Mushrooms are the above-ground fruiting or reproducing structures of a fungus that thrives on decaying organic matter in the soil. Mushrooms thrive in warm damp areas, frequently sprouting up in a lawn after wet weather. They are seldom found in cool, dry spots. In cold winter areas, they disappear with the first frost, and return with wet spring weather.
Mushrooms may appear in the lawn individually or in clumps. Fungi with a clumped growth habit are usually harmless to grasses but are objectionable because they are unsightly and occur repeatedly.
The easiest and most practical solution, although it is only temporary, is to break the mushrooms with a rake or lawn mower. There is no chemical treatment for the control of mushrooms or toadstools.