Grape Berry Moth, 1988

Abstract

A mature Concord vineyard of 15 acres with a known history of GBM infestation was used for insecticide evaluations. The vineyard rows were 9 ft apart and the vines set at 8 ft apart within the row. Each treatment consisted of 45 vines (3 rows × 15 vines) and was replicated 4 times in a randomized complete block design. Insecticides were applied as foliar sprays with a hooded boom over-the-row sprayer operated at 500 psi, and equipped with 7 nozzles/boom on each side with No. 2-1/2 (mm) discs and 3-hole whirl plates. From 2 to 6 applications were made between 21 Jun and 11 Aug. The conventional 3-spray regimen for control of GBM, comprising treatments of postbloom, 10 d postbloom, and early Aug, was evaluated and contrasted with alternative application timings. Cover sprays consisting of a tank mix of triademefon (Bayleton) at 1 oz. AI and maneb (Dithane M-22) at 1.5 lb Al/acre were applied to all plots on 15 Jun and 7 Jul to suppress powdery mildew, black rot, and downy mildew. Injury assessment was made on 6 Sep and was based on the number of berries injured by GBM larvae per 100 clusters in each replication (10 clusters from 10 vines/replication). Carbaryl SOS applied at 2 lb AI and Parathion 8EC applied at 9 oz AI were the standards. GBM infestation in the block was considered average or slightly above average in 1988. The threshold for GBM damage is 2% damaged berries.