A very interesting little tidbit here is the sublimation temperature of OA.   Evidently it begins sublimating at 157ºF and begins decomposing at higher temperatures.  They say at temperatures above 189.5ºF, it begins decomposing into formic acid, carbon dioxide, carbon monoxide, and water !!  I knew about the formic acid decomposition, but did not realize the temperature where this occurred was this low.

So all of us using the ProVap at 230ºF are “sublimating" at too high a temperature ?!?  I certainly MUST be if this is true which I’m sure it is.  They don’t specifically mention the “ProVap”, but they do say some vaporizers get too hot, too quickly causing the OA to decompose rather than sublimate.   Last year one of our beekeepers had a bigger mite drop with his Varrox following one of the treatments where we had previously used the ProVap and we couldn’t explain it.  Maybe this is part of the reason?  Maybe this also partially explains my seemingly continual late season mite blooms over the past few seasons !!!  (I’ve never really been able to explain this to myself…)

The authors say more research is needed into this phenomenon and there are currently no regulations in place governing the vaporizers to ensure that they are being used at the correct temperatures.   YIKES - Like I say, the first I have heard of this.  My question is where did the 230ºF number that we are all using come from???  Now it sounds like it is wrong.  The ProVap has an adjustable set point, so I will be turning it down.

(I think I might know though… I have noticed at lower temps, like around 190, not all of the OA gets used up.  When you flip it over, sometimes some of it remains in the dish above and never fully drops out.  If you turn up the heat into the 230 range, pretty much ALL of it goes.  But now perhaps learning that the temperature being too hot wrecks the dosage, the whole thing needs to be re-evaluated.  Maybe it will be possible to compensate for the unused amount at lower temperatures by adding more to the dish and being precisely consistent with the dosage application - like they say, more study necessary)

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