I have a highly populated hive in my apiary. Actually, I have several but one in particular isn’t just highly populated, they are mean – aka, “The bitches”. Late July into early August is the best time to test for varroa mites. I tested most of my hives at the end of July. However, I neglected to check “the bitches” because, well, they are highly populated and they are the meanest. I figured, “how could they possibly have a high mite count”, so I didn’t test them until today. To my shock, they have a 4% mite count. In general, you want to have only 1% or less. This is not good! 
I’ve been told, that when it is this high, the chances of the hive making it through the winter are very slim. So, I will treat them and hope for the best. I will have to treat them again in December, but it will be a long winter of me worrying about them. Even “the bitches” need help too.