Joel and others,
Waiting until broodless is the ideal time to treat to
"get all mites exposed", however, if we did that in Tennessee, we would
probably be too late.  Treatments should not be based on calendar year.
Treatments should be applied before the number of Varroa reaches a
critical level. One thing I try to remember is that we should
overwinter with healthy bees that are not "punched full of holes"
by mites.  If we delay treatments, the bees, although treated may
already be damaged sufficiently to not survive the stress of
winter.
 
John A. Skinner           218 Ellington Hall
Extension Apiculturist    University of Tennessee
[log in to unmask]          Knoxville, TN  37901   (423)974-7138