Apple Insecticide Evaluations, 1983

Abstract

Abstract Insecticides were applied to trees in four single-tree replications in a randomized block design, using a Swanson DA400PT024 airblast sprayer. The sprayer traveled at 1.07 m/sec and delivered 2805 1/ha for delayed dormant and pre-pink applications, and 935 1/ha for the remainder of the season. Dates of application were 13 Apr. (delayed dormant (DD)), 28 Apr. (pre-pink (PP)), 11 and 12 May (petal fall (PF)), 27 May (first cover (lc)), 13 June (second cover (2C)), 25 and 28 June (third cover ((3C)), 12 July (fourth cover (4C)), 28 July (fifth cover (5C)), 15 Aug. (sixth cover (6C)), and 30 and 31 Aug (seventh cover (7C)). Baycor 50WP and Streptomycin were also applied separately to all treatments. Trees were evaluated for rosy apple aphid control on 1 and 2 June by walking around the periphery of the trees and counting colonies. Treatment effectiveness was determined for apple aphid on 1 and 2 June by counting infested leaves on each of 20 terminals (10 from each sprayed side) around the periphery of trees at a height of 1.8 m. Control of white apple leafhoppers was determined by counting nymphs found on 25 leaves selected from outside of each tree. Effects of treatments on European red mites were determined by sampling 25 leaves from the periphery of each tree, removing mites with a mite-brushing machine and counting active mites with a binocular microscope. Effects on Stethoruspunctum were determined by counting adults and larvae observed during a 3-min period while walking around the tree periphery. Treatment effectiveness on fruit feeders was determined by scoring for injury 400 apples per treatment (100 per replication), plus all fallen apples found from 19-21 Sept.