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We’ve had a lot of calls over the last couple weeks from people asking about their hostas.   “Are they diseased?”  “Are the rabbits eating them?”  “Is it a fungus?”  “Are they dying?”

Well, the answer is, it’s “grey mold”.  We’re seeing a lot of grey mold on hosta plants this year in Mid-Michigan.

What’s the cause?

Plant mold diseases are caused in certain hot and humid conditions.  We had 6 warm days of rain in early May, followed by cool nights.  The hostas got wet and weren’t able to dry out.

How do I know if my hostas have grey mold?

The symptoms are, as shown in the image above, a grey powdery appearance with browned out edges.  The disease closely resembles herbicide damage, except it doesn’t have the curling of the leaves.   If the mold is severe, it can kill a plant.  Most cases we are seeing are cosmetic issues, and with proper care, the plants can fully recover.

What should I do if my plants have grey mold?

If not severe, you’ll want to trim off the dead/dying leaves and use a balanced fertilizer.

In severe cases, to save the plant, use a broad-spectrum fungicide, such as Dow Agroscience’s “Eagle” brand.  And, as always, feel free to give us a call any time for further help.