| what is TAKE ALL ROOT rot that affects st. augustine grass? |
| Take-all patch is a serious root rot disease caused by the soil-borne fungus. It was first discovered on St. Augustine grass in 1991 but has also been found in Bermudagrass, zoysia and centipede grass. Early symptoms appear as chlorosis (yellowing) and thinning turf in circular or irregular patches. The roots are often short, blackened and rotten. The grass stems, or stolons, can often be lifted from the soil due to the poor root system. The yellowing grass blades eventually die and become brown, followed by stolon death. The base of the brown patch infected blade is usually slimy and rotten. The key difference is that the stolons remain green with brown patch allowing the grass to recover in the spring. Grass usually creates a donut look as it regreens. The most effective way to control these diseases is through a combination of both cultural and chemical practices. Good surface and subsurface drainage is important. Low areas in lawns that remain under water after heavy rains are highly susceptible to these diseases. Simply changing your irrigation practices can help. Rake your lawn to remove diseased grass blades and accumulated thatch as soon as you see the early signs of dying grass. This allows for greater air circulation and reduces the humidity at the soil level that promotes fungal growth. It also loosens the soil surface and allows for better penetration of chemicals. Fungicide applications should be considered where take-all root rot is present. Fall applications as symptoms first appear have proven to slow the fungus. Fungicides that are labeled for control of these diseases or that have shown promise include: Banner Maxx, and Heritage. Waiting until you have large areas of fungal outbreaks is too late to use the fungicide approach for control. Follow directions when applying any chemical. Note that these products should not be applied during high temperatures. Fungicides should be applied in a high volume of water so the fungicide dries on the leaves and can move down into the root zone. Making two or three applications at three-to-four week intervals may also increase effectiveness. |
