Apple, Early-Season Insect Experiment, 1994

Abstract

Abstract The experimental design was a randomized complete block, with five insecticide treatments and a control replicated four times. Plots consisted of two trees, one tree each of the cultivars ‘Yorking’ and ‘Golden Delicious’. The trees were planted at a spacing of 20 × 20 ft and were 21 years old. Experimental sprays were applied with a Myers Mity Mist airblast sprayer calibrated to deliver 100 gpa. The Lorsban and Asana treatments were applied at the half inch green stage (15 Apr), the first NTN-33893 treatment was applied at the early pink stage (22 Apr), and the second NTN-33893 and Vydate treatments were applied at the pink stage (25 Apr) of ‘Golden Delicious’ development. A regular fungicide schedule (Dithane 75WP, Captan 50WP, and Nova 40WP) was maintained throughout the season. Post-bloom insecticides (Guthion 50WP) were applied at 1- to 2-week intervals beginning at petal-fall in early May. Effectiveness of the sprays for RAA control was evaluated by counting the total number of RAA injured clusters/tree and total number of damaged apples per tree (both cvs) in a 5-minute sample for each variable. WALH was sampled by counting the number of nymphs present on 25 injured leaves per tree (‘Yorking’). Also, 200 leaves per tree (‘Yorking’) were randomly sampled for evidence of stippling caused by WALH feeding.