When to treat for IPM is also dependent on the area.  In east TN, we can
treat in July, as there is a general dearth (unless moving to the mountains
for sourwood), so we can tolerate a higher spring level.  On the other hand,
if you treat for spring, you have to start in Jan in order to get the
medications off in time for the early spring flow (which can start in
March).

One reason that the Ag Extension schedules for crop farmers have been so
popular is that it requires less thinking on the part of the one doing the
application -- just spray when the calendar tells you to.  It requires more
education (and risk tolerance) to actually assess your pest levels and only
treat when "needed".  And the whole time youare figuring out those perfect
balance levels, you are losing more of your crop than others (although
perhaps making more money overall -- something so many seem to have trouble
distinguishing).

-----Original Message-----
From: Peter Borst

If 50 (20%) turns into full blown varroa infestation by August, one cannot
skip treatment of some type on this hive. This is not a job for
statisticians, its a trial and error process.