Brown Powder In Lawn

Asked July 1, 2020, 8:20 AM EDT

Hi, I live in Annapolis. I installed an entire yard of sod in March. It was doing fine until about two weeks ago. Now I get a brown Powder on the grass, and in about 2 days it is dead. It's killing my whole yard. I brushed the grass with my finger as you can see in the picture and the brown Powder came off. Help?

Anne Arundel County Maryland

3 Responses

This looks like slime mold, a fungus on the leaf blades. Warm weather and moisture favors production. The fungi does not damage the turf and no control is necessary.
It can be removed by a strong stream of water or when you mow.

You did not mention what the sod consisted of. Certified sod of a cool season grass is usually turf type tall fescue with some blue grass mixed in to help it knit together. We notice some typical summer leaf spot diseases like brown patch. This disease does not kill the crown of the turf. Most tall fescues lawns will recover with proper fall fertilization and the return of rainfall.

We notice some ragged blade tips. Keep your mower blades sharp and mow high.
About 3 - 4" or set the mowing height on your mower's highest setting, especially in the hottest, driest part of the summer.


Thanks much. If it causes no harm then why does the grass die a few days after I see the mold? Will that come back? I bought the sod from a local company. They said it is a blend designed for Maryland. Thanks again for quick response.

The death of any blades covered by slime mold is probably coincidental, though if it were covering the blade for long enough, perhaps it is impacting photosynthesis or making just damp enough of a microclimate that the disease organisms themselves are prospering. The presence of the slime mold could very well indicate consistently moist conditions, as they do not appear in areas that stay dry or dry quickly (sidewalks, etc).

Since the crown (main growth points at soil level) of the sod is not affected by brown patch, healthy grass blades should grow to replace the diseased ones. This may not happen more notably until fall, since Fescue is a cool-season grass which does semi-dormant in the heat of summer. As our nights begin to cool off at the end of summer, more vigorous growth should resume.