It says the Plenodomus biglobosus  ‘canadensis’ variant was discovered last spring on wasabi plants, while another variant of the fungus, P. biglobosus  ‘brassicae’, was also discovered infecting wasabi at a third site in England’s West Midlands.

DNA analysis of cultures taken from the infected plants confirmed the identification, plant pathologist Dr Kevin King told the Rothamsted Research website. “Greenhouse testing then showed that both variants could cause disease not just on wasabi, but also oilseed rape, cabbage and pak choi,” he said.

“To date, ‘canadensis’ has been reported from brassica species in Australia, Canada, China, Mexico and the USA. However, the present study extends the known geographic range of it, which now includes Europe, having been found in the UK at two geographically distinct sites.

“Moreover, this study also represents, new discoveries for both ‘brassicae’ and ‘canadensis’ as causal agents of Phoma disease on wasabi plants, which previously was thought to be infected only by other variants in Canada, New Zealand and Taiwan.”

Rothamsted Research says there is evidence that P. biglobosus  has become an increasingly problematic pathogen of UK oilseed rape crops in recent years. It notes that previously, only ‘brassicae’ had been reported in European OSR, leading Dr King to believe that further work is needed to check whether this increase is as a result of the new ‘canadensis’ variant or down to recent varieties being more susceptible generally.

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Read the full story on the Rothamsted Research website