Asian bees are perfectly capable of removing and killing mites as is. So are some breed species of European honey bees. There have been found abandoned apiary in France where the bees have evolved to groom themselves and remove the mites.

The bees does need to evolve, but not to the point of producing venom. Mechanical mite removal works equally well.

I was rather thinking of bees developing the ability to shoot tiny lasers to cook the mites off like popcorn. Or maybe a static discharge from their wings rubbing together, like a natural taser.