Turf: Fungus and Disease

Turf disease and fungus can be prompted by high moisture, humidity, or heat. As spores are transferred (either wind, foot traffic, water, mower, etc), funguses and diseases are prone to infect new portions of a lawn or uninfected plants. Sometimes fungus can be corrected by taking just a few simple steps, and sometimes a fungicide is warranted. Below is information about common funguses to this area.

	Anthracnose Anthracnose on turf can cause yellowing and thinning of the lawn, usually starting with the older growth then spreading to the newer growth. The lesions are round or oval, reddish-brown, and usually outlined... Read more
	Brown Patch Visually, brown patch is circular patches (a few inches to a few feet in diameter) of dead, brown grass sometimes outlined by a ring of violet. This disease appears during high humidity and high temperatures... Read more
	Dollar Spot Dollar spot begins as small irregular light brown or straw colored patches. Dollar spot is active during moist warm weather and can spread forming large areas of infected turf. The leaf of the grass displays lesions... Read more
	Gray Leaf Spot Gray leaf spot generally affects tall fescue and rye grass - though it has affected other cool seasoned grass types as well. The beginning stages of Gray leaf spot are small lesions which mimic the look... Read more
	Gray Snow Mold Gray snow mold appears on lawns when snow melts in spring and patches of straw colored turf a few inches to a few feet in diameter can be seen. The orange sclerotia is the key to identification. As snow... Read more
	Necrotic Ring Spot Kentucky Bluegrass, Fescue's, and Bentgrass can be affected by Necrotic Ring Spot. This disease begins as light green patches scattered throughout the lawn, though as the disease grows... Read more
	Pink Snow Mold Pink snow mold can affect lawns in autumn, winter and spring. Unlike gray snow mold, pink snow mold does not require the insulation of snow to start the pathogen (although snow cover indeed... Read more
	Powdery Mildew Powdery mildew appears in shaded areas that have little to no air circulation. A white, fine powder forms on the blade of the grass sometimes covering the whole blade. Kentucky Bluegrass is... Read more
	Pythium Blight Pythium Blight, also referred to as cottony blight or grease spot, is a rapid spreading disease that occurs during very humid weather patterns. Within a matter of days, pythium blight can wipe out a lawn... Read more
	Red Thread Red thread infects grass blades and leaf sheaths. The fungus is distinguishable by thread-like strands or web-like areas of coral-pink to blood-red on the tips of brown grass blades. This, as with all funguses, can be... Read more
	Rust Rust is favored by warm and humid conditions and develop most frequently on grasses subject to drought conditions, low nitrogen fertility and shade. The disease first appears on grass leaves as small... Read more
	Summer Patch Summer patch affects Kentucky Bluegrass, Annual Bluegrass and Fescue's. The disease appears during summer and is related to necrotic ring spot where rot is caused to the root and crown of the plant... Read more

Fungicides may be used as a preventative or corrective measure; they can work by either preventing or interfering with the germination process of the fungal spores or destroy the fungus outright. Contact fungicides will not be absorbed by the plant’s tissue and will only remain active on the surface of the plant in the location applied. This is beneficial since it rarely leads to the fungi building a resistance against the fungicide since the residual does not last long. Penetration fungicides may also be an option. This sort of fungicide not only penetrates the leaf of the plant (in which it can then travel to other portions of the plant) but may also be used as a contact fungicide. Penetration fungicides can be used to protect new growth from potential fungus attacks (especially if susceptible, such as perennial rye grass).

Other sites that provide a wealth of information on Turf diseases and funguses:
Ohioline.osu.edu and Plantclinic.cornell.edu