Native to North America and originating from the western Great Plains, buffalo grass is a warm-season perennial turf grass that tolerates drought and heat. Buffalo grass is low-growing and needs little water to thrive, spreading by above-ground stems called stolons. Buffalo grass is fairly resistant to most common lawn diseases.
Summer patch is a disease caused by the fungus Magnaporthe poae that typically infects buffalo grass lawns when temperatures are hot, usually 85 to 95 degrees Fahrenheit. Appearing in late spring, summer patch causes circular yellow to tan areas of dying or dead grass that can be up to 12 inches in diameter. The spots may have healthy, green grass in the center. You can prevent summer patch in buffalo grass lawns by aerating the lawn to improve drainage and reduce soil compaction, as well as by feeding the lawn with a slow-release nitrogen fertilizer, dethatching the lawn and avoiding mowing too low. If your buffalo grass is severely infected with summer patch, you can apply an appropriate systemic fungicide in autumn.
Like summer patch, brown patch infects buffalo grass lawns when temperatures are hot, usually 80 to 95 degrees. Brown patch, also called Rhizoctonia blight, is caused by the fungus Rhizoctonia solani and creates irregular brown patches in the lawn that enlarge to several feet in diameter. The grass blades and sheaths often have a water-soaked appearance, wilt, turn brown and die. Buffalo grass lawns that have thick thatch layers, are over-fertilized with nitrogen and are in warm, humid, inland regions are the most susceptible to brown patch disease. Treat brown patch by aerating the lawn to improve drainage, avoiding over-watering the grass, de-thatching the lawn and cutting back on or eliminating fertilizing the lawn with nitrogen. You can apply an appropriate fungicide to the buffalo grass lawn, if the brown patch disease is widespread in the lawn or if the grass is newly seeded or sodded.
Helminthosporium leaf spot disease causes small brownish-black spots on the buffalo grass's blades. The spots enlarge and develop tan centers with purplish-black edges. The disease can progress to a "melting out" phase, where the crowns and stolons will turn brown and the grass will die. Leaf spot disease occurs in cooler, rainy or moist spring weather. Treat leaf spot disease by avoiding over-fertilization of the buffalo grass, waiting to feed the lawn until temperatures warm in the summer and avoiding fall fertilization. Don't water the buffalo grass lawn in the evening, because the wet grass will the spread of the disease. For leaf spot infections that have progressed into the "melting out" stage, apply an appropriate fungicide to your buffalo grass lawn. Otherwise, the disease will abate as soon as temperatures warm and conditions become drier.