We purchased an Oxalic Acid Vaporizer on Amazon to treat varroa mites in our three bee hives. We hate that we had to do it, but we were already seeing wing deformity in new bees in one hive. Oxalic acid seemed a cost effective (long term) and relatively safe method of treating the mites. Below are links for information about treating with oxalic acid and links to the products we used. We did not get any compensation from the manufactures for making this video.
About using oxalic acid: http://www.beeculture.com/oxalic-acid-effective-easy-on-bees-but/
More on oxalic acid treatment: http://norfolkbees.org/files/Vaporized_Oxalic_Acid_in_Hives.pdf
Vaporizer on Amazon: https://www.amazon.com/gp/product/B01LQTM7RC/ref=oh_aui_detailpage_o03_s00?ie=UTF8&psc=1
Vaporizer Manufacturer Website: http://www.blueridgebeecompany.com
Oxalic Acid: https://www.amazon.com/gp/product/B01IPL7MZ6/ref=oh_aui_detailpage_o04_s02?ie=UTF8&psc=1