Two horseradish parasites

[Chris Yeates]

Recorded within a week and little more than a kilometre apart, these two fungi are superficially very similar, but as you can see from the micro-shots, quite different.

The fungi are related, both being anamorphic states of ascomycetes in the Mycosphaerellaceae.
One of the key features - the dark bunches of conidiophores of the Cercospora versus the colourless ones of the Ramularia - can just about (with a decent handlens) be made out in the field - though always worth double-checking when starting with these things.

Note how the conidiophores tend to cluster through the stomata on the leaves' under surfaces - the easiest point of exit.

[CJohnsonOHBR]

Thank you Chris for another fascinating presentation.
As soon as it stopsblowing half a gale and raining I'll have a look at our horseradish plants.

Christine