You have read in popular articles and trade magazines about endophyte enhanced grasses. What is an endophyte? In this case, an endophyte is actually a fungus that lives inside (internally) a plant. For turfgrasses, the Acremonium spp. of fungus has received the most attention in the last 10 - 12 years, after it was discovered that the presence of the fungus was associated with long term survival of turfgrass plants.

The presence of the endophyte causes the production of loline alkaloid chemicals. These chemicals have demonstrated natural resistance/avoidance to grasses which contain the endophyte fungus. These chemicals allow turfgrass plants to either ward off or tolerate debilitating infestations of aboveground feeding insects. These include chinch bugs, stem weevils, sod webworms, armyworms and aphids. They do not have this effect on underground feeding insects, such as whitegrubs. The fungal endophyte is found in the leaf sheath, where many insects feed and seek protection. The loline chemicals are not transmitted to the roots. Studies involving animal performance demonstrate clearly that the endophyte is not desirable, if the grass is to be used as a forage. Presence of the endophyte causes hoof swelling, poor animal coats, elevated temperatures, unthrifty production and low weight gains. The grass species which have been shown to be naturally infected with the endophyte include tall fescue (festuca aurundinacea), perennial ryegrass (Lolium perenne), chewings and hard fescue (fine fescues). There is significant acreage of these grasses for both forage and turf uses. When buying seed for animal consumption, make sure if possible, that the seed is endophyte free. The tag should state the percentage of seed which has the endophyte. For feed sources, 10% or less is desirable. The endophyte is passed maternally only, and is not transmitted through pollen. Instead, the fungus invades the seed and is stored inside the seed directly. It does not become part of plants DNA directly.

For turf purposes, endophyte enhanced seed is commercially available in most states. One of the first turf-type perennial ryegrasses released including the endophyte was called "Repell". Many more varieties now are endophyte enhanced. Check the label and look for the percentage of seed which is endophyte enhanced. If it's not on the tag, ask the dealer to confirm the percentage. Breeders have tried to make forage types endophyte free and turf types endophyte enhanced. Mowing does not remove the endophyte. So if you plan to use a grass for either purpose, make sure that it contains no endophyte. For turf purposes, endophyte enhancement offers natural biological control of some of the above ground feeding insects in lawns.