Apple, Insecticide Test, 1986

Test pesticides were applied as dilute sprays (270-300 gal/acre) to mature apple trees planted 40 by 40 ft apart. A completely randomized design was used, with 3 replications (cultivars) per treatment. Compounds were applied with a handgun sprayer at 500 psi on the following dates; 18 Apr (pink [P]), 7 May (petal fall [PF]), 23 May (first cover [1C]), 4 Jun (second cover [2C]), 18 Jun (third cover [3C]), 30 Jun (fourth cover [4C]), 14 Jul (fifth cover [5C]), 28 Jul (sixth cover [6C]) and 13 Aug (seventh cover [7C]). Treatments containing Asana also included Captan 50 WP at 0.5 lb/100 gal; all other treatments included Cyprex 65 WP at 0.5 lb/100 gal. Mite populations were assessed by sampling 25 leaves collected at chest height from the periphery of each tree; in the laboratory, mites were brushed from the leaves onto glass plates coated with Tween 20. Spotted tentiform leafminer (STLM) and white apple leafhopper (WALH) infestations were evaluated by counting infested leaves per tree. The number of infested terminals per tree was used to evaluate potato leafhopper (PLH) and green apple aphid (GAA) infestations. Woolly apple aphid (WAA) infestations were evaluated by counting infested areas per tree.