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Conditions right for brown patch
The Coast Gardener Newspaper and Web Column - May 4, 2002

Brown patch, caused by the fungus Rhizoctonia solani, is a common disease that likes to become quite active in springtime. With warm, sunny days and cool nights, this disease flourishes each spring and will reappear if conditions are right in the fall. Several cases have been confirmed in area lawns over the past few weeks.

This disease is prevalent in St. Augustinegrass and centipedegrass during most years. Thankfully, brown patch is easier to treat than the dreaded fungal disease called "Take-all." Grass tends to recover faster and easier from brown patch, too.

This disease is characterized by the development of irregular, circular areas a few inches to several feet in diameter. These areas will usually appear as brownish to grayish patches. These water-soaked or scalded spots in the lawn spread rapidly, becoming large, brown areas. Generally, brown patch fungus attacks the base of leaf sheaths where they are joined to stolons (runners). Leaves turn yellow in St. Augustinegrass and a reddish color in centipedegrass. If left untreated, large areas of turfgrass can die.

There are several factors that tend to make grass more susceptible to brown patch. Excessive applications of nitrogen fertilizer promote a lush growth of grass that is readily attacked. Watering late in the evening or at night allows grass to remain wet for long periods of time. Wet conditions create a perfect environment for the fungus to flourish. Thatch is a buildup of partially decomposed leaves, stems and roots that promotes excessive disease development as well.

What can you do to keep brown patch out of your yard? Prevention is the best defense against this disease:

If proactive efforts are still not enough, a fungicide treatment will be necessary for effective control. Some products available include Heritage, Bayleton, Terraclor and Strike. Regardless of the fungicide you choose, carefully read and follow label directions. Make certain that the product is labeled for your particular turfgrass and is an approved fungicide for brown patch control. Using the wrong pesticide can kill your grass and harm the environment when used improperly.

Scout your lawns now for signs of brown patch. Begin treatment early to avoid large areas of dead grass that will likely fill with weeds later this year.

These archived gardening columns were written by Chance McDavid, former Harrison County Extension Agent.