Anthracnose

Plant stress and unbalanced fertility in soil normally trigger the anthracnose on grass and leaves. Photo: Charles Averre, N.c  State University, Bugwood.orgIf your lawn is going to be hit with a disease, anthracnose might be the one you want.

That’s according to Alfredo Martinez, associate professor and extension plant pathologist in the plant pathology department at the University of Georgia.

“While you don’t want this scenario to happen, if I could choose any disease to have, I’d probably choose a foliar disease and within these, I would probably select anthracnose,” he says, because the disease is a plant stress disease. “Without trivializing the disease, there are several cultural factors and practices that you can implement. Usually in anthracnose, fertility is important. Nitrogen and potassium levels should be optimal.”

Anthracnose is produced by a pathogen called Colletotrichum cereale (formely C. graminicola). Plant stress and unbalanced fertility in soil normally trigger the disease.
Stresses such as high temperature, root zone compaction, thatch accumulation, low fertility, drought, low mowing height and insect infestation make turfgrass susceptible to Colletotrichum cereale.

Cultural practices that reduce these and other stresses often help to limit anthracnose incidence and severity. These practices include core aerification, growing locally adapted, disease resistant grasses; correcting and/or avoiding low fertility or unbalanced fertility according to a soil test and local recommendations;  and relieving soil compaction by reducing traffic.

“Whenever I see some anthracnose, the first thing is to do a soil or plant tissue test to see the fertility levels – what is actually going on in there,” he says.

The author is associate editor for Lawn & Landscape. He can reach him at bhorn@gie.net.