Waited for a cool night so I could get the plants into a trash bag with most of the whitefly still resting on them. Cleaned up all the leaf litter from around the plants too, as it is probably full of disease the insects have spread. Either the cool weather or my hand-removal is helping- I found less whitefly on the broccoli plants than before. I wiped undersides of the foliage again and found fewer whitefly eggs/larvae than before, and only four caterpillars. Also some white specks on the yellow traps, so maybe that helped some too. I'm going to rinse them off and re-apply the sticky stuff.
I am going to smother this plot (where the green beans were) with shredded cardboard, compost and leaf mulch, and hope for better luck next year. At least the soil looks good- rich, black and crumbly- and there's lots of worms. I disturbed at least half a dozen this morning. They look healthy. Crawl away quicker than you'd think a worm can move.