University of Maryland Extension

Summer Patch - Lawns

straw colored patches in lawn
Summer patch causes circular straw-colored patches of grass during the summer

Susceptible Grasses

· The most commonly infected grasses are Kentucky bluegrass and fine leaf fescue.

Primary symptoms

· Initial symptoms on Kentucky bluegrass are roughly circular straw-colored patches of turf that may resemble another turf disease called dollar spot. These patches continue to enlarge with outer edges taking on a yellow or bronzed appearance. The leaf blades turn brown from the tip giving the turf a straw colored appearance. Healthy turf may survive in the middle of the patches giving a doughnut or frog eye effect. Circular depressions within the patches, called crater pits, may also be present.
· Fine fescue grasses develop orange or bronze colored patches prior to the straw color.

Season

· This disease usually appears in late June or early July when temperatures above 90F occur.

Environmental Conditions

· This disease is always more severe in the full sun.
· Daytime temperatures of 90F and soil temperatures of 78F coupled with moisture predispose susceptible turf to this disease.

Management

· Select resistant cultivars when establishing turfgrass.
· Avoid over-fertilization of turf, especially in the spring.
· Mow at the highest recommended height.
· Avoid light frequent irrigations.
· Reduce thatch when it exceeds a ½ inch in thickness.

Maintained by the IET Department of the College of Agriculture and Natural Resources. © 2020. Web Accessibility

University programs, activities, and facilities are available to all without regard to race, color, sex, gender identity or expression, sexual orientation, marital status, age, national origin, political affiliation, physical or mental disability, religion, protected veteran status, genetic information, personal appearance, or any other legally protected class. If you need a reasonable accommodation to participate in any event or activity, please contact your local University of Maryland Extension Office.