I have 2 hives and this is my 2nd year beekeeping. This year I decided to try sugardusting the bees for varroa treatment for 6 weeks. Today would have been my final day to treat. When I opened the weaker of the two hives I saw a good number of partially developed bees- white pupae - in the cells that had partially chewed off. And amidst all the bees, there were also a number of workers I noticed with deformed wings. I think that despite the sugar dusting (I don't think I'll try that method again) they are severly infested with varroa.
My question is this: is it too late to treat the hives with something stronger, like Mite-Away Quick Strips or formic acid? It is mid-Oct and I live in the NC mountains - it is now getting pretty cold at night and days are regularly in the 60's. One thing of consideration as well - this hive has been weak all year. This hive made no extra honey during the flow, and ate what they had made within 6 weeks. I've been feeding it non-stop for weeks now (since mid- Sept). Checking in the hive today, I noticed only 6-7 partially filled shallow frames of stores (though I didn't inspect the deep). The other hive has plenty of stores- the suggested 45lbs, and this one I'm afraid doesn't even have 20 lbs.
I'm afraid this hive is not going to make it - can I do anything for them?