Take-all disease is a common fungi disease that attacks St. Augustinegrass, centipedegrass, and zoysiagrass. The fungus grows along the length of the outside of roots, stolons, and rhizomes. The hyphal strands are dark and form thick runners. As long as the turfgrass stays healthy, the fungus remains on the outside of the plant without much damage. However, when the plant becomes stressed for any reason, its defenses become weakened, and it no longer repel the fungus.
Once the fungus enters the plant, the fungus absorbs the supporting tissue of the plant. Affected tissue turn yellow first then dark brown or black, depending on the stage of infection. Roots, crowns, stolons, and rhizomes all may be infected. Symptoms are most common in the summer and fall.
Since the fungus causing Take-All Disease does not become problematic until the turfgrass falls under stress, eliminating stress on the turf plants is an important part of turf recovery. Take a complete survey of all cultural practices that cause stress and change any practices that are not best for the turf.
Common stress factors
Improper mowing frequency and height for the turfgrass variety
Fertility (too much or too little depending on the turf type)
Use of herbicides (most warm season grasses are sensitive to herbicides used for weed control.
Poor watering practices
Get a soil test as a first stage analysis. This should include the top 4" where most of the turfgrass plant lives. This will tell you the soil's pH levels and fertility. Fungicides do not work against this disease.