I don't know what it is about these cold climates. I had happy houseplants when I lived in SoCal. Occasional bug, easily dealt with. Here in the frozen northland, no matter what I try, if I bring a plant in to overwinter, the little beggar ends up with white flies, aphids, spider mites, scale.....you name it. I've tried repotting, soap spray, alcohol, systemics, topical insecticides.....nothing works. I succumbed and dragged in a few sacrificial pots this year, but all they're getting is a reprieve from the cold. I'm not even going to try to fight any bugs. If they make it, fine.