Tall Fescue

Tall fescue seed carries Epichloë coenophiala, a fungus transmitted in the seed rather than between plants. It confers the drought tolerance, insect resistance and persistence that made the grass ubiquitous, and it produces ergot alkaloids, chiefly ergovaline, in the plant tissue the animal eats.

Management combines resistant varieties, rotation, monitoring, and — where justified — locally authorized control products applied according to their labels.

Cattle grazing wild-type endophyte-infected fescue show reduced weight gain, impaired reproductive performance and elevated body temperature — a syndrome collectively called fescue toxicosis. The alkaloids are vasoconstrictive, so the effects are worst in summer heat, when the animal cannot shed heat properly, and appear again as cold-weather extremity damage.

Soil suitability should be assessed with local soil survey information and, where available, field testing.

The commercial answer is a selected endophyte strain that keeps insect deterrence and persistence while producing little or no ergovaline. AR542, inserted into the cultivar Jesup and sold as MaxQ, was the first widely released example. Grazing trials on novel-endophyte fescue show good animal performance without toxicosis symptoms.

Fertilizer rates, timing, and forms should follow local soil tests and regional guidance. AgricultureID does not publish universal fertilizer recommendations.

Removing the endophyte altogether solves the animal problem and creates an agronomic one: endophyte-free stands lack the insect resistance and stress tolerance the fungus supplied and thin out under the conditions tall fescue was chosen for. That failure is why the novel-endophyte route exists.

Because the fungus is seed-transmitted and is a living organism, its viability declines in warm storage while the seed itself stays viable. Seed sown from a poorly stored lot can therefore establish a stand with far less endophyte than the label implies, which matters in both directions — for persistence and for toxicity.

Tall fescue roots deeper than the other sown cool-season grasses and holds green leaf through dry spells that check ryegrass. That is what makes it a transition-zone grass rather than a cool-temperate one, and it is also why it is used for conservation seedings and erosion control well outside grazing systems.

The grass tolerates hard grazing and accumulates autumn growth that stands through frost with little quality loss — the basis of stockpiling for winter grazing. Stockpiled fescue is also the highest-alkaloid material of the year on a wild-type stand, so the practice and the hazard arrive together.

Converting a wild-type stand to novel endophyte is a two-season operation: the existing sward must be killed and its seedbank exhausted before reseeding, because volunteer wild-type seedlings will reinfect the new stand and undo the change. Partial renovation reliably fails for that reason.

Both authorities now accept Lolium arundinaceum, transferring the species out of Festuca. Older literature, seed labels and recommended lists use Festuca arundinacea, and Schedonorus arundinaceus appears as a third treatment, so a reader matching names across sources will meet all three for one grass.