Plant Pathology Infobytes

September 18, 1998
Look Out for Brown Patch In The Home Lawn

Are circular patches of brown grass showing up in your lawn? Several things could be responsible for this condition, but it's likely that you're seeing the effects of brown patch. Brown patch is a fungus disease which frequently makes its appearance on St. Augustine, zoysia, and centipede grasses during later summer and early fall.

Brown patch can develop anytime during the growing season but is most common and troublesome in lawn areas where the disease has been a problem in past seasons. Another factor which contributes to disease development is several days of rainfall and cool nighttime temperatures in the 50-60 degree range. While most areas of the state have been on the dry side, chances are the weather will change during the coming weeks.

Brown patch tends to be most severe in lawns fertilized heavily with nitrogen fertilizer earlier in the season. Grass in these lawns tends to be lush and remain green longer into the season. These conditions makes turf grass more vulnerable to attack by the brown spot fungus.

How can you tell if brown patch is present in your turf? This disease is characterized by the development of irregular, circular areas. Grass in affected areas loses its normal green appearance and develops a straw-brown color. Affected areas range in size from a few inches to several feet in diameter. Generally, brown patch attacks only the leaves and stems of the grass. However, if not controlled it can attack the roots and kill large areas of the lawn.

Homeowners who've spotted brown patch in their St. Augustine, zoysia, or centipede lawns may want to apply a fungicide to slow disease development and increase chances of stronger turf as we approach the winter season.

For best results, the fungicide should be applied early in later summer or early fall before brown patch becomes widespread over the lawn. Concentrate on areas where this disease has been prevalent in the past. Several applications of fungicide may be necessary. Be sure to follow fungicide label instructions concerning application rates and timing.

Next spring, plan to begin a brown patch fungicide application program early in the season. Also, you'll want to check with the County Extension Office about other practices which should be included in a season long disease control program for brown patch.


Written by the late Dr. Frank Killebrew

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