Extension Education Reduces Sprays, Boosts Sour Rot Control in NY Vineyards

Response

Cornell Cooperative Extension integrated field monitoring, applied research, and targeted outreach to improve sour rot management. The team monitored disease symptoms and weather conditions in vineyards on Long Island and in the Finger Lakes, providing direct feedback to growers. In 2025, CCE delivered educational updates to more than 100 growers and presented findings at regional meetings and industry events. Recommendations emphasized risk-based spray decisions and insecticide rotation to delay resistance. Project findings were incorporated into the 2025 New York and Pennsylvania Pest Management Guidelines for Grapes. CCE also developed and field-tested a daily sour rot risk model to guide decision-making.

Results

 In 2025, low pre-harvest disease risk allowed growers to reduce unnecessary insecticide applications. Historically, some growers applied three to four sprays before harvest. Reducing two applications per acre across 1,000 acres of susceptible grapes would result in an estimated savings of $60 per acre, or $60,000 in a low-risk year. Field testing showed that a model-based program required two sprays compared to five under a conventional schedule, without increasing sour rot levels. These outcomes demonstrate improved efficiency in pest management while maintaining crop quality.

Public Value

New York State benefits from more efficient and environmentally responsible grape production. By aligning pest management with actual disease risk, Cornell Cooperative Extension reduces pesticide use, lowers costs for growers, and supports the long-term effectiveness of insecticides. These improvements strengthen the economic sustainability of the state’s wine grape industry while protecting environmental quality.