Bayer and other biggies produce the miticides in use now--so there is a market for sure. Trouble is, I always suspect a lot of these companies don't want to create anything too effective. I mean, if mites were wiped out--say, because they couldn't reproduce--then bye-bye profits, ya know?
I just fed my girls syrup with Honey-B-Healthy. We're having a few sunny days in the 50s--and 60s this weekend, so I'm looking forward to them consuming a whole lot more syrup, and all of it will have essential oils.