Yet another mystery movie...
But first, re: the movie that sounds a lot like "Children of the Corn" - it's been a long time since I've seen it, but I vaguely remember another killer children movie called "Who Can Kill A Child?" - took place on an island, as I remember, though. Probably not it, but worth a shot.
So, mystery movie: like most here, this one goes back a looooong time... probably close to twenty years since I saw it, and even then I only caught the second half of it. Never knew the name to begin with.
It might have been a road movie or something. I remember a couple - husband and wife, maybe - travelling, driving, and they keep being hit by disasters, yet remain curiously unaffected by them. Some scenes I can recall:
An emptied out city (NYC maybe?) - the male lead has an encounter with a disheveled businessman of some sort, who's freaking out. There might have been a run-in with a cop, too.
The couple driving through a swarm of some sort - bees? Locusts?
A flood, but their house - or someone's house - remained on a little island to itself, unharmed. They would get to and from the main city via rowboat. This was towards the end of the film, if I remember right.
The leads finding themselves in a junk / antique shop in the middle of nowhere, and finding something in the shop that one of them had lost earlier in the film (earlier than I tuned in) - the item had something to do with baseball (a card or a glove, or maybe a baseball itself) and was swept away in some kind of storm, I think.
Anyway - swarm, floods - it had some kind of maybe biblical imagery, and a post-apocalyptic, yet laconic feel. I'm guessing late 70s to mid 80s. Hopefully a lightbulb goes off over someone's head.