Epichloë fungal endophytes – a vital component for perennial ryegrass survival in New Zealand

Pastoral agriculture underpins the New Zealand economy. Its success in generating export income is due to a mild and moist temperate climate, productive soils, innovative farmers supported by an effective research and development system, and an energy efficient production system based on year-round grazing. However, pastoral agriculture is entirely reliant on introduced pasture and forage species and their ability to withstand both endemic and introduced pasture pests. Critical to this is the mutualistic relationship between ryegrass and Epichloë fungal endophytes which provide a range of secondary metabolites that deter herbivory by both ruminants and insect pests. The challenge has been to identify and commercialise Epichloë strains which while providing protection against insect pests, ensuring ryegrass persistence, do not cause animal health and welfare issues. The critical role that Epichloë fungal endophytes play in maintaining pasture persistence and as a result the pastoral economy of New Zealand will be reviewed.