Endophyte infection of tall fescue and the impact of climatic factors on ergovaline concentrations in field crops cultivated in southern France.

Tall fescue (Lolium arundinaceum) infected by Epichloe coenophiala contains ergot alkaloids responsible for fescue toxicosis in Australia, New Zealand, and the United States, with only a few cases occurring in Europe. The detection of Epichloe in 166 L. arundinaceum collected in southern France revealed that 60% were infected, 51% being high ergovaline producers. The ergovaline level in endophyte-infected tall fescue Kentucky 31 was monitored during 3 years in various parts of the plant. Maturation of plants, recorded according to the BBCH scale, appeared to be the main factor for estimating the risk of toxicity. Ergovaline levels of ≥300 μg/kg dry matter were obtained at the end of spring, the beginning of autumn, and mid-winter. Positive correlation between ergovaline level and cumulative degree-d was observed, whereas rainfall had no effect. These results suggest that the lack of fescue toxicosis observed in France cannot be explained by the lack of ergovaline in tall fescue.