Phlox #413061 - Ask Extension


Phlox #413061

Asked July 10, 2017, 10:47 AM EDT

My garden phlox are coming nicely but now some of them have a white  powdery substance on the leaves. What can I do or is this ok?

Ramsey County Minnesota

Expert Response

Thank you for the question.  Your phlox may have powdery mildew and here is what the University of Minnesota Extension has to say about it:
  • Powdery mildew is a common fungal disease that does not cause significant damage to plants.
  • Tolerate low levels of powdery mildew that do not reduce plant growth or flowering.
  • Look for powdery mildew resistant varieties in seed catalogs, on seed packages, and on plant labels.
  • At the end of the growing season, cut infected plants at the soil line and compost them.
  • Fungicides should only be used to protect high-value plants with a history of disease. Fungicides will not cure or remove existing powdery mildew infections.
Please check out this information on powdery mildew of phlox and click on the link at the bottom that takes you to more information:

Thank you for contacting Extension.
Anita Hoaglund Replied July 10, 2017, 7:02 PM EDT

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