Lynn

Do you see a lot of aphids on the stems near the leaves?

Can you post a closer-upper view?

Susie

Mosaic virus transmitted by white flies often causes leaf curl in beans .

" Silverleaf whitefly. Several predators and parasites naturally attack the silverleaf whitefly, including ladybird beetle larvae, green lacewing larvae, and the parasitic wasps Encarsia species and Eretmocerus species. Natural control of whitefly populations can be encouraged by avoiding the use of broad-spectrum insecticides . "

From this link :

Here is a link that might be useful: Profiles: Snap Beans