Powdery Mildew: The White Dust That Isn't Dust

Powdery mildew is a common fungal disease that affects a wide range of trees, shrubs, and ornamental plants throughout the growing season. It appears as a white or gray powder-like coating on leaves, stems, and new growth. While it is rarely fatal to mature trees, untreated infections can weaken plant vigor, reduce photosynthesis, and negatively impact overall appearance and health.

This disease thrives during periods of warm days, cool nights, and high humidity. Unlike many fungal pathogens, powdery mildew does not require standing water to spread, making it especially common during mild weather with poor air circulation. Trees and shrubs growing in shaded or overcrowded landscapes are often more susceptible.

Early symptoms may include leaf curling, distorted growth, yellowing foliage, or premature leaf drop. Repeated infections over multiple seasons can stress trees and make them more vulnerable to secondary pests and diseases.

Proper tree preservation practices are essential in managing powdery mildew. Selective pruning to improve airflow, maintaining healthy soil conditions, and reducing plant stress can significantly limit disease development. In some cases, professional fungicide treatments may be recommended to protect valuable specimens.

Powdery mildew looks exactly like someone dusted your landscape with powdered sugar. Unfortunately, your trees aren't getting dessert.