Last year, I had one cooler full of my homegrown Virginia get infested. It was under my bed, and I woke up feeling like I was covered in bees. They had eaten up the tobacco to dust, and were crawling through my bed... bitey little fuckers.
I had no idea that I could freeze them to death. I had worried about them getting into the other coolers. But, so far that was the one and only batch to get infected. My humidor was in the room as well as a couple of plastic tubs full of homegrown tobaccos.
But, so far, they only ate up that one batch of reds. So, I guess they had survived the intensive heat of color curing, and only wanted that one type. I keep my Virginias sorted by color and variety, and the rest by variety.
Vacuuming them up and changing the bed was all it took to get rid of them completely... as far as I have seen.