Take-all root rot and bermudagrass decline
By Lane Tredway, Ph.D., technical services manager for Syngenta
Take-all root rot has become a common problem on ultradwarf bermudagrass putting greens in the transition zone. Patchy or ring-like symptoms typically appear in the late summer to fall as temperatures cool and days get shorter. Symptoms can also appear in the winter or early spring when the bermudagrass is growing slowly or in a semi-dormant state.
Photo: Lane Tredway, 2021
Curative control of take-all root rot is difficult for a couple of reasons:
- Bermudagrass doesn’t grow aggressively this time of year and can be slow to recover from any damage.
- Take-all root rot pathogens do most of their damage in the summer when soil temperatures are warm. They are not growing actively in the fall, winter and spring when take-all root rot symptoms are most evident.
So, how do you cure a disease when the pathogen isn’t active and the turf isn’t growing? The short answer is, you can’t — but you can take steps to protect turf from other stresses and facilitate recovery once favorable growing conditions return.
Making appropriate applications
Tank mixtures of Appear® II fungicide (6 fl. oz./1,000 ft.2) with either Daconil® Action™ fungicide (3.5 fl. oz./1,000 ft.2) or Secure® Action fungicide (0.5 fl. oz./1,000 ft.2) on a 14-day interval are most helpful when take-all root rot symptoms break through. These tank mixtures work by:
- Protecting weakened bermudagrass from a broad range of pathogens and abiotic stresses, helping to prevent further decline
- Providing bermudagrass greens with faster, more uniform spring green-up, which can equate to a faster recovery from take-all root rot
Once bermudagrass growth resumes in spring, consider an application of Briskway® fungicide to further facilitate recovery from take-all root rot. Its DMI + QoI combination delivers excellent activity on the take-all root rot pathogens without the growth regulation that comes with some other DMI-containing products. Briskway can now be applied at curative rates of 0.9 to 1.2 fl. oz./1,000 ft.2, which shows improved activity against take-all root rot and other diseases including fairy ring and mini ring.
Preventive applications should be initiated in late summer to fall when soil temperatures decline below 80° F. To help optimize application timing, sign up for Soil Temperature Alerts to receive an email notice when soil temperatures reach the right thresholds in your area.
To prevent take-all root rot this summer, consider the GreenTrust® 365 Spring Dead Spot and Take-all Root Rot Assurance Program, which recommends a combination of Briskway, Posterity® Forte and Headway® fungicides coupled with performance guarantees for managing these destructive diseases.
For more information on treating take-all root rot, contact your local Syngenta territory manager.
© 2022 Syngenta. Important: Always read and follow label instructions. Some products may not be registered for sale or use in all states or counties and/or may have state-specific use requirements. Please check with your local extension service to ensure registration and proper use. Action™, Appear®, Briskway®, Daconil®, GreenTrust®, Headway®, Posterity® and the Syngenta logo are trademarks of a Syngenta Group Company. Secure® is a registered trademark of Ishihara Sangyo Kaisha, LTD. All other trademarks are property of their respective owners.