatments, gallonage, method and date of application, and degree day calculations. A routine schedule of fungicides (Benlate 50 DF, Penncozeb 75 DF, Rubigan 1 EC, and Ziram 76 WP) was maintained throughout the experiment. The effect of the sprays on WALH was evaluated by counting the number of nymphs/25 injured leaves/tree (cv. Yorking). Effectiveness of the test chemicals on the ERM, TSSM, and AF was evaluated by counting the mites several times during the season on samples of 25 random leaves/tree (cv. Yorking), 100 leaves/treatment. The cumulative number of mite day s per leaf was calculated for certain treatments from 17 Jun to 12 Aug. The effect of sprays on the predator SP was evaluated by 3-min counts of adults and larvae around the periphery of the same trees. STLM was evaluated by a 5-min count of tissue-feeding mines around the periphery of the trees at the end of each generation. On each sampling date, the total number of mines observed within 5 min regardless of their location on the tree were counted. The number of natural enemies of the spirea aphid were counted in a 5-min examination around the periphery of the center ‘Yorking’ tree. Shelters of the various leafrollers were counted in a 5-min examination of each plot tree on 22 Jul. All larvae were collected and returned to the laboratory for identification. Effectiveness of the treatments on fruit feeders on ‘Golden Delicious’ was assessed by scoring for injury a harvest sample of 100 fruit per tree from each of two center trees per replicate starting on 22 Sep and up to 25 dropped fruit per tree. For ‘Yorking’, injury was assessed on 200 picked fruit per tree from the 2 center trees in each replicate and up to 35 dropped apples per tree starting on 15 Oct. Pest pressure was moderate to heavy throughout the season.