Endophytes are organisms that live in plants. In tall fescue, the most important endophyte is Neotyphodium coenophialum, a fungus that causes fescue toxicosis. The tall fescue endophyte produces toxins that have a devastating impact on grazing livestock, as these toxins cause poor weight gain, low calving rate, and poor milk reproduction. In terms of "straight dollars," the endophyte toxins cost Missouri beef industry $160 million each year.
In the 1980s, plant breeders removed the toxic endophyte and released "endophyte-free" tall fescue. But the endophyte-free varieties did not persist well. Researchers have since learned that the endophyte in tall fescue helps the plant withstand drought, insects, and pathogens.
In recent years, researchers have taken the endophtye-free plants and inserted them with new strains of the endophyte. These new strains produce little or no toxins, but they greatly increase plant persistence compared to the endophyte-free varieties. The new strains are called "beneficial" because they help the plant survive. Occasionally, they are called "novel" because they are different than the common endophyte and offer a unique use for endophytes. If the new strains produce no toxins, they are called "non-toxic endophytes."
Varieties with Beneifical Endophytes
The first beneficial endophyte to hit the market was MaxQ, which was inserted into Jesup tall fescue. Sometimes this variety is called "Jesup MaxQ," but it is usually simply referred to as "MaxQ." The endophyte was collected and tested by AgResearch, New Zealand. It was inserted into Jesup, an endophyte-free tall fescue developed at the University of Georgia. Jesup MaxQ is being marketed by Pennington Seed Company (Madison, GA).
MaxQ has been tested in grazing trials across the US and has proved to be completely nontoxic to all classes of livestock. In fact it is not only nontoxic, it is also highly nutritional. For the past few years, Jesup MaxQ has been the primary recommendation from MU forage specialists to producers wishing to establish a cool-season perennial pasture of good quality.
A follow-up release from Pennington is Texoma MaxQII. This cultivar was developed by the Noble Foundation for the central and south central U.S. It has shown superior growth in states south of Missouri. Tests may prove it can perform well in our state as well.
A new variety, BarOptima PLUS E34, was recently released by Barenbrug USA (Tangent, OR). According to their plant breeders, the "E34" endophyte was discovered internally. Barenbrug screened its germplasm bank for endophytes that produced low levels of ergovaline then inserted these endophytes into high quality tall fescue plants; the high quality refers to high digestibility and soft leaf traits of the grass plant. The plant breeding proceeded after the endophyte was inserted. This means that BarOptima PLUS E34 was developed in association with the endophyte; the plant breeders did not simply inoculate a preexisting variety.
BarOptima PLUS E34 has been tested in university trials since 2002, although not as many trials yet as Jesup MaxQ. The test code for this variety is 'FA BE9301' or 'BAR FA BE9301A'. BarOptima PLUS E34 has shown excellent persistence in grazing trials. It differs from other varieties with beneficial endophytes in that it produces low levels of endophyte toxins. However, data from grazing trials at Hope, Arkansas show these toxins levels were low enough to not hamper animal performance. Animals grazing BarOptima PLUS E34 performed as well as those grazing Jesup MaxQ.
BarOptima PLUS E34 is currently being sold through various dealers and retailers around the country, including Missouri. It is increasingly being planted by the new large grazing dairies in our state. The cost of seed is just under $100 per acre at the company's recommended seed rate of 25 lb/acre.
A variety soon to be in the market is "DuraMax Armor," with Armor being the name of the endophyte. This variety is being sold by DLF International Seed (Halsey, OR). The plant genetic development occurred at Auburn University with the goal of good performance in the transition zone of the US, a region that includes Missouri. The endophyte strain in this variety, Armor, was collected from Northern Africa and is licensed from the University of Arkansas. The Armor endophyte does not produce an ergovaline alkaloid, so there is no risk of fescue toxicosis. Armor does produce compounds known to deter insects while having no harmful animal impact.
DruaMax Armor has been entered in variety trials under the designation IS FTF-31. Two of the variety trials are being conducted at the University of Kentucky and Cornell University. DuraMax Armor is planned for limited market availability in summer or fall of 2011. Pricing has not been determined at this point, however the intention is to price DuraMax Amor at a level that encourages broader acceptance by cow-calf and stocker operators in the transition zone.
In addition to these cultivars, one is being developed by the University of Kentucky and another one to be called ArkShield. Be on the lookout for these two new cultivars as they undergo testing and hit the shelves soon.
Planting the New Varieties
Missouri producers who want to plant the new varieties should remember to plan ahead. The old tall fescue is not killed by simply spraying or even spraying and plowing. In our state, new plantings need to follow a recipe known as "spray-smother-spray" with a fall planting in mind (Roberts and Andrae, 2010). This recipe calls for a spray of glyphosate in May, followed by the planting of a smother crop for the summer months, followed by a second glyphosate spray in late August, followed by a no-till planting of the new variety. The reason for the spray-smother-spray method, is that old tall fescue can come back from volunteer seed in the soil or from tillers that escaped the first spray.
Future research may show that a new establishment procedure will work in Missouri. Researchers in Georgia and South Carolina have tested a "mow-mow-spray-spray" recipe (Roberts and Andrae, 2010). It calls for two mowings in the spring to prevent seed from developing, followed by a spray 6 weeks prior to planting and a second spray immediately prior to planting. This recipe allows the new variety to be drilled directly into the old stubble, and it has proven effective in all cases tested in the southern US.
Producers wanting to try these new varieties should contact their local extension specialist, as well as representatives from the companies listed above.
Roberts, C., and J. Andrae. 2010. Fescue toxicosis and management. ASA and CSSA, Madison, WI.
REVISED: September 26, 2011