Strange patches on your grass? Could be slime mold

Published 5:18 pm Friday, June 16, 2017

Slime mold in are a primitive fungi that sucks nutrients from dead and decaying organic matter in the soil or thatch of lawn, as shown to the left.

By: Ty Torrance

have received a couple of calls about patches of a black or blue/gray mold like substance on someone’s lawn. In fact, there is a nice patch of it in the turf around our extension building.

This is slime mold and it may be found on almost any cultivated lawn or weedy grass. It appears after prolonged periods of leaf wetness and will be seen from spring to fall. It is basically a superficial mold using the blades of grass as structural support. While its appearance in your lawn is often unsettling, it usually does not harm the grass unless it gets so thick that it blocks photosynthesis. The discoloration is due to the sporulation of the fungus and will often be described as “it looks like patches of soot were dumped on my lawn” and “it comes off on your fingers when you touch it”.

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Slime molds are “primitive” fungi and they obtain their nutrients from dead and decaying organic matter in the soil or thatch of lawn. It is more apt to develop in areas of poor drainage or dense thatch. Chemical treatments are not recommended and normally when things dry out or when you mow the grass the slime mold disappears until the next time that conditions are right for its development.

For more information about these or other subjects please contact our office (229) 248-3033.