Thriving in cool, humid environments, Botrytis can be problematic from late fall into winter. It is particularly threatening to newly propagated material like germinated/young seedlings and unrooted cuttings. Plants that have been or will be boxed, stored or transported are also highly susceptible because humidity and ethylene levels contribute to plant stress.

Initial Botrytis infections result in water-soaked spots on foliage and flowers. Once established, gray mold can quickly spread throughout the crop and production area. It is important to continually check plants as this disease can appear virtually overnight under the right conditions.

Cultural Tips

• Provide a clean, dry growing environment
• Irrigate early in the day to reduce how long leaves are wet
  • Botrytis spores need a film of water to germinate, so keeping the leaves as dry as possible reduces the chances of the fungus being able to thrive.
• Provide good plant spacing and horizontal air flow
• Clean and sanitize between crops
• Keep humidity low by heating or venting
• Immediately remove wounded and diseased plants as well as dead flowers and leaves to limit spore production and spread

Cultural practices alone will not be successful in eradicating the disease, but can limit development and further contamination. Implementing a rotation program in addition to enhancing your cultural practices are the most reliable strategies to prevent Botrytis.

Propagation and post-harvest environments, such as coolers and shipping boxes, often create a moist, humid environment that fosters Botrytis so preventive action is necessary. Applying a rotation of effective fungicides during production, like Mural^®, and prior to storage and shipping will protect the crop and ensure its quality for sale after it leaves production.

For more tips for how to defend against Botrytis, including a product rotation program, view our Botrytis rotation program.

All photos are either the property of Syngenta or are used with permission.

©2018 Syngenta. Important: Always read and follow label instructions. Some products may not be registered for sale or use in all states or counties and/or may have state-specific use requirements. Please check with your local extension service to ensure registration and proper use. Mural^® and the Syngenta logo are trademarks of a Syngenta Group Company.