Botrytis bunch rot is one of the most important diseases of grapes worldwide. Botrytis bunch rot infection can cause huge economic losses in grape production due to the preharvest infection in the field, which leads to reduced yield and postharvest losses during storage.

In collaboration with the Michigan State University grape team and funding from Project GREEEN and Michigan Craft Beverage Council, we are releasing a new Michigan Grape Facts resource for growers battling bunch rot or simply wanting to keep informed. Michigan Grape Facts: Managing Botrytis Bunch Rot is now available at the MSU Extension Grapes website. This fact sheet covers disease symptoms, disease cycle and management of botrytis in vineyards.

Take-home messages:

• Avoidance – Avoid cluster damage from other pests such as insects, birds and other grape diseases.
• Exclusion – Exclude the pathogen by harvesting in a timely fashion and increasing canopy airflow.
• Resistance – Choose resistant varieties when possible.
• Protection – Protect flowers and clusters with fungicides when the infection risk is high.
• Eradication – Eradicate old canes and clusters each season.