Apple, Insecticide Test, 1985

Test pesticides were applied as dilute sprays (210-220 gal/acre) to 21-year-old ‘Rome Beauty’ apple trees planted 40 ft by 40 ft apart. A completely randomized design was used, with 4 replications per treatment. Applications were made with a handgun sprayer at 400 psi. Dates of application were 22 Apr (tight cluster (TC)), 8 May (petal fall (PF)), 22 May (first cover (1C)), 3 Jun (second cover (2C)), 18 Jun (third cover (3C)), 1 Jul (fourth cover (4C)), 17 Jul (fifth cover (5C)), 29 Jul (sixth cover (6C)) and 13 Aug (seventh cover (7C)). All treatments included Captan 50WP at 2 lb/100 gal. Mite populations were assessed by sampling 25 leaves, collected at chest height from the periphery of each tree, and brushing the mites onto glass plates coated with Tween 20. Green apple aphid (AA) infestations were evaluated by counting infested terminals per tree. White apple leafhopper (WALH) and spotted tentiform leaf-miner (STLM) infestations were evaluated by counting infested leaves per tree. The number of curled clusters, infested areas and infested branches per tree were used to evaluate infestations of rosy apple aphid (RAA), woolly apple aphid (WAA) and Japanese beetle (JAP), respectively.