Use of endophytic fungi in turfgrasses: Difficulties in delivery to the market

The agronomic benefits of endophytic Epichloë fungi for the performance of ryegrass (Lolium spp.) and fescue (Festuca spp.) species were first reported in the 1980s. Various Epichloë endophyte species and strains have been shown to produce a series of different alkaloids with considerable impact on insect pests and grazing animals, some effects on nematodes and diseases, and improvements in plant stress tolerance. However, the impact of these alkaloids on plant performance and turf resilience varies across environments, and often relates to specific insect pressures and stressful summer conditions. Over 40 insect pests and diseases have been documented as responding to endophyte infection.

As many Epichloë fungi are seed transmitted, endophyte transmission to the seed is controlled by the levels found in the parent plants and how well the endophyte is maintained during seed production. Endophyte viability in seed lots can drop during storage and transport, especially when stored under high temperatures and humidity. Endophyte growth into seed during seed production can be influenced by the weather, use of fungicides and growth regulators, and the timing of combining after swathing. In the United States, the endophyte infection levels in breeders’ seed of the cultivars used in the National Turfgrass Evaluation Program trials have been reported but currently, no standards exist for labeling cultivars delivered with high endophyte levels. Without suitable protocols and standards, challenges exist in delivering high endophyte infection levels to tall fescue (Festuca arundinacea Schreb.), ryegrass, and fine fescues.