How to remove bermudagrass from St. Augustinegrass with Recognition
By Lane Tredway, Ph.D., technical services manager, Syngenta
The inability to control bermudagrass infestations in St. Augustinegrass turf has been a major challenge for lawn care operators (LCOs). A solution for bermudagrass control has remained elusive — until now.
Recognition® herbicide is the latest Syngenta herbicide formulation that contains trifloxysulfuron, the active ingredient in Monument® 75WG herbicide, with a proprietary herbicide safener called metcamifen. Recognition was developed to provide LCOs with a much-needed option to control sedges, broadleaves and grass weeds in St. Augustinegrass turf.
Recognition alone does not control bermudagrass, but when tank mixed with Fusilade® II herbicide at rates up to 24 fl. oz./A, the combination controls bermudagrass without injuring St. Augustinegrass. How is this possible? The safener in Recognition, metcamifen, triggers certain grass species to tolerate certain herbicides, like Fusilade II, without impacting its activity on weed species like bermudagrass.
To control bermudagrass out of established St. Augustinegrass turf:
- Apply Recognition (1.29 oz./A) with Fusilade II at 24 fl. oz./A
- While 12-24 fl. oz./A of Fusilade II can be used, we recommend 24 fl. oz./A for greatest efficacy
- Include a non-ionic surfactant at 0.25% v/v or 0.32 fl. oz./gal. of spray solution
- Use typical spray volumes from 20-80 gal. of water/A
- Use flat-fan nozzles that produce medium-to-coarse droplets to ensure uniform foliar coverage
- Provide adequate fertility and irrigation to encourage St. Augustinegrass growth and spread
Depending on the amount of bermudagrass present and how well-established it is, additional applications of Recognition + Fusilade II may be necessary to maintain bermudagrass control until the St. Augustinegrass can spread into the voids left behind. Application intervals vary by time of year and growing conditions, but typically are four weeks for 12-18 fl. oz./A of Fusilade II or five to six weeks for 24 fl. oz./A of Fusilade II. The active ingredient in Fusilade II is foliarly absorbed, so it is best to apply once the bermudagrass begins to regrow in treated areas.
The 24 fl. oz./A rate of Fusilade II also provides excellent control of Poa annua, goosegrass and dallisgrass.
For more information, including data, the label, the 2(ee) and more, visit GreenCastOnline.com/Recognition.
Exercise caution when applying Recognition around desirable cool-season grasses. Recognition can move with runoff water, equipment and foot traffic.
Always refer to the product label for full use recommendations.
© 2023 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. Syngenta supports a FIFRA Section 2(ee) recommendation for tank mixing Recognition and Fusilade II to remove bermudagrass from zoysiagrass and St. Augustinegrass. Syngenta also supports a FIFRA Section 2(ee) recommendation for tank mixing Recognition and Triclopyr to control weeds. Please see the Section 2(ee) recommendation to confirm that the recommendation is applicable in your state. The Section 2(ee) recommendation for tank mixtures with Recognition should be in the possession of the user at the time of application. Fusilade®, GreenCast®, Monument®, Recognition® and the Syngenta logo are trademarks of a Syngenta Group Company. All other trademarks are property of their respective third-party owners.