Take-All Root Rot
This fungal disease attacks St. Augustine and Bermuda lawns
Take-all patch, caused by the fungus Gaeumannomyces graminis var. graminis, is a serious disease of St. Augustine and Bermuda turfgrass. It can also infect Zoysia, Fescue, Perennial Rye. The disease is most active in the fall through spring, when temperatures are more moderate and rainfall and humidity are higher. If this disease is left to spread un-checked, it can kill large sections of your lawn.
You'll see discolored leaf blades, which yellow at first and then fade to dead brown aeas. The size of the infection can range from several inches across to several feet across in an irregular pattern. The disease is often mis-diagnosed as an iron deficiency or chinch bug damage.
Frequent shallow watering is a big cause of this fungal disease, especially in compacted soils. The disease is spread from lawn to lawn by lawnmowers and other maintenance equipment. Soil aeration, oganic compost application, bio-fungicides and reducing irrigation water are the best natural ways to control this disease.