CCD itself is hard to pin down, not only as what causes it, but what is properly diagnosed as CCD in the first place.
There have been large, widespread bee die-offs n this country periodically for more than a century.
Not being expert on this last one, nor on this most recent report, I do notice that on one map the fly seems to be found in California, but other information suggests it's common nationwide? I'm not up to speed yet -- will never be completely, I'm sure.
If you’re right about California, Napa/Sonoma Valley better be ready.