Abstract: An endophyte or endophyte culture of N. lolii species is described that, in combination with a host grass does not cause typical symptoms of ryegrass toxicosis in grazing animals and also contains levels of compounds from the class of janthitrems epoxides to individually or in combination protect the host grass from pests or abiotic stresses or both. Uses and methods are also described to produce and characterise the combination as well as alternative uses for compounds from the class of janthitrem epoxide compounds.