Matt, HEre in the south western corner of British Columbia, we have had some major losses of colonies as a result of Varroa (probably in combination with A. woodi). Many beekeepers did apply their apistan strips in the fall for the recommended treatment period and pulled them out. But consider that the mild weather conditions allowed the bees to maintain some brood longer in the fall, and with some limited flying weather allowed for re-infestation and mite development. In early spring (jan-feb) the bees became broody again especially when beekeepers added a nice pollen patty. During the spring months of 94, we saw massive bee kills. The varroa mites that had survived the mild winter had the opportunity to expand enormously by feasting on all the young bee brood. By April and May, many colonies were primarily comprised of old, wintered bees, and collapsed. We now recommend beekeepers apply a single strip to a two-supered winter colony in early February and leaving it in for a month. Perhaps in the future such a second treatment may not be necessary when high rates of re-infestation (by feral and non-treated colonies) have levelled off but for now such an 'interim' treatment may be a good precautioonary measure. So far, this recommendation has not been extended to producers in the interior (of BC where colder climates prevail) because the much longer, broodless period limits Varroa's ability to winter as successfully. regards, Paul van Westendorp [log in to unmask] Provincial Apiarist British Columbia