Summer Patch
Summer Patch
Photo courtesy of North Carolina State University
The fungus Magnaporthe poae causes summer patch. It affects Kentucky bluegrass and bent grass. Disease symptoms will appear through the summer; however, the infectious period is in the spring and therefore, once the symptoms are seen, it’s too late to treat.
Signs and Symptoms
Summer patch symptoms begin as dark, circular patches that appear drought-stressed. These patches turn a light-straw color. Patches may be in the shape of streaks, crescents or circles. Circular patches may form “frog-eyes” or brown areas with green turf in the center. Affected crowns usually die.
Favorable Conditions:
Daytime temperatures of eighty to ninety-five and night temperatures above seventy favor disease occurrence. Humid environmental conditions and heavy thatch accumulation can contribute to disease. Stressed turf grass (specifically drought-stressed) is especially vulnerable.
Cultural Prevention and Control
Regular aeration and adequate moisture and fertility can help prevent summer patch from occurring.