University of Maryland Extension

Summer Patch - Lawns

straw colored patches in lawn

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

Grasses Affected:

· 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.

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