W.G. Miller pointed out that formic acid is not registered for varroa
control in the U.S., suggested collecting feral bees for varroa
resistance, and wondered what other North American insects are hosts for
varroa.
Other hosts? My understanding is that although adult varroa may rarely
be found on beehive-visiting insects (wasps, bumblebees) and even
rodents (or beekeepers), reproduction only occurs in honey bee brood. So
there is no reservoir of varroa outside of honey bee colonies, but
there's a small possibility of varroa transfer by things other than
honey bees (insignificant in areas where varroa is established).
Yes, formic acid is not registered for bee use in the U.S. Why? As a
generic product, it is less attractive than a proprietary product like
Apistan, to a company who wishes to market it. The costs of registration
might be borne by such a company, registration obtained, but then
beekeepers might simply use the industrial product. Where's the profit?
(This is just an observation, certainly not a suggestion that
unregistered products should be used if someone personally justifies
it.) The U.S. Office of IR4 (a program to register pesticides for minor
uses or industries) has been working for at least 6 months, on the
registration of formic acid for bee use. I have been dissappointed to
see apparently uninformed or misleading comments in the advice column of
ABJ regarding formic acid. That it is unregistered and therefore should
not at the moment be used in the U.S. is clear. Trying to reinforce the
situation with alarmist rhetoric is ... dissappointing.
The twice a year Apistan option?
The problem with constantly using (even at recommended rates) a single
active ingredient against a pest (or even similar products with near-
identical mode of action eg? Apistan/Bayvarol), is that it sets the
stage for the pest to develop resistance. Rotation of control products
with different modes of action is a strategy to prolong the (years of)
effectiveness of each of the products.
None of the products I consider effective against bee mites is
absolutely safe or fool proof. Some ingredients and formulations have
advantages over others, especially in certain situations. I hope and
trust that a process that includes thoughtful planning and
evidence-based, rational consideration of the options, will give us the
best chance to deal with varroa in the long term.
Are feral bees more likely to be varroa resistant?
There's an ABRC abstract in Dec '94 ABJ, where "tracheal mite survivor"
feral bee stock was compared to others and found no more resistant than
unselected stock. Varroa resistance is even less likely to be found,
than tracheal mite resistance, so I wouldn't expect much from this
strategy. I'd guess most swarms or feral colonies in varroa areas, are
recent escapes from managed, treated colonies.
Eventually, yes, a symbiotic relationship between bees and varroa is a
good objective. Select the bees? select the mites? natural selection?
Thanks for the comments
Kerry Clark, Apiculture Specialist
B.C. Ministry of Agriculture
1201 103 Ave
Dawson Creek B.C.
V1G 4J2 CANADA Tel (604) 784-2225 fax (604) 784-2299
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