Secondary Insecticide Testing on Apple, 1997

Dilute sprays were applied with a hand sprayer (450 psi) at tight cluster (2 May), pink (12 May), petal fall (3 Jun), and as cover sprays on 11 Jun, 25 Jun, 7 Jul, 22 Jul, 6 Aug, and 20 Aug. Oil was applied at tight cluster in the DuPont program, followed by Asana at pink; Guthion + Vydate at PF; Vendex, Lannate, and Guthion at IC; Lannate + Guthion at 2C, 5C, and 6C; and a mixture of Asana + Guthion at 3C and 4C. In the Knack treatment, Knack 0.86 EC (0.37 oz (AI)/100 gal) was applied at pink, Guthion 50 W (4.0 oz (AI)/100 gal) was applied at petal fall, IC, 2C, 4C-6C, and Knack 0.86 EC (0.27 oz (AI)/100 gal) + Guthion 50 W (4.0 oz (AI)/100 gal) was applied at 3C. All other treatments were applied at petal fall and in the first through sixth cover sprays. Treatments were replicated 3 times (two 6-tree plots and one 8-tree plot) and arranged in a RCB design. At harvest (8-14 Oct), 200 apples were picked from the ‘McIntosh’ and ‘Cortland’ trees in each replication and examined for insect damage. Also, 100 ‘Golden Delicious’ apples were picked from each replication in the Diazinon treatment, the standard Guthion treatment, and the check plot and examined for fruit russeting. Apples were divided into three categories according to the estimated amount of russeted surface: low (0-3%), medium (5%-50%) and high (>50%). ERM and predaceous mites were sampled on 25 randomly selected ‘McIntosh’ leaves/replication on 24 Jun, 14 Jul, 24 Jul, and 8 Aug. On 17 Jun the first generation of WALH were counted on 50 spur leaves (‘Rhode Island Greening’, Rep I and II, and ‘Cort-land’ trees, Rep III) and the second generation was sampled on 28 Aug. STLM tissue mines from the first generation were counted on leaves from 25 ran-domly selected fruit clusters on 11 Jul. Second-generation STLM tissue mines were counted on 8-10 distal leaves on 20 randomly selected “hardened off” ‘Rhode Island Greening’ terminals/replication in Rep I and II and on ‘Cortland’ terminals in Rep III on 27 Aug.