Western Cherry Fruit Fly Control on Tart Cherry, 1990 and 1991

Plots were located in a 10-yr-old orchard with under-tree sprinkler irrigation. The experimental design was a randomized complete block with 5 double-tree replicates/treatment. Treatments were separated by unsprayed buffer trees. Dilute sprays were applied to runoff with a handgun sprayer operated at 200 psi and with an output rate of 3800 liters/ha. Yellow sticky traps with additional ammonium carbonate bait were placed in the orchard to determine activity of the first flies, which were caught on 1 and 12 Jun in 1990 and 1991, respectively. In 1990 the dates of application were as follows: Cygon 400 on 6 Jun, Guthion 35 W on 6 and 27 Jun, Imidan 50 W on 6 and 20 Jun, and diazinon 50 W on 4 Jul. In 1991 all insecticide treatments were applied on 18 Jun and 2 Jul. At harvest (13 and 17 Jul in 1990 and 1991, respectively), 50 fruit were randomly collected from each tree and 50 fruit were picked up from the ground underneath each tree to determine percent infestation by WCFF. WCFF-infested fruit ripened prematurely and dropped to the ground early.