I've not had any random crop deaths due to fog, but it does perhaps explain why sometimes you get a lot fewer mutations than expected, even with resetting.
I'm guessing that probably we'll find that some crops are more resistant to fog damage, just as some survive better without water for a period of time. Flowers in general seem to just LOOK for an excuse to keel over, IMO.
So much depth in this game; if only it had all be explained to us better...!