Ryegrass endophyte: a New Zealand Grassland success story

The discovery in 1981 that ryegrass endophyte is responsible for ryegrass staggers has required a total revision of our understanding of ryegrassbased pastures. The effects on grazing livestock range from obvious clinical disorders to chronic impairment of productivity. On the other hand, endophyte infection is essential to ryegrass persistence in most of New Zealand, protecting the plant from some invertebrate pests and from over-grazing, and perhaps promoting its tolerance of moisture stress. Vigorous, endophyte-infected pastures sometimes include less clover than pastures relatively free of endophyte. Active compounds produced by the endophyte have been identified, and conditions causing high levels of them have been documented in part. Endophyte strains which do not produce the compounds responsible for livestock toxicoses offer exciting new possibilities in grassland agriculture. Keywords: invertebrate pests, mycotoxicoses, Neotyphodium lolii, perennial ryegrass, ryegrass staggers