I had similar situation at eagle point refinery w/ spraying. The bees died w/in two days and I was glad I didn't combine them. I didn't get queen which may have contributed, but i think they had some poison on them too. Just my .02. Hate when that happens. Swarms calls have been reduced to a crawl.
I was surprised to have a call; I had been getting one almost every day, and then none for more than a week. I was glad to get this one, and I'd be glad to get one more...hopefully unsprayed!
I only waited overnight to check for pesticide exposure, but I'm fairly certain they only sprayed the bees on the ground...there was no residue on the side of the trailer. I combined them with a weak hive, so they'll help it along one way or the other!