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Seimatosporium cf. lichenicola on Rosa canina ?
Thorben Hülsewig,
04-05-2018 22:52
today i found this black spots on Rosa canina and i think it may be the genus Seimatosporium. The conidia are only 3-septate and appendages are up to 10 Micrometer long.
Could this be Seimatosporium lichenicola ?
best regards,
Thorben
Joey JTan,
05-05-2018 04:56
Re : Seimatosporium cf. lichenicola on Rosa canina ?
I think of S. lichenicola as having more pigmented, thicker-walled, clavate conidia with wider and darker septa, but your conidia might be young. Seimatosporium lichenicola also often lacks appendages, but your dimensions are similar to those reported by others for this species. I looked at Shoemaker (1964) and didn't find a satisfactory match, e.g. similar to Seimatosporium discosioides except for the appendage length and possibly habit (I'm not sure if S. discosioides is reported from stems). Doesn't match S. rosae either.
Shoemaker, R.A., 1964. Seimatosporium (= Cryptostictis) parasites of Rosa, Vitis, and Cornus. Canadian Journal of Botany, 42(4), pp.411-421.
Chris Yeates,
05-05-2018 17:11
Re : Seimatosporium cf. lichenicola on Rosa canina ?
I too cannot make a satisfactory match; though it surely isn't S. lichenicola, which in my experience usually has collapsed walls.