Reading up on regressing to small cell on M. Bush's website. Michael writes that under the transition period until things stabelizing you could monitor for mites - and if numbers get to high - use some non contaminating treatment. What kind of non contaminating treatments are there for varroa mites?
From Michael Bush's website.
"Another misconception seems to be that there are large losses in regressing. Dee Lusby went cold turkey, no treatments and only did shakedowns. She lost a lot of bees in the process. Many who tried the same also did. But this is not necessary.
First of all, there is no stress in letting them build their own comb. It's what they have always done. Second, it's not necessary to do shakedowns, it's just quicker. Third, you don't have to go cold turkey on treatments. You can monitor mites (and I would) until things are stable. Meanwhile you could use some non contaminating treatment IF the numbers get too high. I have seen no losses from Varroa from regressing in this manner and no increase in losses to stress related problems."