Toadstools are the fruiting bodies of a class of fungi known as Basidio-Mycetes. The vegetative part lives underground, feeding on dead plant material and speeding the process of its decay. When the ideal environmental conditions occur, the fungus reproduces via spores produced in the toadstools which are then dispersed by wind.
When the supply of nutrients is used up the fungus dies out and no more toadstools are produced. They normally occur during the turf's first season. The fungus is not a disease, unlike those which cause "fairy rings" in the turf. In fact, breaking down dead material is beneficial to the turf. The small brown toadstools that occur most frequently in new turf are not poisonous. However, their consumption is not recommended.
A traditional remedy for controlling toadstools is to apply a solution of two ounces of Epsom salts (magnesium sulphate) dissolved in a gallon of water per sq. yard of affected area. As toadstools are mainly composed of water they soon dry up and blow away. They can also be mown out or swept with a besom broom.