Transition from Rye Grass to Bermuda

The transition from bermudagrass reseeded with rye grass to bermudagrass requires the use of specific herbicides for this task, in addition to the soil temperature should be above 10°C and the leaf temperature above 15°C.

If herbicides are not used at the time of transition, this will result in rye grass patches on bermudagrass that have gone through a series of physiological processes of summer stress resistance that result in reduced treatment efficiency.

Successful bermudagrass cover requires at least 100 days without competition from rye grass in order to develop optimally. Therefore the growth potential The different locations have to be taken into account for the summer recovery and the programming of the following autumn reseeding.

The recommended herbicides are as follows:

1. Sulfosulfuron, several applications may be necessary for success, repeat applications should always be made when temperatures are above 27°C.
2. Flazasulfuron, use when at least one 50% greening exists.
3. Pronamide, very slow but very effective, can delay greening.
4. Metsulfuron, several applications are needed for effectiveness.
5. Trifloxysulfuron-sodium, low dose uses for gradual transition and high dose with high temperatures for rapid transition.
6. Foramsulfuron, repeated application at 4-6 weeks for maximum efficacy, higher doses require high temperatures.
7. Rimsulfuron, several applications are necessary for its effectiveness.

Greg Breeden, James T. Brosnan, Thomas J. Samples Department of Plant Science University of Tennessee.

A slightly later treatment at a lower dose is more advisable than an earlier treatment at a higher dose, as this results in less damage to the bermudagrass and quicker recovery.

Studies from the University of Arizona, Phoenix indicate that treatments with foramsulfuron, flazasulfuron and tryfloxysulfuron from May onwards reduced the quality of rye grass and their elimination was complete by July, and poa control was total with foramsulfuron, while tryfloxysulfuron achieved 88% control of poa. On the negative side, these herbicides resulted in areas of bermudagrass damage. However, the Pronamide treatment was less effective on rye grass and poa annua but with less damage to bermuda recovery.