First off, thank you to all who were able to attend Mizzou's Turf Field Day in Columbia on July 13th. Although it may be difficult to take off in mid-July, it was nice to see some MVGCSA representation. For those who were not able to make it this year, hopefully we will see you there next year. The weather was great and there was plenty of research focused specifically on golf course management. Any feedback or recommendations for next year would be appreciated.
As for local research in the St. Louis area, the collaborative project between MVGCSA and the University of Missouri began in early June of this year which focused on bermudagrass control in zoysia. After seven weeks, data recording bermuda injury and zoysia tolerance to the different treatments is beginning to show some trends. Six treatments (see table below) were selected from a greenhouse screening to be included in our research trial located at "The Falls" golf club in O'Fallon, MO where Rob Schaff is the superintendent. Of those six, three have shown to be very effective at suppressing the bermuda without causing significant injury to the zoysia. The most effective treatment so far has been treatment 3 (Fusilade (5.1 oz/acre) +Turflon Ester (28.5 oz/acre)) followed by treatments 1 and 2 (both rate combinations of Acclaim Extra + Turflon Ester). Treatment 3 was the most effective for controlling bermuda two weeks after the first application although treatments 1 and 2 appear to be equally effective after 4 weeks. After six weeks, it seems that the 'Fusilade' application (treatment 3) maintains a higher quality zoysia stand compared to all other treatments while still regulating the bermuda. Treatments 4 and 5, which combine Tenacity with Acclaim and Fusilade, have not provided consistent bermuda control and have caused significant stunting and injury to the zoysia.
Three applications have been made to this point with a reapplication interval of 21 days. Based on the bermuda regrowth threshold of 30%, the 21 day interval was appropriate earlier in the summer but since the temperatures and growth rates have increased, the next reapplication is scheduled for 14 days after the last. We would love to hear feedback from anyone else that is spraying these products or others to control bermuda in zoysia. Steve Song (M.S. candidate at MU) is establishing an additional field site at the turfgrass research facility in Columbia, MO to evaluate these and other treatment combinations and timings as well. Please contact Dan Lloyd, Rob Schaff, or Tim Roethler with questions or comments about this research.
Treatment | Trade names | Active ingredients | Application Rate (Oz Product/acre) | Reapplication interval |
1 | Acclaim + Turflon | Fenoxaprop + triclopyr | 28 +6.5 | 21 day |
2 | Acclaim + Turflon | Fenoxaprop + triclopyr | 24 +24 | 21 day |
3 | Fusilade + Turflon | Fluazifop + triclopyr | 5.1+28.5 | 21 day |
4 | Tenacity + Acclaim | Mesotrione + Fenoxaprop | 5+28 | 21 day |
5 | Tenacity + Fusilade | Mesotrione + fluazifop | 5+5.1 | 21 day |
6 | Untreated | - |
Photo taken 14 days after the first application
Tim Roethler and Rob Schaff discussing treatment effects
