 like nationally every year because of these mice the primary driving factor is varroa destructor there are other things that are going on and i don't want to make it seem like there is a single problem it's multifactorial but what we do know is that these parasites are at the center of the web of problems because pesticides are one issue but because the parasite literally feeds on the tissue that breaks down pesticides pesticides are a lot more deadly when they are around