It’s a bit of both. The problem is ladybugs are so localized that disruptions to their ecosystem really messes them up. In the US most ladybugs are harvested out of a ground breeding kind of ladybug that commonly has parasites they’ve evolved to be able to fight. But other ladybugs in the rest of the country don’t have these defenses and the parasite can infect colonies when they all come together to mate and hibernate for the winter.
https://www.sciencedaily.com/releases/2011/04/110401111358.htm
Oh this is about importing asian lady beetles and not the normal native red ones from the USA?
It’s a bit of both. The problem is ladybugs are so localized that disruptions to their ecosystem really messes them up. In the US most ladybugs are harvested out of a ground breeding kind of ladybug that commonly has parasites they’ve evolved to be able to fight. But other ladybugs in the rest of the country don’t have these defenses and the parasite can infect colonies when they all come together to mate and hibernate for the winter.