Foliar Anthracnose

Disease

Anthracnose, Foliar Blight Anthracnose

Colletotrichum cereale

Photos

Anthracnose can occur as both a foliar infecting and crown infecting disease. Foliar infecting anthracnose is characterized by irregularly shaped patches of yellow-bronze turf, ranging in size form a few inches to several feet. Leaf lesions initially appear as elongated reddish brown spots on the leaves, which may enlarge, eventually encompassing the entire leaf blade. Black, pepper-like, fruiting bodies (acervuli) of the fungus can be seen on the foliage and crown as the disease progresses.

The fungus can overwinter as a saprophyte in plant debris or as a pathogen in infected tissue. It is most often seen in turf growing under low soil fertility and high temperature stress. The pathogen usually infects tissue from the tip down, especially on freshly mown turfgrass. The disease is most severe in areas of compaction heavy traffic, and poor soil drainage, and can occur in a wide range of temperatures.

Crops Affected: turf

Damage

The location of this disease is golf courses. General symptoms are a circled, spotted, wilted, or irregular grass. Foliar symptoms are the grass turning yellow, brown, or orange, or becoming spotted. This can occur during the months of May, June, July, August, and September. Hosts of the disease are Kentucky Bluegrass, Creeping Bentgrass, and Annual Bluegrass.

Management

Anthracnose can be managed by avoiding or relieving plant stress in the spring and summer with light nitrogen applications (1/2 lb per 1000 ft²) when it occurs. Reducing wear and tear stress by redirecting traffic, and promoting healthy turf development with common fall and spring practices such as aeration and topdressing also help turf tolerate extended periods of summer stress. Creeping bentgrass seems to only be susceptible to anthracnose in warmer climate areas (near or south of the transition zone). A range of susceptibilities exist among the many cultivars of Kentucky bluegrass, perennial ryegrass, and the fine-leaf fescues that are listed as susceptible.
Anthracnose can be managed with systemic fungicides like azoxystrobin, myclobutanil, trifloxystrobin, fenarimol, propiconazole, pyraclostrobin, thiophanate methyl, and triadimefon, applied every two to three weeks. Contact fungicides such as chlorothalonil, mancozeb, or maneb plus zinc sulfate can be used in combination with the aforementioned systemic fungicides.

MSU Extension Turf