ABSTRACT
Endophyte-induced resistance of grasses to insect pests has been most intensively studied for the interaction of perennial ryegrass with the Argentine stem weevil. Indole diterpenes identified in endophyte-infected perennial ryegrass are lolitrems A to E, lolitriol, and paxilline. Ergopeptine alkaloids occur widely in endophyte-infected grasses, with some six ergopeptine alkaloids having been identified in perennial ryegrass by tandem mass spectroscopy. Peramine may be considered as a cyclic dipeptide formally derived from proline and arginine and is the only example of this structural type identified in endophyte-infected grasses. Endophyte-infected ryegrasses have been shown to suffer less adult feeding and larval damage and to have fewer eggs laid on them than do endophyte-free ryegrasses. Endophyte infection of seeds also protects seedlings from predation by Argentine stem weevils, and transient protection occurs even if the endophyte in the seeds is not viable. The use of endophytes has opened up a new, environmentally friendly means of controlling insect pests of grasses.
