The fungus Rhizoctonia solani, better known as Brown Patch, appears in area lawns about this time each year.

Brown Patch can affect a number of warm-season grasses.

Locally it is St. Augustine turf that is most frequently damaged by the fungal disease.

An article prepared by the Bexar County Extension Office indicates that the popular St. Augustine selection Raleigh is a favorite of the fungus.

Brown Patch can develop rapidly when conditions are warm and humid.

Daytime temperatures below 90 degrees and nighttime temperatures in the 60-degree range provide the perfect air temperature for fungal development.

Therefore, fall and spring are when we usually see Brown Patch problems in the Kingsville area.

The first symptom appears as a small circular, water soaked dark grass that soon wilts and turns yellow or brown.

As the fungus grows outward from the center, there is a grayish-black colored ring of wilted grass around the perimeter that is called a smoky ring.

The patch begins small, a few inches in diameter, and increases in size as the disease progresses.

In most cases the disease goes unnoticed until the yellow or brown area becomes sizable.

Another symptom is the leaves of the grass are easily pulled from the stolons.

The Brown Patch fungus attacks and destroys the tissue at the base of the leaf.

The good news being the stolons usually are not killed and the grass in the center of the patch may recover in a few weeks. New growth will appear during the recovery phase. All lawns are susceptible to Brown Patch, but lush, heavily fertilized and watered turf is more likely to suffer from Brown Patch than a less tended lawn.

Brown Patch can be controlled by applying a fungicide. There are numerous products on the market that are labeled for Brown Patch control.

Generally, fungicide should be applied at the first sign of infection in the fall.

Subsequent application can be made, according to the product directions, while weather conditions remain favorable.

Grass should be kept as dry as possible to slow the spread of the fungus.

It should be watered as little as possible and only in the early morning hours.

Avoiding excessive applications of nitrogen fertilizer will also help in reducing the development of this fungal disease that appears each fall and spring across South Texas.