Can you identify this?

[WPG]

I noticed today some brown dots on my overwintered broad beans (aquadulce). The plants are otherwise healthy, sturdy and about 4 inches high

But around the edges of the leaves, on about a quarter of the plants, there's reddish brown or tan coloured marks (no mould that I can see, and the stems don't seem to be affected). Is this the start of chocolate spot? Or maybe rust? Or something else? Is there anything I can do to stop it spreading?

Sorry photo a bit blurry (click pic for larger version)

[Two_Sheds]

Chocolate Spot.


Wow, that's early

"Maximise air flow around the plants by wider spacing and avoid damp, humid sites"

[WPG]

Oh dear. And I'd been congratulating myself on seeing them through the winter, seems pride comes before a fall!
I probably did sow too close together, hadn't expected them all to germinate - will pull up the affected ones and hope the others are OK.

[Jamesy_uk]

I had chocolate spot last year but once they started growing full speed as it warmed up it didn't really seems to affect the plants much.

[WPG]

That's good to hear Jamesy - maybe they'll be OK then.

[mudpies]

Mine looked exactly the same today WPG - gutting when it's one of the few things showing any sign of life at the mo!
Glad I don't have to pull them all up.
I was going to direct sow another batch soon. Should I do this away from the affected lot?

[WendyC]

Never grown broad beans but would picking off the affected leaves help? Might stop the spread. Depends how many leaves or you could end up with a stick!

[Potstubsdustbins]

If it is chocolate spot and it certainly looks like it. You would be better off lifting the plants and destroying them to prevent it spreading. Certainly don't plant further beans near them.

CS is a fungi, botrytis fabae and its main method of transport is airborne spores particulary in wet weather. Wet weather will also cause the spots on the leaf to grow, killing the leaf and then the plant.

You could of course keep your fingers crossed that it is didymella fabae which looks similar but is far less devastating.

Potty

[mudpies]

Urrgh - sounds grim then - can it spread to peas do you know? And is there any clever little remedy that will treat it?

[Potstubsdustbins]

If you google chocolate spot you will find one or two methods of control but they are mainly chemical.

By far better is prevention, good rich soil for strong plants and don't over crowd

Colin