Lupester, you're correct. In fact, the various fields contained either white, or purple blooming beans. And if memory serves me, both types, determinate and indeterminate, were planted by different farmers. Problem is, around here they have a serious problem with a particular type of worm. So they aerial spray a few weeks after bloom starts, IF they see indication of the worm. If they don't spray, they lose the crop. First year I had bees on the beans, it was like a door slammed shut on the flow. I found out they had all sprayed. I lost three days worth of field bees. Colonies recovered just fine, and overwintered very well.
This past year I determined to avoid a pesticide kill. So the day before they all sprayed, I moved the bees several miles away to a bean field on a river, where that farmer never sprays. Got nary a lick of honey off that field. Not sure what I'll do this year. Gets real frustrating.