Diversity and prevalence of Fusarium species from Quebec barley fields

Fusarium head blight (FHB), a fungal disease Caused by several species Of Fusarium, results in reduced yields and grain quality in barley (Hordeum vulgare). Various mycotoxins are produced by the Fusarium spp., and these call be very harmful to animals and humans. As a basis for pro,progress in devising future management strategies for FHB in barley, it is necessary to identify the most common Causal Fusarium Spp. in Quebec and to determine whether their prevalence varies over space and time. In this study. we identified the Fusarium spp. present in 144 samples of barley seed harvested in 12 administrative regions Of Quebec in 2000 2001, and 2002. In total, 20 species of Fusarium were identified oil the basis of the morphological characteristics of the fungal isolates. Overall, infection levels (expressed as percentages of infected kernels) were 8.3%. 8.2%, and 36.3%, respectively, for 2000, 201)], and 2002. Three species were responsible for most of these infections: F. graminearum (41.0% of infected seed), F. poae (23.2%), and E avenaceum (15.8%). A fourth species, F. sporotrichioides, although, less prevalent (5.6%), was found in each of the three years. Oil the basis of the broader sampling done in 2001 it appears that geography influenced the species of Fusarium that predominated. Fasarium graminearum was more prevalent in the southernmost regions, F. avenaceum in the easternmost re,,ions, and F poae in the Legions located oil the north shore of the St. Lawrence River. This information should prove helpful in devising the best strategies for effective management of FHB ill Quebec.