Lawn diseases of various types can strike almost unexpectedly due to bad weather, unseasonable conditions or the spreading of disease through the soil. None are harder to control than the common fungi, which can wreak havoc on an otherwise healthy and well-fed lawn.
Mushroom spores travel throughout the air on air currents and through the soil. Once the fungi spores are in a suitable location to grow, such as your lawn, the spores begin to germinate, sending out long tendrils called hyphae. Fungus feeds off dead material such as grass, leaves and decaying wood.
Visible mushrooms in the yard are actually the fruiting portion of the hypae that is growing through the ground. Removing fungi from the surface area of the lawn does not destroy the underlying problem.
One of the most common lawn diseases caused by the growth of fungi is "fairy rings," a circular or semicircular green band that appears in the yard due to the production of fungi. These can be 1 to 12 feet in diameter. Due to poor nutrient absorption within the circle, grass may not grow.
Prevent fungi by practicing proper maintenance of the lawn, such as raking dead leaves and grass. Aerating the lawn will prevent the buildup of thatching, dead grass left by a lawnmower, which is a breeding spot for fungi. Aeration may remove vital parts of the growing fungi as well.
Probing the lawn with a trowel will help you determine how deep the fungi has grown. If the fungi is less than three inches thick, a good aeration may be able to remove significant portions of the fungi. Chemical fungicides can be applied to the lawn with a probe, or spray, to seep into the soil and kill fungi. Some fungicides are illegal to use in certain states, and within a certain clearance of water, so checking local guidelines is essential before application.