I am vety new to this beekeeping thing, but have wiped down the iinside if hive bodies with a mix of tea tree oil, rosemary and thyme, more as a way to inhibit the bad stuff, not sure if it made a difference. I also made a bee tea with 1:1 syrup to which I added thyme, dandelion tea and chamomile tea. They seemed wait for it in the cold months and it seemed to help my nucs multiply like crazy....i kind of liked the idea of the hernal tea, offered in a hanging chicken feeder to them, once the nectar started they ignored it.
Andrea