The November 8th article in the Natures Nectar blog shows the benefit of a late fall oxalic vapor treatment. Make me think I should treat my hives once more and I've already treated them 3 times. Follow this link to the article.
Beekeepers Gerard and Jack applied oxalic acid this past week (week of Nov. 7th) after reading the above article. Both sent in pictures of horrendous mite drops. Their hives had all been previously treated in August.