This idea was stolen, fair & square, from Randy Oliver. Folks living outside of Boise might want to follow the methodology in the ScientificBeekeeping.com article instead of using this chart. The graph illustrates the treatment periods in color. Light blue is the thymol application period, formic acid is pink and hop beta acids are shown on the tails of the calendar during the broodless period. In the case of thymol, the dates assume that thymol is on for 4 weeks and the supers can go on right after the product is removed, per the label.
Formic acid is bounded by temps. The color areas show the application period, and the dates assume a three week application window. The application period is only 7 days. This may be a little obtuse. Check it out and send any questions. The intent here is that we can have a tool for the beginning beeks to use when trying to figure out when and with what to treat for that despicable, nasty varroa mite.