What's eating my grape 'marquette'?

Grape 'Marquette' is a cold-hardy red wine grape bred partly from Vitis riparia. Its strong disease resistance reduces fungal pressure, but it still faces grape berry moth, Japanese beetle, and spotted wing drosophila. Deer are a serious winter threat in the upper Midwest where it is mainly grown. Grape berry moth is the principal insect pest.

Webbing and frass on flower clusters; larvae bore into berries in summer causing rot entry points. Use regional degree-day models to time Bt or spinosad at egg hatch. Mating disruption ties in commercial plots. Remove loose bark where larvae pupate.

Skeletonised leaves with lacy brown tissue between veins; heavy attacks reduce photosynthesis. Hand-pick early morning into soapy water. Pyrethroid spray during peak flight. Avoid pheromone traps near vineyard.

Berries soften and collapse prematurely; tiny larvae inside; secondary Botrytis infection. Monitor with traps from veraison; apply spinosad at first catch. Harvest promptly.

New shoot tips browsed in spring; heavy browsing can set back young vines by a full season. Deer fencing (minimum 8 ft) around the planting; tree-tube protection on individual vines in the first two years.