I treated the hive with the mesh floor and tray on 30th December. Until then the typical mite drop was about 3 per day.
On 31/12 there were 17 mites on the tray; 2nd Jan 21; 3rd Jan 11; 4th Jan 26; 5th Jan 18, 9th Jan 24, 11th Jan 6. So after a surge, the drop has returned to about 3 per day.
What does this mean? The short answer is dunno! As the mite drop is now the same as it was before, maybe it has been a waste of time, despite about a hundred extra mites having been killed.
Why has the drop dropped back to 3/day so suddenly? Have most of the remaining mites found brood to hide behind and reproduce upon? Have the bees got rid of all the oxalic and now aren’t bothering (although one of today’s mites was dented as if by bee mandibles)?
I’m undecided at present what to do next and would welcome suggestions. I might repeat the vapour treatment and see how the figures compare. Alternatively, I could give a trickle treatment and compare. Anyway, it will have to wait for a while as I’m about to take a holiday.