Effects of different fungicides on the severity of phoma stem canker

Thomas Sewell, Yongju Huang, Henrik Stotz, Mike Ashworth, Philip Walker, Faye Ritchie, Bruce D.L. Fitt

Research output: Contribution to conferencePoster


Phoma stem canker, a disease of oilseed rape (Brassica napus) caused by
sibling pathogens Leptosphaeria maculans and L. biglobosa. Both pathogens
follow a monocylic disease cycle that causes leaf spotting in autumn/winter
and stem cankers in spring/summer. Most severe cankers decrease
transportation of water and nutrients. Fungicides are important for phoma
stem canker control. Triazole fungicides currently dominate the market,
although reduced sensitivity in some plant pathogen species is a concern.
Moreover, L. maculans and L. biglobosa have shown differing level of
sensitivity to triazole fungicides. Therefore, increased knowledge on
controlling phoma stem canker using non-triazole based fungicides is
essential. Field trials were established for 2013/2014 cropping season. Four
fungicides were applied: penthiopyrad, picoxystrobin, prothioconazole and
a novel fungicide. Spray timings were divided into three sprays T1 (phoma
leaf spotting incidence ≥10%), T2 (3/4 weeks post T1) and T3 (Sclerotinia).
Phoma leaf spotting incidence and stem canker severity were recorded. In
vitro sensitivity testing was done on one L. maculans (ME24) and one L.
biglobosa (68) isolate. Prothioconazole showed no noteworthy advantage
over the novel fungicide in canker severity scoring. No significant difference
in growth inhibition was observed between L. biglobosa and L. maculans (P
≤ 0.05) when treated with novel fungicide. Canker severity indicates that
the novel fungicide has a similar efficacy to triazole fungicides. Fungicide
sensitivity testing shows that L. biglobosa does not have an increased
sensitivity to non-triazole fungicides. This interaction suggests that the
novel fungicide could be used to control both L. maculans and L. biglobosa
Original languageEnglish
Number of pages1
Publication statusPublished - 2014
EventBSPP Presidential Meeting 2014 - St Andrews, United Kingdom
Duration: 1 Sept 20142 Sept 2014


ConferenceBSPP Presidential Meeting 2014
Country/TerritoryUnited Kingdom
CitySt Andrews


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