Dead Patches in Lawns

Sod Webworm

• Dead patches in lawns can be caused by pests such as the sod webworm. According to the Ohio State University Extension, this pest is highly destructive to lawns, cemeteries, golf courses and parks. Damage first appears during the spring and begins as small patches of dead grass. By the late summer, these patches have caused the grass to become thin, and the dead patches are larger. Sod webworms prefer perennial ryegrass, Kentucky bluegrass and fine fescues. Look for this pest in patches of brown, dead grass by parting the grass blades with your fingers. Search for green pellets, which are excreted by sod webworm larvae. Sod webworms are cream-colored and 3/4-inch long. The larvae usually feed on grass in the late fall months and early spring.

Spring Dead Spot

• According to the University of Arkansas Division of Agriculture, spring dead spot disease, or SDS, is common in Bermuda grass. This disease is caused by the fungus Leptosphaeria korrae and most commonly appears in the early spring, although the infection actually occurred the previous fall. The symptoms associated with SDS include well-defined patches of dead grass, which get larger with each passing year. Dead patches can exceed 3 feet in diameter, and patches have a sunken appearance. Grass that is less than three years old is less susceptible to developing this fungal disease. Using a fungicide specially developed for spring dead spot disease can help eliminate and control the disease.

Dollar Spot Disease

• Dollar spot disease affects turfgrass, causing dead patches to form in lawns. According to the Colorado State University Extension, dollar spot disease received its name for the silver dollar--sized dead patches it causes in lawns. Dollar spot disease is caused by lanzia and moellerodiscus, which commonly affect Kentucky bluegrass, Bermuda grass, fine fescues and perennial ryegrass. Dollar spot begins as yellow spots that turn white or light tan. The affected grass begins to die, and lesions form on the grass. Strands of fungus are often visible on affected lawns in the early morning hours when dew is still on the grass. Stress from drought, improper mowing and low nitrogen levels all can make grass more susceptible to dollar spot disease. Spraying the lawn with fungicides should only be used as a last resort and in lawns where the disease is recurring.