[osg]

Hi all, I have an allotment space in Cork. I am growing some braod beans but in the last 2 weeks I have noticed some choclate or rust like spots on the leaves of the plants also the tip of the flowers and pods are going black and look like they are dying.

The plants in general are continuing to grow and are not dying off on mase. When I peel the black off the pods they are still ok underneath.

Can you advise what this problem is and is there a cure etc?

I don't have a photo but if it helps I can get one tonight.

[sunnymount farm]

Hi osg, I have the exact same problem with my broad beans. The leaves are turning yellow and the bean pods have stopped growing. I've been using a diluted farm yard manure for feed so I thought I poisoned them, but recently with the endless rain and cooler winds I've been thinking that the season for growing beans is nearly over and the stalks are naturally on their way out.
Not sure if this is the case but hopefully someone with more experience will have more info.

[michael brenock]

this is chocolate spot fungus disease of broad beans. There is no 100% cure but you can prevent a lot of infection by pinching out the top 2-3 cms of the tip as soon as you notice the first discoloration. This also prevents bean aphids from spreading. Chocolate spot is encouraged by damp wet weather of which we have had plenty and will affect yields but not the eating quality if you harvest them on time. A second or third sowing in the season would lessen the impact of this disaese, which occurs every year but earlier some years. Adding in diluted farmyard manure would have very little beneficial effect unless the soil was very low in humus or organic matter.
michael brenock horticultural advisor (retired)

[Blowin]

Hi, OSG! In my very limited experience in the UK and over here, broad beans are very disease prone and the only real cure I've ever heard of is to take rhubarb leaves, boil them up, strain off the liquid, put it in a spare trigger spray and spray them. The strong acid is supposed to kill most pests.

However, if you plant your seed in November and let it overwinter, it grows hardier and more disease resistant. Since I've been in Ireland I haven't had any problems and have had good crops.

No good for this year but may help you for next.

[Garlicbreath]

I'll second Blown's suggestion above. I grow broad beans over the winter and all they ever suffer from is some blackfly from about April or May (although none at all this year). They're usually ready to harvest in June freeing up the ground for summer crops.

[michael brenock]

Not all varieties are suitable for overwintering and casualties can be high from rabbits and storm damage as well as late autumn slug onslaught. These early sown beans are not resistant to Chocolate spot but they usually have their growth made and are swelling pods by the time the spot makes it's appearance.
michael brenock horticultural advisor (retired)

[Blowin]

Thanks, Michael. Clearly you have a wider experience than me.

The variety I grew this year to good effect (if any of the others are listening) was 'The Sutton' which bore so many beans we - just the two of us - couldn't use them all in spite of giving some away.

I've got a load on string in the shed, drying out for this year's November sowing I hope.

[sunnymount farm]

I would like to pick up on a point made by Michael.
I've read loads about 'pinching out the top' but I'm not exactly sure what that means. When my stalks started to show the white flower I pinched off about 2 inches from the very top of the plant. Since then the plant hasn't growen any bigger and the white flower turned black and rotted away. Am I using the wrong technique?

[James Kilkelly]

[osg]

Thanks for all your suggestions and helpfull tips. Hopefully I will have a hardier winter crop later on this year.

Being a novice I'm not sure about resetting in November, can I use the harvested pods or do I need to purchase a new bag of seed?
Also do I need to pull the existing plants out of the ground roots and all?
An adjoining plot just cut his about 1" over the ground, will these grow again?

[michael brenock]

you will have to buy fresh seed probably another variety. by cutting back the plants they will not grow again as they are annuals. The person who cut back the plants to within an inch of soil level is attempting to retain the benefit of the nitrogen in the roots, though broad beans are not as good as Runner beans for providing this nitrogen.no need to pull up roots.
As regards pinching back the plants, I think you did it far too early in the development of the plant. better to let 3-4 clusters of pods develop before pinching out takes place otherwise you are frustrating the efforts of the plant tp produce further blossom.
michael brenock horticultural advisor (retired)

[sunnymount farm]

Thanks for the utube video James - very practical
Maybe i'll not pinch so early next year - cheers Michael