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