Todd has a point

> I bought a Heilyser vaporizer late last fall
> (from Canada), and found it cheap (around $65 U.S.), fast (about 3 minutes
> per hive - no need to open the hive),

The vaporizers that work with propane torch are faster than electric ones. There is one problem with them. You should not heat oxalic acid too much (above 200 degrees C) because much of it changes to water.  The best temperature is between 100 - 200 C. In this temperature the gas that comes from oxalic acid is mixture of water, formic acid and oxalic acid. The warmer it gets the more oxalic acid breaks to water, and the efficacy goes down. Electric heaters warm up slower and don't overheat so easily.

The torch ones I have seen in Finland have had a foot pump, a 1 liter steel chamber for oxalic acid and a thermometer to follow the temperature in the chamber. Beekeeper uses a torch to heat the chamber with about 20 - 50 g of oxalic acid and pumps the vapour into a hive and then continues to next one until no gas comes out. They have been in use for more than 10 years.

Its crude, but it works. I don't advice everyone to use this mainly because there is no cntrol over the dose how much you get acid vapuor in hive. The beekeepers just ' pump until full'  But it looks like the bees can handle it most often. Also the need of a respitator and eye protection is obvious.

The average beekeeper here has 10 hives, the investment is too much compared to tricling.

Yes,  you can vaporize several times without negative effects to bees. But it is very ineffective when there is brood in the hive. Thats why we use thymol of formic acid in early fall treatments instead of vapour. Late fall  treatment with oxalic acid tricling or vaporizer. More than 95 % of our beekeepers choose tricling.  We have had no reports about queen problems with tricling.

Ari

Project Manager
Finnish Beekeepers' Association
www.hunaja.net

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