Spatially Targeted Applications of Reduced-Risk Insecticides for Economical Control of Grape Berry Moth, Paralobesia viteana (Lepidoptera: Tortricidae).

Abstract

The grape berry moth, Paralobesia viteana Clemens (Lepidoptera: Tortricidae), is a key economic pest of vineyards in eastern North America, and prevention of fruit infestation is particularly challenging along vineyard borders that are adjacent to wooded areas containing wild grape (Vitis spp.). For three years, infestation and damage in vineyards where reduced-risk insecticides were applied to borders at timings based on a degree day model (Integrated Pest Management program) were compared to that in vineyards where broad-spectrum insecticides were applied across the whole vineyard (Standard program). Infestation at vineyard borders immediately prior to harvest was consistently lower in IPM vineyards than in Standard program vineyards, and in two of the years this was also true at veraison (fruit coloring). Grape berry moth infestation was similar between treatments at vineyard interiors throughout the study, despite no insecticide applications to the interiors of the IPM program vineyards. Populations of two other key vineyard pests, the eastern grape leafhopper, Erythroneura comes (Say) (Hemiptera: Cicadellidae), and Japanese beetle, Popillia japonica Newman (Coleoptera: Scarabaeidae), were not significantly different between programs, and natural enemy captures on yellow sticky traps were also similar. The per hectare cost of insecticides applied in the IPM program was consistently lower than for the Standard program, with a significant difference in the third year of this study. We demonstrate how spatially selective applications of reduced-risk insecticides can provide improved control of grape berry moth at lower cost than standard broad-spectrum insecticide-based programs.