I know this is hard but this is the only scene that I really remember from this movie: it is about killer bees ('80's). This man pulls into a rest stop or gas station. Goes into this field and suddenly all these bees start attacking him. He runs back to his car and even though he gets his window closed, the bees come in from the vents. They kill him and just fly back to the field. It was in the 1980's maybe even the 1970's but I doubt that

Here's one possibility:
The Swarm (1978)

Here's the plot summary:
http://en.wikipedia.org/wiki/The_Swarm_(film)


Other killer bee movies are:
The Deadly Bees (1966)
http://en.wikipedia.org/wiki/The_Deadly_Bees

Killer Bees (1974 TV movie)
http://en.wikipedia.org/wiki/Killer_Bees_(1974_film)
This one actually is more of a horror story, with the bees under someone's control.

The Savage Bees (1976 TV movie)
http://www.imdb.com/title/tt0075166/?ref_=fn_al_tt_1
This one is noted for ending up in the New Orleans Superdome. I think they find a Volkswagen can keep the bees out.