I don't really know much but here is a link to some bean diseases. Some of mine have been sick to this year and I think mine is the mosaic virus.

http://vegetablemdonline.ppath.cornell.edu/factsheets/Virus_Beans.htm

Here is a link that might be useful: Bean diseases

This is the one I meant to post. Sorry.

Here is a link that might be useful: Bean diseases2

Thank you, meatysauce, for the link. I wish there were pictures as that would be helpful with identification. I am perplexed! I see you have some problems of your own! Good luck!

Cheryle

The way the leaves look thin and white reminds me of how Leafhopper damage can look on my rose leaves. Leafhoppers are green and very difficult to notice. Leafhoppers suck all the juice out of the leaves. I tried a quick search (I didn't do a real thorough search)for Leafhopper damage on beans and the pics show extensive yellowing, but I think that is later stage damage after the initial white caused by the leaf juice removal. I this might explain your not finding anything to match you pics in bean diseases.
Remy

I always thought that 'fading' was a sign of spider mites. Did you check for spider mites?

It looks like powdery mildew which can also infect the other plants you mentioned.

There are commercial products available to treat the disease but many people spray the leaves with milk. Successful control has been reported using anywhere from 10% to 100% milk. Skim milk or non fat dry milk is probably the best.

Google using milk for powdery mildew. These is a lot of information available.

Greenie,
You could be right. They also suck the leaves dry. If it isn't leafhopper or spider mite, it is probably another sucking insect causing the damage.
Remy

Looks to me like spider mites all over the bottom of the leaves...they attack my beans with a fury.