Healthy Japanese maples can be beautiful additions to your garden, but occasionally they can be affected by a common fungus called powdery mildew. This can be a tough fungus to deal with, but if you know the basics, you can identify it and may be able to keep it from spreading.
Powdery mildew is usually easy to identify. It looks like a white powdery spot or area on the top of the leaves or stems, making the plant look like it has been dusted with flower. While most fungus do not like hot weather, powdery mildew prefers hot weather and humidity. Also unlike other fungus, it does not require water to infect the plants.
If you find your Japanese maple, crape myrtle, or dogwood have powdery mildew, try to remove as much of the infected leaf as you can, and avoid overhead watering. Increasing the air movement around the plant by pruning overgrown branches or vegetation can help as well.
You can spray fungicides that target powdery milder, or if you prefer the natural route, baking soda or milk may help. Hopefully with some diligence and luck, you can use these steps to help deal with this disease if it occurs in your garden.
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