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Friday - June 22, 2007

From: Austin, TX
Region: Southwest
Topic: Diseases and Disorders
Title: Saprophytic fungus on mulch
Answered by: Joe Marcus


I just did some major landscaping in my west Austin, TX backyard. I added many native plants and mulched all of the new beds. I did this just before the heavy rains in the past two weeks. I now notice a powdery white substance in the mulch (not on the plants). Is this powdery mildew? Whatever it is, do you have any suggestions regarding what to do about it? Thank you.


Chances are the white powdery substance you describe is a saprophytic fungus growing on the mulch. Saprophytic fungi are those that live strictly on decaying organic matter. Most such fungi are incapable of doing harm to plants. It is very common to see blooms of fungal growth on shredded bark and other mulches after rainy spells.

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