“Help, my plant is covered in a white, powdery fungus! What do I do?” First, don’t panic. While powdery mildew may not look pretty, it rarely causes significant damage except in cases of severe ...

Powdery mildew is a fungal disease affecting many plants, causing a white or gray coating on leaves and slowing growth. The fungus thrives in warm, dry weather with high humidity, especially in ...

“My red rhododendron looks as if it has a layer of ash or white powder on it (above). What should I do?” asks Birds & Blooms reader Steven Graves of Aptos, California. Horticultural expert Melinda ...