Slime mold on grass is usually a temporary surface growth, not an infection of the grass plant. It can look alarming, but confirmed turf slime mold generally needs no pesticide. Let it dry, then gently brush or mow away the visible material if its appearance bothers you.
First check that slime mold is what you have. White powder, cottony growth and dead patches can have other causes. Photograph the coating close up and the surrounding lawn before disturbing it, especially if the grass itself is declining.
What you are seeing
Slime molds are not true fungi. Their visible spore-producing structures can coat grass blades, using the plants as support. The Penn State turfgrass guide explains why they appear among lawn-disease guides even though they do not infect the turf.
Growth may follow damp weather and can change appearance as it dries. A heavy coating may temporarily shade the blades, but that is different from a pathogen destroying plant tissue. A single occurrence does not prove that you have fertilized incorrectly or neglected the lawn.
What to do now
If identification is clear and the turf beneath is sound, waiting is reasonable. Once the growth is dry, use gentle brushing or routine mowing when ground conditions permit. Avoid aggressively raking wet, soft turf simply to remove a cosmetic coating.
Do not dethatch an entire lawn or repeatedly remove healthy clippings solely because slime mold appeared. Those are separate maintenance decisions. Fungicide is not a useful default response to a confirmed slime-mold occurrence, and professional chemical treatment is not normally necessary.
Reduce persistent wetness without promising prevention
Review irrigation if the lawn remains unnecessarily wet. Check runoff, drainage and shade, and water according to the grass and soil rather than a permanent daily schedule. Investigate a genuine thatch problem before arranging disruptive removal.
Weather can still produce another appearance. Neither a lawn-care service nor a changed watering schedule can guarantee that slime mold will never return. Judge the lawn by plant health as well as surface appearance.
When to obtain a diagnosis
Seek local extension help if patches are dying, the coating cannot be identified or symptoms persist after the visible material disappears. Include the grass type, recent weather and any products applied. Do not assume every white growth is slime mold or that an unidentified substance is safe to eat or handle.
Keep children and pets from investigating unknown growth while you identify it. The horticultural point is that confirmed turf slime mold generally does not require treatment of the grass; it is not a blanket health assessment of everything growing in a lawn.
