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.