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Flowers, Fruits, and Frass

Brown spots in the lawn

Many who have been seeking out the McLean County Master Gardener help desk have been complaining of brown patches in the lawn. Unfortunately, most lawn ailments present themselves as unsightly browning in a sea of lush green. The following are some of the potential culprits.

If the grass is brown across the entire lawn, your lawn mower blade may have becomes dull and ripping the grass tips causing them to brown.

If the grass is brown and wilted, then it just may need to be watered.

If the grass is brown and the blades look like they have been chewed off, then sod webworm may be the issue. Sod webworm are starting to become more prevalent around the state because they thrive in hot and dry weather. Examine the grass for silken burrows enclosing dull colored larvae that rest during the day and cause havoc in the night. Sarah Hughson, Extension specialist in Entomology, suggests biological treatments to control the larvae population including Spinosad, Steinernema carpocapsae and entomopathogenic nematodes. Sod webworm larvae and damage pictured.

If the grass is brown and the blades look like they have been chewed off and you live in an agriculture setting, then army webworm may be the issue. Armyworms usually do not become an issue for lawns until late summer where the caterpillars hide out during the day and feast at night. When they are small, they are dark in color but as they grow, they develop five orange stripes. They are egregious eaters and the damage seems like it can happen overnight. Drenching grass with a soapy solution will cause caterpillars to come the surface. Phil Nixon, former Extension specialist in Entomology, says treatment is warranted if there are two or three caterpillars per square foot. The same treatment for sod webworm will be effective on armyworm. Army webworm pictured

If the grass is  brown and there are lesions on the individual leaf blades that is tan with a dark jagged margin then it may be Brown Patch. Brown patch is a disease that attacks cool season grasses and presents when the weather is humid with high temperatures. A gardener can observe the white mycelium growth early in the morning. Travis Cleveland, Extension specialist, suggests removing dead grass and reseeding, avoid fertilizer treatment, and water in early morning. Contacting professional lawn service may be warranted if problem is severe.

If grass is brown and roots are missing, it may be grub damage. The most common grubs for our area are Japanese beetles, May and June beetles. It is important to treat these pests when the adults are flying around and laying eggs and not in the spring. Grubs are easy to find under the sod and are white and c shaped. Please visit Lawn talk from the University of Illinois Extension for treatment options.

If grass is brown and sporadic, it may be pet damage. Watering the area after pets urinate may be prevent future damage.