I heard that there were problems this spring in the use of  wintergreen
and other oils used in hives in California almond orchards. The hives
which had the oils were robbed out by other hives which were not treated
because the the bees were disorganized and did not recognize their queen
as the oils masked her pheromone. It may not be true, but it does track
with some who found a new queen was not accepted when scented oils were
present in the hive.
This is only rumor and would appreciate hearing from anyone knowing the
facts.
Bill Truesdell
Bath, ME