Hi Zola:

This looks like spider mite damage.  To determine if the plant is infested with mites, examine the bottoms of the leaves with a hand lens.  Or hold a sheet of white paper underneath an affected leaf and tap the leaf sharply.  Minute specks the size of pepper grains will drop to the paper and move about.

To control, hose plants frequently with strong stream of water to wash off webs and mites.  Chemical controls include azadirachtin (neem oil), horticultural oil, insecticidal soap, plant essential oils (clove, garlic, rosemary etc.) and sulfur.  I'm going to attach an article from the Northwest Pest Management Handbook that goes into further detail.  Be sure to read all labels and wear appropriate protective clothing when handling insecticides.

Bean Spider Mite

Thank you for your question,

Hi Zola:

Great follow-up question.  Overwintering depends on the species of spider mite. Some mites survive winter in the egg stage. Others survive winter as adults by hiding in garden debris or other protected areas. This is most likely the case of your spider mite. Clearing all garden debris and weeds would reduce the area they may survive in.  Come summer, water is your friend.  Spider mites love dust and dry conditions, of which we have plenty here in Central Oregon.  Over head watering will help keep the dust down and spray the leaves the moment you notice any changes on the leaves closest to the ground.

I've attached another article, this time from Colorado State University Extension that goes into a little more detail about control.

Colorado State University - Spider Mites

Best to you,