Most people know of two ways of getting Oxalic Acid into a beehive: one of these being to either spray or dribble a weak sugar solution containing OA directly onto the bees; the other being to inject a cloud of micro-crystalline dust which has been formed by vapourisation into the hive.
The first method involves opening, perhaps even partly dismantling the hive, and the second requires a fair amount of energy, creates a potentially harmful aerosol which needs to be guarded against, and the vapourising equipment itself can be relatively expensive.
What I am about to describe is a third possible method of delivering OA which, as far as I know has never been attempted within the beekeeping community, and yet which could employ technology which has been well-proven within other fields.
Yesterday I took delivery of an Ultrasonic Mist Maker/ Fogger/ Air Humidifier intended for use within an incubator, but as soon as I turned it on (and it works both brilliantly, and instantly) my thoughts turned to the use of these devices as nebulisers which are commonly used for Pulmonary drug delivery in hospitals. Perhaps I should explain ...
These devices work by applying a very high frequency alternating voltage to a piezoelectric transducer or similar which causes standing waves to be formed at the surface of the liquid within which the transducer is immersed. Tiny droplets of that liquid are then formed on the crests of those standing waves, and are effectively converted there into a fine mist.
Now comes the really neat part ... It is not just the water itself which is formed into a mist, but also any chemicals dissolved in that water ! So if the transducer is immersed in (say) a 5% solution of Oxalic Acid, then the mist generated will also contain 5% Oxalic Acid. Put a gentle fan behind that mist generator, and you've got yourself the basis for injecting a fine mist of Oxalic Acid solution into a beehive, but without any need to open it ...
Is the sugar solution still needed ? Dunno - this needs testing with and without dissolved sugar.
So that's the basic idea. Plenty of info on the web about the use of ultrasonic nebulisers, especially in medicine - as it's a well-proven technology.
Any takers ? Unfortunately I'm far too busy to play with this myself, but I seriously think this has possibilities. And, if Fatshark should happen to read this - then maybe this proposal could form the basis of a PhD project, as there will be a need to run comparative tests and so forth which should produce the required necessary data.
One last thought - the Ultrasonic Misters ex China pull 1.5 to 2.5 Watts from a 24V DC supply. Compare that with the 200 Watts or so needed by a Sublimox.