Addressing Late-Season Grape Berry Moth Damage

Abstract

The concern over late season grape berry moth (GBM) damage has prompted growers and processors in the Lake Erie region grape industry to take a closer look at the management strategies available to them and the economics of the direct berry damage caused by this pest. The goals of this project are to look at the parasitic wasp, Trichogramma ostriniae, to determine if it would parasitize grape berry moth eggs in the field and to look at the economics of late season losses to this pest and how they relate. An oversimplification of the ‘economics of’ GBM damage is whether a load is rejected at the processing plant. While a trailer load of $200 a ton ‘Concords’ would result in a loss of $4,000 it is well understood in the industry that many times this trailer load is taken home, reworked, and passed through inspection on the second try. This project showed that a bigger concern to growers should be in-field loss due to weight-loss from direct feeding on the berry by the GBM larvae, or the premature drop of fruit due to infestation by GBM either alone or combined with Botrytis and secondary rot infections.