Tall fescue is a cool season perennial grass that is well adapted to much of eastern Oklahoma. When managed properly, tall fescue can provide fall forage production that reduces the need for hay feeding, and spring grazing prior to the growth of warm season grasses. Tall fescue can be grown in mixture with bermudagrass, but care is needed to balance the competition between these species. Fall (September) application of 50 lbs. N per acre or more, followed by stockpiling, and reduced spring grazing will encourage tall fescue, while heavy spring grazing, followed by application of nitrogen in late spring and summer will favor bermudagrass.

Endophyte Infected Tall Fescue:
Tall fescue can contain a fungus inside the plant, known as an endophyte. Lab tests are needed to confirm the presence of the endophyte; the plant shows no visible symptoms of infection. The tall fescue endophyte is spread only through the seed, and can be eliminated from the seed by heat and humidity. The endophyte benefits the plant by increasing tolerance to stresses such as drought, insects, nematodes, diseases, etc. Most of the tall fescue in the USA is infected with a 'wild type' endophyte, which leads to decreased weight gain, reproductive problems, and often poor health for grazing livestock. Alkaloid compounds are produced that restrict blood flow, resulting in animals having a low grade fever. In warm conditions animals will seek shade, wade in water, and spend less time grazing. In cold conditions, the poor circulation can cause animals to be lame, and in severe cases lose tails and hooves. Unless a pasture was planted using tall fescue seed that did not contain the wild type endophyte, or the pasture has tested negative for endophyte, farmers and ranchers in eastern Oklahoma should assume that their pastures are highly infected with endophyte. Most tall fescue in Oklahoma is the cultivar Kentucky 31, which is endophyte infected (E+), unless treated to remove the endophyte.

What can a farmer do about the endophyte?
Some options are listed below.

1. Remove or don't plant tall fescue. A problem with this solution is that it removes one more option for fall to spring grazing in eastern Oklahoma.

2. Dilute tall fescue with a legume or warm season grass. Animals will often avoid E+ tall fescue given a choice, so this reduces toxic effects. But this option generally does not eliminate 100% of the problems with the endophyte.

3. Avoid grazing tall fescue during critical periods. Endophyte effects can be reduced by grazing in late fall or early winter when temperatures are mild. Grazing during very cold weather, or when the temperature begins to climb above 80oF in spring and summer, will cause the greatest problems with endophyte toxicity.

4. Plant endophyte free (E-) tall fescue. Endophyte can be eliminated when tall fescue seed is stored in a barn for a year or more, while some of the seed remains viable. Well-managed pastures, containing a very low level of endophyte, have persisted for more than 20 years at the Eastern Research Station at Haskell. But E- tall fescue is less stress tolerant and in most cases will probably not persist as well as E+ tall fescue in eastern Oklahoma.

5. Plant tall fescue containing a novel endophyte. Novel entophytes benefit the plant by increased stress tolerance, but do not result in the animal health and performance problems of wild type endophyte. Seed sold as MaxQ or ArkPlus tall fescue contain novel entophytes.

Endophyte Free Tall Fescue:
Producers wishing to establish endophyte free or novel endophyte tall fescue must first kill any existing tall fescue. Although the endophyte does not pass from plant to plant, the endophyte infection percentage of a pasture can increase in time. This happens when E- plants die, and E+ plants produce seeds and establish new E+ plants. This is why all tall fescue plants must be killed prior to a new seeding. The "Spray, Smother, Spray" strategy is a good approach to renovating a pasture. Glyphosate (Roundup) is sprayed in late winter or early spring. A smother crop of a warm season annual grass (such as pearl millet or sudangrass) is planted in spring and harvested as hay to shade tall fescue escapes and prevent seed production. A second application of glyphosate is made in late summer to kill any remaining tall fescue plants ore seedlings, and the new planting is made in September to October. It is very important not to feed hay containing tall fescue on E- or novel endophyte pastures, as this hay may be a source of seed containing wild type endophyte.