All turfgrasses
Slime Molds are caused by harmless, nonparasitic fungi, which spores are spread by the wind and are the most likely to appear abruptly, following lawn watering, and are more common during cool, humid or wet weather. This fungus initially makes a sudden appearance as a gray, watery white, or yellowish white slimy growth that crawls over the grass blades. After a few days, the growth changes into pinhead-size balls of purple-brown, black, white, or bluish gray, which are composed of fungus spores and feel powdery when you rub them between your fingers. An abundance of the powdery spores covering the grass may block the sunlight and turn the grass yellow.
In most instances, these unsightly molds will disappear if left alone. If you wish to remove them, sprinkle with a strong water spray during dry weather, rake them away, mow the lawn, or sweep the area with a broom. Chemical control is not necessary or useful.