Symptoms. Roughly circular patches or crescent shaped streaks of plants first become darker green than the surrounding turf. Then the plants wilt. White spots may appear on the leaves, usually as bands across the leaf. The leaves then collapse quickly, turn brown, and die.

Patches can be 3 feet across and often grow together to form irregularly shaped areas. Often the center of the patch will not be affected, giving the patch a doughnut-like appearance, sometimes called a "frog-eye". The edges of the patches may blend into the surrounding healthy turf or may be very distinct. The edges may also be reddish-brown. The affected areas may be completely blighted or may have healthy plants mixed in with the dead ones.

When the plants are dug up, the roots are dark brown to black, hard and dry-rotted. On the surface of the roots and crowns, a dark brown network of fungal growth can sometimes be seen.

Similar Diseases.  The symptoms are similar to Brown patch, but the "smoke ring" often seen in that disease is lacking.

Prevention.

• Mow at the recommended height, mowing lower can stress the plants and predispose them to this disease.
• Remove thatch if it is deeper than 3/4".
• Keep the pH of the thatch and the soil at 6 to 7 by adding small amounts of lime or sulfur regularly.
• Apply balanced fertilizers and avoid deficiencies of phosphorous and potassium.
• Avoid excessive nitrogen, especially in spring and summer.
• Water as deeply and infrequently as possible.
• Water in the early part of the day to allow leaves to dry thoroughly.

Resistance is available to this disease. See current recommendations for chemical control measures.

By Pamela S. Mercure, IPM Program Assistant, University of Connecticut, 1998.

References.

Smiley, R.W. 1983. Compendium of Turfgrass Diseases. APS Press, St Paul, MN.
Smith, J.D., N. Jackson, and A.R. Woolhouse. 1989. Fungal Diseases of Amenity Turfgrasses, Third Edition. E. & F.N. Spon, London.
Turgeon, A.J. 1996. Turfgrass Management, Fourth Edition. Prentice Hall, Upper Saddle River, New Jersey.

This information was developed for conditions in the Northeast. Use in other geographical areas may be inappropriate.

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