I am an experienced beekeeper and consider I take good care of my bees, 5+ hives on the NW coast of Scotland and up to a few years ago the area was varroa free. Yesterday after a decent stretch of low temps I applied OA by sublimation, I do this every winter. The resulting 24hr drop was quite surprising given my regular monitoring and management of the dmd. Throughout the brood rearing period of the year I place the yellows under maybe every 4 weeks or so and chart the drop. I see the usual trends and suppress the varroa with icing sugar which has worked well. Going into this winter the dmd was 2/3 per day. Today after yesterday's sublimation I had some dmds up in the 90s and 70s, quite a surprise, other hives were up of course but in the expected range after a sublimation.
I have been following Sussex Uni's recent papers on the use of OA and how sublimation is the best method of the three. If as I am lead to believe I have killed off ~97% of the phoretic varroa I am trying to calculate if and when I should apply another treatment in an attempt to remove as much as possible before the Q starts laying. Popular current thinking is ~6 days after first treatment and then 15/16 days after the second treatment which seems logical.

Would anyone like to comment on the expected effectiveness and timing of this program.

Thanks,

M