Evaluation of pathogenicity and aggressiveness of F. langsethiae on oat and wheat seedlings relative to known seedling blight pathogens

Fusarium and Microdochium species are causal agents of seedling blight of small-grain cereal crops where they may contribute to a significant reduction in crop establishment and final yield. Two experiments were carried out to investigate the potential pathogenicity and aggressiveness of F. langsethiae, a recently identified fungus linked with the contamination of cereals with high levels of the trichothecene mycotoxins, HT-2 and T-2. An artificial seed inoculation method involving conidial suspensions was used and the experiments conducted in a growth cabinet set at either 5 or 15°C with a 12 h photoperiod. Known seedling blight pathogens of the genus Fusarium and Microdochium were used for comparison. At 15oC, F. culmorum, M. nivale and M. majus caused seedling blight of oats and wheat with F. culmorum, on average being the most aggressive than the latter two. At 5oC, only F. culmorum and M. nivale caused seedling blight of oats and wheat. Under the experimental conditions employed, F. langsethiae and F. poae failed to produce seedling blight disease indicating that these two species are not pathogenic to oat and wheat cultivars, Gerald and Claire respectively, at the seedling stage of development. They are therefore unlikely to affect crop establishment and other yield components such as tiller number, grain yield per head as well as grain weight if there is no subsequent foot-rot and/or head blight where infected seeds are sown.