Two horseradish parasites

Plant diseases
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Chris Yeates
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Location: Huddersfield, West Yorkshire

Two horseradish parasites

Post by Chris Yeates » Tue Sep 08, 2020 10:00 pm

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.
Cercospora armoraciae 0a.jpg
Ramularia armoraciae 0a.jpg
"You must know it's right, the spore is on the wind tonight"
Steely Dan - "Rose Darling"

CJohnsonOHBR
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Joined: Mon Jul 27, 2015 10:41 am

Re: Two horseradish parasites

Post by CJohnsonOHBR » Thu Sep 10, 2020 7:56 am

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

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