I much appreciate all the replies, comments and ideas offered here and at my website. There is so much info, I'm having a hard time keeping up and haven't managed to reply to all the helpful input. I apologize and say, "Thanks everyone!" I found the following interesting and dug a bit. >There is another vaporisor on the market from Lega Italy that might suit commercial beekeepers. http://www.legaitaly.com/index.php?page=shop.product_details&flypage=flypage.tpl&product_id=467&category_id=65&option=com_virtuemart&Itemid=68&lang=en This looks just like an ordinary heat gun blowing into a device to hold the OA. Heat guns are cheap. http://www.homedepot.ca/webapp/wcs/stores/servlet/SearchView?catalogId=10051&storeId=10051&langId=-15&N=0&Ntt=heat+gun&Nty=1&D=heat+gun&Ntx=mode+matchallpartial&Dx=mode+matchallpartial&s=true I think these links will work since I posted this from the http://\www.bee-l.org web interface. For some reason long links posted there usually work, while long links from email clients often break. I highly recommend that page for working with BEE-L for those who have never tried it. I'm continuing my drop counts and plan to give a third treatment as soon as I have the equipment at hand. My results seem to confirm that the effect is greatly attenuated after a week and substantially dissipated by two weeks. My observations also confirm that brood complicates what would otherwise be a dead-simple control. An abridged overall view can be had in seconds at http://www.honeybeeworld.com/diary/images/2011/bk10.h76.jpg http://www.honeybeeworld.com/diary/images/2011/bk10.h80.jpg and http://www.honeybeeworld.com/diary/images/2011/bk10.h7.gif The full data are summarized at http://www.honeybeeworld.com/diary/files/drop.htm The working Excel file is at http://dl.dropbox.com/u/1605400/MiteDropsDetail_3.xlsx and the full process is detailed at length at http://www.honeybeeworld.com/diary/default.htm As always, comments and criticisms are appreciated. *********************************************** The BEE-L mailing list is powered by L-Soft's renowned LISTSERV(R) list management software. For more information, go to: http://www.lsoft.com/LISTSERV-powered.html Guidelines for posting to BEE-L can be found at: http://honeybeeworld.com/bee-l/guidelines.htm