Emmalea Ernest, Extension Fruit & Vegetable Specialist; emmalea@udel.edu
Gray Mold (Botrytis Fruit Rot) and Anthracnose Fruit Rot, two important diseases affecting strawberry fruit, are best managed with timely control during the flowering period. For Botrytis, most affected fruit are the result of infections that occurred during flowering. For Anthracnose, flowers can become infected and produce spores that later spread to nearby ripening fruit.
The strawberry section of the Mid-Atlantic Commercial Vegetable Production Recommendations includes fungicide recommendations for both diseases. Timing of fungicide sprays should be informed by weather conditions. NEWA offers a Strawberry Diseases Model for predicting risk of infection by Anthracnose and Botrytis based on DEOS weather stations in Delaware. This tool includes risk levels based on the 5-day weather forecast. I have compiled the NEWA Strawberry Diseases Risk Levels for seven Delaware locations in the table below. Risk of infection has been low, but there is a high risk for Botrytis infection and a moderate risk for Anthracnose infection on Friday, April 12.
Strawberry Anthracnose and Botrytis Infection Risk from NEWA on April 11, 2024
When risk levels are low (green highlight) fungicides are not needed to control disease. When risk levels are moderate (orange highlight), fungicides should be applied if other factors are present that increase disease risk, such as susceptible varieties or a history of disease in the planting, AND fungicides have not been applied for 7-14 days. When risk levels are high (red highlight) apply a highly effective fungicide as soon as possible if no fungicides have been applied for 7-14 days.
You can get the most recent and relevant strawberry disease risk information by checking the NEWA model for the DEOS station closest to your field.