French bean problem

[xspye]

I planted my french beans (maxi and blue lake) out in my polytunnel a week ago and they have got new leaves but i have noticed that the old leaves are turning brown. Small light brown patches appear in the center of the leaves and spread outwards. It looks a bit like tomato plants do when they are magnesium deficient only the patches are a darker colour. the plants are continuing to grow and the new leaves look healthy.

Does anyone have any idea what this is or how i can stop it/cure it

I will do my best to get a photo up loaded

[andrewo]

They could be the seed leaves dying or they need a feed, I use a tomato or comfrey feed. It could also be a change in temperature for them, take the leaves off in case it is bacteria and burn them, throw them away. I think more likely it's just needs a feed.