> From:    allen <[log in to unmask]>
>
> IMO, the next Big Thing will be oxalic acid evaporation.  It has a good
> report.  It does not seem to hurt bees, leave a residue in honey, or
> endanger the operator if used with care.  It can be applied at a time of
> year when the bees and beekeeper are not occupied with important tasks, and
> costs 2c per colony per treatment.

Well, I wouldn't bee all that optimistic about it yet. The research done is
mostly in central Europe with milder climate than ours. What has been shown
is that treatment differs up here compared to lover latitudes (in trickling
oxalic solution). So far I don't believe we should hope for more than 90%
efficiency, that means other  treatments have to be applied too during
spring/summer to keep the mite numbers below dangerous levels. Another
treatment of oxalic in spring will not do much good as almost all mites are
in capped cells and will not be affected by it. To remove drone brood or
something else is needed too.

Remember it's not the mites that's the real problem, it's the different
virus it's a vector for. Important for wintering is that bees going into
winter are not raised in a colony with heavy virus infection. Those bees
will have smaller chance to survive through winter. So what is important is
the status of the colony at the time the winter bees are produced,
august-september before any oxalic treatment is possible. The longer the
summer, the smaller the chance autumn oxalic treatment will be enough.

Another thing about vaporizer is it's time consuming. It takes several
minutes for each hive, and then the hive should be kept closed for some
time to allow oxalic to spread inside. When comparing to trickling sugar
syrup with 3,2% oxalic it's a big difference. Doesn't matter much for the
smaller beekeeper, but is important for many bigger operations. I realize
this after done both treatments.

Hoped to get some figures to compare methods, but winter is early and bees
in tight cluster so I doubt there will be much info from my experiment
until next autumn when I'm going to start earlier. Unless I can get
something from the wintering. Oxalic like other toxic substances will
affect the bees wintering. There might be some measurable difference in the
spring. Time will show...

--
Regards

P-O Gustafsson, Sweden
[log in to unmask]  http://www.algonet.se/~beeman/