Take-all Root Rot, Whether You Like It Or Not!
If you have had issues with declining turf during the summer and early fall, it could be take-all! Take-all root rot loves to come out to play in the hot, wet Florida summers and early fall. Take-all root rot is a disease that is naturally present on the roots of warm season turf, so that means it is probably chillin’ in your Florida yard right now. Just because the disease pathogen is present in your yard does NOT mean that the disease can hurt your turf. In fact, 3 things must be satisfied in order for a disease to be an issue – we call this the disease triangle. By manipulating any 1 of the 3 elements of the disease triangle, the disease can be managed. You have more control over diseases than you realize. It is super nerdy cool when you embrace the disease triangle and use it to prevent many diseases!
Diseases are an issue in plants when there is a susceptible host, a disease present, and a conducive environment for the disease to thrive. In the case of take-all, warm season turf is a susceptible host. Take-all is the disease present. That leaves us with the environment. Take-all prefers high rainfall and stressed turfgrass. Managing the environment is the BEST option for managing the take-all root rot disease and preventing it from coming out to play in your turf. We also have some chemical controls, but they need to be applied preventively and are not as effective as managing a healthy turfgrass environment, plus, they can be $$$pency!
Signs and Symptoms
Take-all root rot is a disease present on the roots of turfgrass. By the time you notice irregular yellow and light green patches ranging in diameter from a few inches to a few feet, the disease has already been hurting the roots for a few weeks. Meanwhile, below ground the roots are getting short, black, and rotted. Stolons, and rhizomes may show black lesions when the disease is extra gnarly, which can lead to naked patches of soil.
HOT TIP! Insect damage during the summer could be confused with disease. Do not just assume insect or disease – IDENTIFY THE ISSUE! Then select the treatment plan. It is a waste of time, money, and chemicals if you make an application for disease control when you actually have hungry hungry chinch bugs. My favorite insect scouting tools are a dust buster and a white tray to tap the turf contents onto for easier inspection.
Treating the Disease
Treating the take-all root rot disease is focused on prevention. If you have all 3 disease triangle conditions satisfied for disease development in your yard and take-all does it’s thing, go ahead and mark your calendar next year one month ahead of when you observed the disease. Continue with monthly applications until the weather and environmental conditions no longer favor disease development (so when things start to dry out and cool off again). The disease is hard to control once you see those aboveground symptoms.
Preventive fungicide options include azoxystrobin, myclobutanil, propiconazole, pyraclostrobin, thiophanate methyl, and triadimefon. It is beneficial to lightly water in these fungicides immediately following the application.
Preventing the Disease
An ounce of prevention is worth a pound of cure, maybe even worth a few pounds of cure in the case of take-all root rot. Prevention is focused on limiting stress to the turfgrass and it is not hard to do!
- Mow at proper height for your turfgrass
- Bahiagrass = 3 – 4”
- Bermudagrass = 0.5 – 1.5”
- Centipedegrass = 1.5 – 2”
- Augustinegrass = 2.5 – 4”
- Zoysiagrass = 1 – 2”
- Mow regularly so that not more than 1/3 of the leaf blade is removed at a time
- Balance Nitrogen and Potassium applications at a 1:1 ratio of N:K
- Consider extra Potassium applications in late summer and early fall
- Do not apply lime to the turfgrass
- Augustinegrass is sensitive to herbicides even when following label requirements. Prevent weeds with a calibrated irrigation system and a by maintaining a dense stand of turf that is properly fertilized.
Further resources about take-all root rot: https://edis.ifas.ufl.edu/publication/LH079