>http://beenatural.wordpress.com/legacy-beekeeping/oxalic-acid-evaporator/

Dennis has some good material there.  His designs make sense and should work, 
and I have considered his ideas.  One problem for me is that although I do have 
auger holes in all brood chambers, my hives are plastic and I suspect the copper 
tubing would melt the auger holes.  I am also uncertain how uniform distribution 
would be.

Heating individually with a torch is feasible, but the temperature control is not 
good and the job is hands-on, and also dependant on weather and wind.   

Maybe I am obsessing about controlling temperature and maybe the 
evaporating material will hold the temperature until it has all gone, but I have doubts.

I notice that the page is from 2009 and Dennis was saying how he was using 
"natural cell" and "mite tolerant bees from small cell hives" and not treating 
routinely.  Some time later, he reported very high losses here on BEE-L.

That mirrors my experience in depending on "mite tolerant bees" and confirms 
the oft-repeated observation from those who see a lot of operations.  

That observation is that ignoring varroa levels does not result in immediate losses, 
but after several years, the assumption is that the various diseases and viruses 
abetted by varroa build up to where a sudden collapse occurs even if the levels 
are below supposed threshold.  Three years typically can elapse before problems 
suddenly avalanche.

Pete mentions this from time to time and is usually met with disagreement from 
those who have been getting away with allowing varroa free reign.

             ***********************************************
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