Occurrence of the fungal endophyte Neotyphodium coenophialum in leaf blades of tall fescue and implications for stock health

摘要

Abstract Leaf blades of tall fescue (Festuca arundinaced) plants infected with the endophytic fungus Neotyphodium coenophialum (= Acre‐monium coenophialum) have often been assumed to be endophyte‐free. However, fungal colonies identified as N. coenophialum developed following incubation of surface‐sterilised leaf blades from endophyte‐infected tall fescues on antibiotic potato dextrose agar. A standardised fungal isolation technique was developed to assess the distribution of hyphae within tall fescue leaf blades in three USA‐bred cultivars ('Georgia 5’, ‘Kentucky 31’, ‘Jesup') and a roadside population (MRSP) from the Manawatu region, New Zealand. Leaf blades of the three USA‐bred cultivars were typically sparsely colonised. In contrast, extensively colonised leaf blades were present in many MRSP plants, particularly in autumn. Ergovaline concentrations of up to 3.9 ppm (mean 2.5) were present in leaf blades of the MRSP grown in a glasshouse. Ergovaline at lower concentrations (mean 0.4 ppm) was also det...