Answer: There are two chemicals registered for suppression of bermuda grass in tall fescue. They are fenoxaprop and fluazifop. Fenoxaprop goes under the name of Acclaim Extra. Fluazifop goes by the brand name Fusilade II or Ornamec. Both chemicals have been around for several years. Ornamec is the one I have seen used the most. Bermuda grass suppression is a fairly recent addition to the uses for these chemicals. The Ornamec label has changed within the past year to make it legal for bermuda grass suppression. This may be the reason I hear more homeowners talking about killing bermuda in a fescue lawn.
My initial impression is that both of these chemicals should not be used by homeowners unless they are experienced in sprayer calibration. The chemicals are not dangerous to apply, but have to be used precisely. Accidentally doubling the rate could create problems by killing or severely injuring the desirable grass. Given the precision that is needed, the chance for lawn injury, and the fact that this is relatively new, I wouldn't be surprised if it was difficult to find in any garden center or hardware store.
I still follow the "mow it when it is green" method of lawn management so I have never personally tried these chemicals. I haven't talked with any of our researchers who have used the chemicals either. I keep hoping for a chemical that would kill bermudagrass in one shot, but here are the standard recommendations for what we have now.
The recommendation for fenoxaprop is to use 20 fluid ounces per acre. This works out to .46 ounces per 1000 square feet. Spray once when the bermuda grass is first greening up. Bermudagrass is a warm season grass while tall fescue is a cool season grass. So when the bermudagrass first starts growing, the tall fescue is in mid- stride. That is the most vulnerable time for the bermudagrass. The second application should be made in fall, when bermuda grass is again active.
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