Grape Growing Problems

Identification

• Grapes are susceptible to the fungal disease Botrytis bunch rot, also referred to as gray mold of grape. The disease is caused by Botrytis cinerea. If not controlled in time, the disease can cause serious damage to fruit in storage or on vines.

Symptoms

• The fungus infects the old flowers, and then moves to leaves and ripe fruit that are growing densely, are damp or near the ground. There is a fuzzy, brown fungal spore growth on infected areas that gradually spreads to the stems. Affected areas start to rot and shrivel with a flat, hard, black mass under the rotting areas.

Management

• Keeping vines well ventilated helps to minimize chances of disease. Trim foliage in dense areas to let light and air inside the canopy. Do not use excessive nitrogen fertilizers. Prune affected areas and harvest fruit early if possible before anticipated prolonged humid or wet weather.