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How to best prepare for cool-season diseases

Certain diseases favor cooler greenhouse conditions so it is important to stay ahead for a successful production season. Below are some tips on what to watch for in the months ahead.

Botrytis
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. Post-harvest environments often create a moist, humid environment that can contribute to plant stress and lead to Botrytis.

Initial infections result in water-soaked spots on foliage and flowers. Once established, gray mold can quickly spread throughout the crop and production area.

Rotating effective fungicides during production, like Mural®, and prior to storage and shipping is recommended to help ensure protection after crops leave production. Check out our Botrytis rotation program for a full product recommendation schedule.

Downy Mildew
Another common disease to watch out for in fall and winter is downy mildew. Recognizing early signs is critical to plant quality and health. Leaf discoloration or spotting, often within the veins, are the most common initial symptoms. When the fungus invades the plant internally, stunting, distortion and mortality can occur.

Subdue Maxx®, Segovis® and Mural fungicides, when used in a rotation, provide excellent control of downy mildew. Since they each have different modes of action, these products are framework for a strong resistance management program. Our downy mildew program includes rotation recommendations as well as scouting tips.

Powdery Mildew
Powdery mildews favor mild temperatures and reduced light intensity that can occur in the greenhouse this time of year. Infections can occur and spread quickly, reducing plant health and the value of the crop. Keep a close eye on your poinsettias, miniature roses, dahlia, gerbera and pansy crops, which tend to be susceptible.

Mural® and Heritage® fungicides have demonstrated strong control of powdery mildew diseases. Its broad-spectrum activity can also help prevent additional diseases, such as Botrytis and downy mildew.

Cultural Tips
To help prevent diseases in your operation, there are many cultural and sanitation practices that can be implemented, such as:

    • Irrigating early in the day to reduce how long leaves are wet
    • Providing good plant spacing and horizontal air flow
    • Cleaning and sanitizing between crops
    • Keeping humidity low by heating or venting
    • Immediately removing wounded and diseased plants as well as dead flowers and leaves to limit 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 is the most reliable strategy to prevent disease.

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©2019 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. Heritage®, Mural®, Segovis®, Subdue Maxx® and the Syngenta logo are trademarks of a Syngenta Group Company.