Agar method for the detection of Microdochium nivale and Microdochium majus on Triticum spp.

摘要

A method for Microdochium nivale (Fusarium nivale) was originally published in the ISTA Handbook of Seed Health Testing in November 1964 as S.3. No. 33 (Anon.,1964), and was never revised for inclusion in the second edition of the Handbook. The agar plate test proposed is based on the comparative test organized by the ISTA Seed Health Committee and experience of routine testing in a number of laboratories. Summary of changes to original working sheet: Either potato dextrose agar (PDA) or malt agar (MA) can be used; incubation temperature reduced to 20 °C; incubation in dark followed by 3-4 h in daylight or under near ultraviolet (NUV); changes to format and layout. Within Microdochium nivale, two varieties were recognized: M. nivale var. nivale andM. nivale var. majus. In 2005, Glynn et al. provided molecular-based phylogenetic evidence of two species when taken together with biological differences already reported, thus elevating the two varieties to species status, M. nivale and M. majus. Bothspecies are detected on PDA and Malt Agar; however, visually it is not possible to distinguish between the two, and there is an overlap in spore morphology, making it difficult to separate the two species on agar. Both species cause seedling blight in wheat, although symptoms may be more severe with M. majus.