Diagnosing Brown Patch in Hybrid Bermuda Near Driveway Runoff

Identifying Brown Patch Fungus

A homeowner had 4x5 ft brown blotches in hybrid Bermuda near a driveway (vehicle wash/rain runoff) plus random smaller spots. The expert provided a field diagnostic test.

Pull Test for Brown Patch

• Grab affected blades, tug gently.
• If blades pull up easily with no roots attached: Likely brown patch (Rhizoctonia fungus).
• If roots hold: Consider other causes (chemical, mechanical, dog urine).

Treatment Options

• Commercial fungicide: Labeled for brown patch/Rhizoctonia.
• Baking soda drench: Dissolve in water, spray affected area + surrounding soil. Expert prefers this—effective, non-toxic to beneficial insects.
• Whole-yard treatment: If one area has it, spores likely elsewhere. Preventive application wise.

Investigating the Driveway Runoff Factor

• Car wash soaps, waxes, cleaners may contain chemicals toxic to grass.
• Test: Move car washing away from lawn. If spots stop expanding, product is culprit.
• Switch to grass-safe, biodegradable car wash products.

Cultural Prevention

• Water deeply, infrequently (morning only).
• Mow at correct height for hybrid Bermuda (0.5-1.5 inches).
• Avoid excess nitrogen in hot, humid weather.
• Core aerate annually to improve drainage/aeration.