How to Get Rid of Brown Patch Grass Fungus

Instructions

Eradicating brown patch disease may not require all of the following steps. You can stop work when the efforts show results. The time and effort required will depend entirely on the severity and persistence of the infestation—minor problems may be very easy to solve, while combatting widespread infestation can be a year-long endeavor. Always try to control brown patch fungus by adjusting cultural practices before reaching for chemical fungicides.

1. Diagnose the Disease

   Brown patch appears as irregular circular patches in the lawn that are brownish-yellow in color and range from 6 inches to several feet in diameter. The affected leaves usually remain upright, and close inspection shows lesions on the leaves that are tan in color and irregular in shape with a dark brown border. White, cottony, mycelium can be found on dew-covered turf in the early part of the morning.

   The ring itself is most visible in the morning. Sometimes grass within the ring is entirely killed, creating a sunken look to the patch, but more often the grass inside the patch simply becomes thinner than the surrounding lawn.

2. Improve Air Circulation

   Many cases of brown patch can be cured simply by improving air circulation in the lawn, which reduces the humidity that favors the fungus. The best way to do this is to aerate and dethatch the lawn annually.

   Dethatching can be done manually, with a stiff bow rake or dethatching rake, or with power equipment available for lease at home centers and tool rental outlets. Aeration is normally done with a power rental tool, or by a hired professional lawn service.
   

3. Change Cultural Practices

   Brown patch fungus thrives in wet, fertile conditions, so the response to ongoing lawn problems is to reduce feeding of your lawn and make sure watering practices are appropriate.

   Avoid feeding your lawn during hot and humid weather, and reduce the amounts of fertilizer used. Fertilizer manufacturers often recommend repeated heavy feedings, but your lawn is often healthier with just one or two light feedings each year.

   Watering is probably not necessary at all if you are getting 1 inch of rainfall per week, But if you do water, do it early in the day so the grass can dry out fully before nightfall. If dew is collecting on your lawn each morning, your lawn probably does not need to be irrigated at all. Standing dew can be removed by dragging a water hose over the lawn, which will lower the humidity that causes brown patch disease.

4. Apply Fungicide

   Lawn care experts say that fungicide treatment is appropriate only for high-value ryegrass and bentgrass turf blends; most lawns typically recover without chemical treatments.

   The first spray of fungicide should be applied immediately after the symptoms first appear, especially if hot and humid weather is expected. Although fungicides can be purchased by homeowners, it's best to deal with a lawn care company staffed by professionals who are trained to diagnose and treat lawn diseases.

   As this any chemical application, it's best to spot-treat diseased areas rather than apply chemicals broadly over the entire lawn.
   

5. Reseed With Resistant Grass Varieties

   Where all other efforts fail you may need to reseed with a turfgrass variety that has known resistance to this fungus. A variety of grasses are available with moderate resistance to the Rhizoctonia fungus. If a brown patch is an annual occurrence, consider top-seeding your lawn with resistant grasses. Check with your local university extension service on recommendations for resistant grass species.