I’m using a, for me, new tool in my effort to combat varroa in my colonies, apiguard. You place a “serving” of apiguard on top of the top bars of the frames and leave it there for two weeks and repeat.
From the Apiguard website :
Worker bees climb into the Apiguard tray, remove the gel as a hive-cleaning behaviour and distribute it throughout the colony. The gel sticks to the bees’ body hairs and, as the bees move through the hive, particles are left throughout the hive. The worker eventually throws out the gel it is carrying, but the traces remain until they too are removed later.
The gel acts like a slow thymol release agent. Thymol is a naturally occurring substance that has proven to work as an anti varroa agent as well as being an antimicrobial and fungicidal substance. Seeing my earlier experience with formic acid, this perhaps is a good alternative. Although I forgot to place a bottom board in the hives to see the varroa drop, thus making it hard to compare it to the formic acid treatment. But perhaps I’ll see less varroa in December when I treat with oxalic acid because of this treatment.
You do need to be done with your honey harvest because the thymol will also dissolve into the honey giving it a distinctly unpleasant taste. You should also not feed the bees while giving this treatment because the bees will be to busy with storing the feed syrup to disperse the thymol gel.
Otherwise Sif and Artemis are looking good. Next on the todo list is judging the fitness of the colonies in the light of winter survival. Will need to asses their size and food supply to estimate how much feeding they will need.