Mildew on Foxglove Leaf

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Lancashire Lad
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Mildew on Foxglove Leaf

Post by Lancashire Lad » Tue Jun 30, 2015 9:03 pm

Found on Saturday 27th June, on the underside of a live but sickly looking Foxglove leaf.

I'm assuming it must be a Mildew of some sort, but I'm getting nowhere fast in trying to identify it, (along with a few others too :oops: :roll: ).

I'd be very grateful if anyone could put me onto the right track.

Click on images to view at full size.
Foxglove.jpg
Macro shot of the infected Foxglove leaf
Foxglove 01 x100 with Scale 270615.jpg
Above image is x100
Foxglove 02 x200 with Scale 270615.jpg
Above image is x200
Foxglove 03 x100 with Scale 270615.jpg
Above image is x100
Foxglove 04 x200 with Scale 270615.jpg
Above image is x200

Regards,
Mike.
Common sense is not so common.

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Chris Yeates
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Re: Mildew on Foxglove Leaf

Post by Chris Yeates » Tue Jul 07, 2015 5:31 pm

Sorry - missed this one
another case of domination of the image by hairs, like viewtopic.php?f=9&t=224&p=1101&hilit=hairs#p1100 - difficult to avoid with plants like Digitalis. The last image seems to show aseptate conidia (a higher mag. would have been useful); that and macro morphology points to a Ramularia or one of its allied genera; unlike downy mildews these fungi actually cause brown necrotic areas, often delimited by leaf veins. There are other groups which parasitise living leaves other than rusts, smuts and mildews.
The Capnodiales used to be a relatively small order but recent molecular work now includes the Mycosphaerellaceae in it. That family has anamorphs in Ramularia (a 'hyphomycete') and Septoria (a 'coelomycete' - thus underlining the artificial nature of those groupings).
This is probably Ramularia variabilis. Note here how the fungus emerges in fascicles through the stomata on the underside of the leaf, hence that 'tufted' appearance:
best wishes
Chris
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Ramularia variabilis.jpg
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Lancashire Lad
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Re: Mildew on Foxglove Leaf

Post by Lancashire Lad » Tue Jul 07, 2015 6:40 pm

Thanks Chris.

Unfortunately I'd given up on this and have binned the sample leaf, so I can't provide any more shots.

Armed with your above info though, one to look out for again!

PS: In the Meadowsweet mildew thread of mine that you linked to, I had made a final post with further images etc.
: - viewtopic.php?f=9&t=224&p=1101&hilit=hairs#p1109

Is there anything that can be added to your first reply there - in light of the additional photos/info?


Best regards,
Mike.
Common sense is not so common.

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