white mold on bush beans

the last 2 years I've had white mold on my bush beans. yes, I moved them to a another sqft garden this year, 100 ft away from last year's garden. everything I read says that "over crowding" is the main problem. I'm following the sqft spacing guide.
any thoughts on this and also any fungicide that might be used? 
thanks,
glenn

Is this what seems to be happening?

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

yes pretty much, on a much smaller scale. I will try to move the bean patch again next year and plant them with more space than the SQFT Gardening guide. for now, I've pulled the "moldy" ones and have picked what I can. I've discarded them off the property. I don't think at this stage any fungicide would be helpful? 
thanks for the reply.
glenn

When you say patch, it sounds like you have adjacent squares of beans next to each other. You might want to try switching to a checkerboard pattern and having some other plant(s) (maybe scallions, carrots, radishes, lettuce, or spinach) in the alternate squares so that you have a more open planting that traps less moisture. A mulch, applied after the beans come up, but before they flower, that drains well and dries quickly, might also help.

From what I'm reading I think it's too late for a fungicide. It sounds like the fungicide is best applied when the plant starts flowering, and even then it sounds like the fungicide route doesn't have a high success rate for dealing with this particular fungus.

thanks,
yes it's too late for chemicals.....I have several 4x4 and 4x10 foot gardens on the property. the one that had white mold last year, was a 4x10 that is about 150 feet from the 4x4 I planted in this year. In the 4x10 from last year, I discarded the plants, dug out 8 or so inches of soil mixture and dumped it in the woods a hundred or so yards away from any plantings and replace it with new mix. This year, I have lettuce and eggplants in the 4x10, with no sign of white mold. I think I may plant less beans per sqft next year in a 4x4 away from this years problem 4x4. I'll also discard all plants and soil mix and start over with another type of planting next year in that garden. 
thanks again,
glenn

Eggplants and lettuce aren't as susceptible to the Sclerotinia sclerotiorum white mold as beans are, particularly if the eggplant fruit aren't resting on the soil when the cool, damp conditions occur. Although the mix in the 4x4 is likely 'contaminated' now that it's had a crop of infected plants, and shouldn't be used for beans next year, the problem is likely airborne since it affected a different bed this year. You can't stop the airborne spores, but having more space between plants changes the environmental conditions (making them dryer and warmer) so that the airborne spores are less likely to survive and 'sprout' on the plants.

It looks like solarization might help 'decontaminate' the 4x4 mix if you'd rather try something other than removing/replacing part of your mix. The articles I've read indicate that Arizona temperatures without solarization are sufficient, but solarization does have an effect in cooler areas. One article said 8-weeks during the summer - if you only had beans in that bed, and they are done you could remove them (and throw them away - don't cold compost them), cover the bed with a plastic sheet, and probably get enough high-temperature time before the weather cools. If you can manage two layers of plastic that should increase the temperature even more. Here's a link to a forum comment quoting a now missing page from an ag resource site about how to do two layers:
https://squarefoot.forumotion.com/t19508-time-to-solarize-and-kill-nematodes#223579

thanks very much for the info. makes sense.
glenn

I corrected the link in "Time to Solarize and Kill Nematodes".

The new UC Davis link is: http://ipm.ucanr.edu/PMG/PESTNOTES/pn74145.html