The pathogen that causes Take-All Root Rot, Gaeumannomyces graminis var. graminis is always present in our warm- season turf species. Any type of stress can trigger this disease. Prolonged periods of heavy rainfall also encourage its development. In South Florida, we see the disease during summer and into the fall, so you’ll want to take proactive measures now. Symptoms present themselves on the leaves in the form of irregular, light- colored patches and eventual death of the turf. Take-All Root Rot can also be detected through inspection of roots.
One the disease develops, it is extremely difficult to control. The best management option is to prevent this disease from developing. This includes cutting no shorter than University of
Florida- recommended, species-specific mowing heights, never removing more than 1/3 of the blade, and taking care not to overfertilize, overwater, or otherwise stress the turf. For management, we recommend using a fungicide that contains pyraclostrobin, myclobutanil, azoxystrobin, triadimefon, fenarimol, propiconazole, or thiophanate methyl. It is best to use these fungicides preventatively, about a month before we normally see symptoms,which is right now. After the disease has begun to develop, these fungicides can be used, but field trials haven’t been conclusive as to which, if any, are most effective.
To help the turf make up for lost nutrients being delivered to the blades, a combination of slow-release and foliar fertilization can be used.
More information is available:
- Take-All Root Rot, by Dr. M.L. Elliott and Dr. P.F. Harmon
- Take-all Root Rot (referred to as Bermudagrass Decline on bermudagrass) by Dr. M.L. Elliott
