Broad bean plants gone black

[Bikerbob]

Hi, Has anyone else had problems with their broad bean plants going black and dying this year?
Each year I grow B.B. Sutton’s in pots and plant them out in the greenhouse for an early crop. Never had any problems before. Fresh seed, plants about 50mm tall and lush green. Very healthy plants watered in and spaced well apart. A few started to droop and go black and died within about a week. Now after 3 weeks virtually 40 plants now dead or dying.

I am sure it isn’t frost that is killing them. Fungus perhaps? Anyone know please? I am pulling the last few out and burning them, then a good dose of ***** fluid.

I would be interested if anyone else has the same problem though. Also what the cause is. ‘ have attached some photos in case it helps

[veggiechicken]

Hi Bob and welcome.
I don't know whereabouts you live but here, in sunshiny South Wales my plants were flattened by snow twice and looked a write off. Against expectations, they've bounced back and sent up new shoots.
Have you had any extreme weather - wind, hail, heavy rain?

EDIT - Ignore all that ^^^ just noticed that you're growing in a greenhouse.

[nickdub]

top looks to have died back a bit in both photos - most likely either frost damage or slugs - as long as the roots were OK they would have regrown I think - I don't think its a disease problem.

[Snoop Puss]

That looks just like frost damage to me. But if they're in a greenhouse, could it be quite the opposite: they've got too hot?

[nickdub]

Should be possible to tell about frost from the date of the damage - I had water containers frozen solid in my poly-tunnel in that last cold snap we had a few weeks ago.

[Penellype]

I'm no expert on broad beans, but could this be some sort of botrytis? Broad beans get a variety of this called chocolate spot, which doesn't look quite right, but the fact that the plants have suddenly wilted and that it appears to be spreading appears to point to something fungal. The weather has been cool and damp, and fungal diseases love those conditions in greenhouses - I have lost lettuces to botrytis this spring in my friend's greenhouse.

I think you are right to get rid of them and disinfect the greenhouse. Better safe than sorry, and from the photos they don't look likely to survive.

[Bikerbob]

Broad bean and fungus

Hi Penellype, Thanks for your comments and suggestions. Yes that would fit the issue. I know it cannot be frost or too much heat. I live in Leigh-on-Sea in Essex. Yes we get frosts but in the past I have had BBs growing vigorously in the greenhouse when it has been snowing.
The greenhouse has automatic vents so there is no chance of over heating.
However the water table is very high at present even though I live on the top of a hill. Since posting my cry for help I now have black leaves on the borlotti beans on the other side of the greenhouse. The parsley is still lush green so hope I can retrieve it.
I have looked up info’ on botrytis and it appears to fit the symptoms. I just hope J..... fluid can kill it.
Thanks once again - regards - bikerbob

[TheCyclingProgrammer]

Also in Essex. All of my broad beans got hit by frost resulting in blackened leaf tips. I removed some of the really badly hit foliage. I also removed a couple of badly damaged stems a few months ago which caused them to branch and recover.

Mine also have chocolate spot. I sowed mine in October (Aquadulce Claudia) and they are about a foot tall now. I expected them to be taller but I guess that might just be due to the bad weather in March. Flower buds are just coming through.

[nickdub]

Also in Essex. All of my broad beans got hit by frost resulting in blackened leaf tips. I removed some of the really badly hit foliage. I also removed a couple of badly damaged stems a few months ago which caused them to branch and recover.

Mine also have chocolate spot. I sowed mine in October (Aquadulce Claudia) and they are about a foot tall now. I expected them to be taller but I guess that might just be due to the bad weather in March. Flower buds are just coming through.

My experiences with fungus diseases on plants, particularly strong growing things like beans, is that when plants are stressed by the weather they can be affected badly by the disease, but when the weather improves the new growth will often get the better of the problem and grow on to crop OK. A bit like a young person with a cold their natural good health once they fight through the beginning will usually allow them to recover quickly.

[Bikerbob]

Frost damage or slugs

top looks to have died back a bit in both photos - most likely either frost damage or slugs - as long as the roots were OK they would have regrown I think - I don't think its a disease problem.

Hi,
Thanks for your suggestions / comments.

Slugs can be ruled out I think as the ground around the plants was the only part that had been watered. No evidence of their slime.

When I dug what was left of the plants up the original bean in most cases was either covered in white mycelium and very soft, or there was nothing under the ground. Black stem continued a few mm into the ground.

Yes agreed the blackened tops does look like frost damage but I cannot understand how it can occur inside a greenhouse. The plants that went black were not all in one area. Some suffered that were next to the concrete foundation strip, whilst others were next to the path 700mm away. Plants have been turning black since writing my plea and there hasn’t been any frost. Or even that cold.

The local farmer lost his field of BBs the year before last. All the plants were tall and podded. Not much leaf and then looked like they were covered in soot. That was about a mile away. I suppose I should find out which farmer owns that field and ask him what happened.

Thanks also to others that responded to my post - much appreciated.

[nickdub]

no problem - as you say it certainly seems impossible it could be frost and as you can also rule out slug damage, disease is all that's left. Wishing you better success with your next crop.

[Bikerbob]

Fungus?

Hi,
I looked in “The Vegetable Expert” by Dr D.G.Hessayon and on page 21 he shows virtually the issue with BBs black and wilted.

Although the book is somewhat old and states Chestnut Compound as a remedy (banned by the EU as it contained Copper Sulphate (now sulfate). Further reading found the RHS have produced a pdf on alternatives to use.

I have attached a photo from the book if it can help anyone else with a similar problem.

[nickdub]

I used to make my own mixture of Copper Sulphate and lime as a fungicide to spray on my fruit trees (in my case to save some money, not because it was banned then) - haven't bothered with it for ages though, as its quite a bit of work.