Black spot on yucca

Does anyone else have this problem on yuccas.
I also find it on agave plants.
It starts as a small black spot that increases in size until the whole leaf is black and rotting.
I've seen it a number of years but this year seems worse than most.
I've tried all sorts of fungicides, but nothing seems to work.
Any ideas.

 

Yes Pete I have had the same problem on my favourite Yucca I chopped it down and the new shoots came up the same.I still have the plant or now plants but am at a loss what to do!!!!!HELP. :confused: :confused:

 

It seems common, even seen it on plant for sale at garden centres, was kinda hoping strongy might come up with some trade secret. :D

 

Uugghh!!! That looks awful, and haven't noticed it on my Yucca or Agarves. If it survives a chop-down it sounds like a virus, so fungicides wouldn't help. Or it could be something that lives in the soil? I'm off to Spain a fortnight yesterday and will show your picture round some garden centers, they might recognise it.
Nik

 

Hi, Pete - I've looked it up in the RHS pests and disease book, and there's a perfect decription of your prob - and a pic where several circles have fused together. It's called Yucca Leaf Spot!! Does what it says on the label?? Cause - fugus - either cercospora concentrica, or coniothyrium concentricum. Treatment, they say - pick off severely affected leaves!!

 

Thanks Nik,
Dendy, if I do that I wont have much left on some. :( :D

 

You definitely need a trade secret from Strongy - PM him!!

 

In the 18th century, when the UK government started to collate "cause of death of its citizenry" statistics, one of the column headings was "Dead in the street". When I saw dendrobium's "Yucca Leaf Spot" diagnosis I thought "Gosh, we haven't progressed much in 300 years have we". :D Sincere apologies to dendrobium, its just that I am a very cynical old piece of turf. :D :D

 

Come on Nik, grovel!! "It does what it says on the tin!" What else are you going to call it!! Just look it up in the books - just like black spot, coral spot - it describes it exactly. And what about potato blight?

 

dendrobium, I'm grovelling. :D :D :D and Petes Agarve is "dead in the pot". :D :D :D