I have a brown spot developing on leaves of normally healthy runner beans
By Beanleaf
Hamphire,
United Kingdom 
White Lady runner beans have yielded excellent crops this year but lower leaves now browning as picture. Doesnt look like Halo Blight. Wanted to save seed as such a good cropper
14 Sep, 2009
Answers
It's probably chocolate spot. Unfortunately it transfers to the pods but they are still edible. I would be inclined not to save the seeds, buy some new ones. Don't compost the bean plants as this will spread the disease next year.
14 Sep, 2009
is it just normal age related death as it is starting with the oldest leaves?
if it is you can save the seed no problem.
14 Sep, 2009
Which is why seeing a pix. would be good :-)
14 Sep, 2009
Sorry no pix. just a question mark
14 Sep, 2009