Consolidated summary of key points from the Ryegrass Endophyte Symposium: a farm consultant's perspective

Abstract

Background on endophytes Endophyte is a fungus, which exists inside individual ryegrass plants, and reproduces through infecting ryegrass seed. Endophytes are very widespread in New Zealand pastures, being present in 70% of ryegrass tillers in Southland, and 99% in the upper North Island. The presence of endophyte confers benefits to the host ryegrass plant, inhibiting its susceptibility to grazing by: • domestic animals. • above ground insects, particularly. (a) Argentine stem weevil (b) Black beetles (c) Mealy bug. General awareness of its existence, and understanding of its role, began in the 1980s, and is still expanding. Knowledge of its existence and impacts now allow us to better explain the reasons for "inexplicable" results from scientific trials before 1980. It may also be a prime cause of summer "ill thrift". The endophyte responsible for ryegrass staggers in cattle, sheep, deer and horses occurs in perennial ryegrass and some hybrid ryegrass plants. Endophytes that have toxic effects on grazing animals also occur in other grass species, for example, the endophyte in roadside tall fescue that causes "fescue foot". However, commercial cultivars of tall fescue sold in New Zealand do not contain toxic endophyte.