1.0 POPULAR SUMMARY Most ryegrass based pastures grazed by Merinos will contain endophyte. Endophytes are fungi that exist inside plants and are transferred via seed. Endophyte exists in a normal symbiotic relationship with ryegrass protecting it from Insect attack and offering other advantages. Endophytes produce a wide range of compounds including peramine,lolitrem B and ergovaline. Peramine offers some protection to the plant from insect attack,especially argentine stem weevil. Lolitrem B is a neurotoxin causing ryegrass staggers in animals. Ergovaline lowers blood prolactin levels and causes heat stress. Some of the above compounds,in combination with other unidentified compounds. depress intake,liveweight gain and cause scouring and dags in sheep. Non-toxic strains of endophyte have been selected. 。 The mo eiecsomgan9anenasrsvanoBcece。 is AR1 which produ Is aval eoneaantian .a number of prevention and control measures against the toxins have been tried but the only one offering complete protection is to replace the resident ryegrass pastures with AR1 ryegrass. Establishment of AR1 requires a spray/crop or double spray treatment to reduce toxic of wild occur after three or four years and precautions PAGE3 1.0 POPULAR SUMMARY • Most ryegrass based pastures grazed by Merinos will contain endophyte. • Endophytes are fungi that exist inside plants and are transferred via seed. • Endophyte exists in a normal symbiotic relationship with ryegrass protecting it from insect attack and offering other advantages. • Endophytes produce a wide range of compounds including peramine, lolitrem B and ergovaline. • Peramine offers some protection to the plant from insect attack, especially argentine stem weevil. • Lolitrem B is a neurotoxin causing ryegrass staggers in animals. • Ergovaline lowers blood prolactin levels and causes heat stress. • Some of the above compounds, in combination with other unidentified compounds, depress intake, liveweight gain and cause scouring and dags in sheep. • Non-toxic strains of endophyte have been selected. • The most promising is AR1 which produces peramine and protects the plant from insect attack with no ill effects on grazing animals. It is available commercially. • A number of prevention and control measures against the toxins have been tried, but the only one offering complete protection is to replace the resident ryegrass pastures with AR1 ryegrass. • Establishment of AR1 requires a spray/crop or double spray treatment to reduce toxic seed. • Ingress of wild type ryegrass can occur after three or four years and precautions should be taken to prevent seed entry. PAGE 3