Steps For Renovating Toxic KY-31 Fescue To Novel-Endophyte Fescue
DR. JOHN JENNINGS
LITTLE ROCK, ARK.
Tall fescue is grown on approximately 2 million acres in Arkansas and is the most common perennial cool-season grass. Most of the fescue is the variety KY-31, and it is infected with the toxic endophyte that causes fescue toxicosis in livestock. Typical symptoms include rough hair coat, standing in ponds especially in cool weather, lameness in the hind feet during winter, loss of tail switch or rear hoof, panting or salivating in warm weather, low percentage calf crop and low weaning weights.
In cases where fescue toxicosis and fescue foot have occurred in the past, consider renovating toxic KY-31 fescue pastures and converting to a nontoxic novel endophyte fescue. There is no need to convert all KY-31 fescue. Dr. Ken Coffey’s research showed that converting just 25 percent of the fescue acreage to novel endophyte fescue was enough to offset many of the economic problems caused by toxic fescue.
Renovation Strategy
Use the spray-smother-spray technique to convert fescue pastures. Tillage by itself will not kill all the KY-31 fescue. The “spray-smother-spray” method has been a reliable method for renovating toxic fescue pastures and can begin in the spring or fall.
If starting renovation in the spring, starting late April to early May when fescue is actively growing and before any new seed is produced. Clip or graze the fescue to a height of 4 to 6 inches and apply a nonselective herbicide such as glyphosate at 2 quarts per acre. Depending on weather and how many weed seedlings germinate, a second herbicide application may be needed before the next step.
After the fescue top growth dies down, no-till plant a summer-annual forage, such as pearl millet or sorghum-sudan. The summer annual forage provides heavy shade and competition for any remaining fescue plants and can be harvested for hay or grazed.
In fall, after harvest of the summer annual, apply herbicide again to kill any remaining KY-31 fescue and the summer annual forage. The field can be planted with novel endophyte fescue in the fall.
If starting the renovation process in fall, apply glyphosate to the actively growing fescue during fall (September to late October) and no-till drill a small grain for winter/spring forage. Do not plant annual ryegrass because natural reseeding from ryegrass will cause severe competition later when novel endophyte fescue is planted.
Follow the harvest of the small grain forage in late spring with a second herbicide application. Continue the renovation process by no-till drilling a summer annual such as pearl millet. After the final harvest of the summer forage, no-till drill the novel-endophyte fescue in fall.
Several proven novel endophyte fescue varieties are on the market and have been grown successfully in Arkansas. Current varieties include MaxQ and MaxQ-Texoma (PenningtonInc.), Estancia (Mountain View Seeds), BarOptima (Barenbrug Seed) and Duramax (DLF International). The technology has been shown to work in research and on farms and should be considered as part of a strong forage program. ∆
DR. JOHN JENNINGS: Professor, Extension Forage, University of Arkansas