Powdered sugar in grease patties:  Powdered sugar works just fine instead
of granulated sugar.  I like it much better than granulated sugar because
the patty doesn't break up during hive manipulations, and less is wasted on
the bottom board.  While the bees have been reported to not digest the
cornstarch powdered sugar contains, you're not feeding very much powdered
sugar to a hive.
 
While Dr. Sammataro's research showed that leaving patties on all summer
resulted in fewer Tracheal Mites (HBTM) than only using them in the spring
(for AFB control), her research did not consider the sometimes wide
variation in brood survivability between hives due to queen quality
problems and other variables.  These alone may have caused the reduction in
HBTM between the control and treated colonies.  I personally have not used
any treatment for HBTM except for what small impact my TM grease patties
may have.  I use the TM grease patties only during the spring dearth period
and then I use a half patty in the fall after supers are removed if it will
be unusually warm allowing for extended bee flights and robbing of weak
diseased hives.  My HBTM percentages have ranged between 5-15 percent in
the spring and fall for the last ten years.  It is obvious from studying
the colonies, and the bee behavior, that brood patterns range from what are
called excellent to spotty.  From my past studies I know that even an
excellent brood capping pattern may cover a 35% brood survivability!!!  Low
levels of brood survivability, or any environmental or managerial
occurrance which interrupts brood cycles, will keep HBTM and Varroa mite
levels low.
 
If grease patties are indeed significantly effective against HBTM they
probably wouldn't need to be used all summer and certainly not year round.
If we knew how long it takes to get the grease in the patty distributed
throughout the bee cluster on the surface of bees, and how effective it is
in reducing HBTM reproduction over time, one could calculate the number of
brood cycles necessary to reduce mite populations a specific percent.  The
ideal pest control should eliminate a pest within several brood cycles of
its host.  It shouldn't take all year to do so.  That just wouldn't be good
pest control policy.
 
My judgement would be to use the TM patties with powdered sugar during the
spring for foulbrood control (before supers are added), and if you take
supers off in mid to late August, put on another patty without TM, unless
bees will rob AFB at that time of year.  Do not have patties in the hive
all winter.
 
James C. Bach
Yakima WA
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