Prepare now for summer diseases in mums

With mum season just around the corner, now is the best time to prepare for managing summer diseases. Take time to identify possible threats, develop preventive measures and formulate a treatment protocol before diseases infect your mums this summer.

// Identify possible threats

The first step in preventing and managing summer diseases in mums is identifying key threats:

• Botrytis, also known as gray mold, often looks like brown, water-soaked spots on petals, leaves or stem cankers. Infected plant parts may become covered with gray to brown, powdery masses of spores. Infected buds may fail to open.
• Powdery mildew first appears in mums as a powdery, white to ash-gray growth on leaves and stems. As the disease progresses, leaves may become distorted and severely infected leaves will shrivel and die.
• White rust is characterized by white, pinkish, or light brown pustules on the leaf undersides and white or yellow to pale green spots on upper leaf surface. As the disease progresses, leaf distortion, discoloration, defoliation and even plant death can occur.
• Brown rust can be identified by its yellowish-green spots on upper surfaces of leaves and dark brown pustules on the undersides of leaves. The damage caused by brown rust is often minor. However, with severe infections that damage large areas of leaves may cause defoliation and reduced flower production.

// Develop preventive measures

To help protect your mums from the threat of disease, implement the following preventive measures:

• Manage relative humidity: Since high humidity is often a favorable condition for disease development, keeping the relative humidity below 80 percent can help minimize the threat of disease in mums. Keeping the greenhouse dry at night, when the temperature drops, is an inexpensive method to keep relative humidity down.
• Space plants properly: Avoid overcrowding your plants to improve air circulation and relative humidity at the plant level. This proper plant spacing can also help mitigate the spread of disease from one plant to another.
• Improve air circulation: Improving air circulation helps to remove free moisture from the plant canopy. Often, the result is a drier microclimate with less favorable conditions for disease development.
• Avoid overwatering: Water your plants just enough to prevent excess water on the floor. Watering early in the day can also help ensure that plant surfaces are dry before evening. This practice helps decrease humid conditions that are favorable for disease.
• Practice good sanitation: Remove diseased flowers and leaves from affected plants. Sanitize the area thoroughly to avoid recontamination.
• Scout regularly: Scouting for signs of disease on a regular basis can help you catch diseases early. Once disease symptoms are noticeable, it is important to act promptly to prevent the spread to other plants.

// How to treat disease

Apply preventive fungicides at the first signs of foliar disease. Broadform^® fungicide is a strong rotational fungicide that offers long-lasting residual protection from Botrytis and other key pathogens when conditions are favorable for disease development in mums.

// More information

Contact your Envu Ornamental Specialist to learn more.