It’s Only a Matter of Slime
This podcast details one of the lawn's most distressing looking (but practically harmless) fungi: slime mold.
- Slime Mold on a Cool-season Lawn Handout (PDF | 712KB)
Cooling temperatures and timely rainfall events can provide ideal environmental conditions for the appearance of one of the lawn’s most dreadful looking fungi -- something aptly named “slime mold”. However, as bad as this fungus looks, its bark is much worse than its bite and it is certainly not a problem that warrants chemical treatment.
This particular fungus is a saprophyte, a fungus that lives on decaying plant material in the soil. The fungi that incite the most serious diseases in our lawns are parasites -- fungi that can attack living plants. The grayish-black colored slime covering your turf’s leaf blades have a very similar appearance as if someone poured ashes from your fireplace all over the lawn. What you see are the fungi’s fruiting structures. During reproduction, the fungus elevates itself out of the turf canopy and onto the leaf blades in order to spread its spores as far as possible in the environment.
Outside of looking horrible, the only problem this fungus can cause is a short term blockage of sunlight for photosynthesis. A fungicide application is not warranted and instead, simply wash, broom, brush, drag, or mow the fungal fruiting bodies off the blades of your grass and the problem is solved. So, as bad as it looks, slime mold is not a serious problem for your lawn. But if looks could kill, this fungus would be deemed deadly!
Has this podcast been useful to you? Please let the Virginia Cooperative Extension staff know how we can better serve you in our quest to ensure that everyone knows how to keep their lawns green and our water clean.