A few points that have not emerged in the recent interesting
discussions:
Dr. H. Shimanuki reports that B.larvae collected from current (1993)
infected hives (U.S. I suppose, but I don't know how wide was the
sampling) was NOT more resistant to oxytetracycline, than B. larvae from
scales collected in 1924.
(it's no reason for undue complacency, but until other evidence is
presented, it's a measure of the current situation).
There have been comments about EFB infected hives that didn't respond to
oxytetracycline. I had one like that many years ago, and after a
reasonable period of treatment (3 weeks) I thought I'd better destroy
this "resistant strain". I took a closer look and noticed that, although
there were still larval remains, there were no recently-dead larvae.
That didn't solve the dilema, but then I happened to pick up a swarm too
small for self-sufficiency, added it to the weakened EFB hive, and the
next day, there was no sign of the EFB. Down with non-hygienic stock!
The "When Bugs Fight Back" compendium of articles by Pullitzer prize
winner Mike Toner from the Atlanta Chronicle, makes some interesting and
perhaps justifiably alarming points. It's still journalism,( oops I
didn't mean that to sound disparaging, it's just that some tough digging
would be necessary to decide how alarmed one should be). The phone order
worked fine, there was no charge for the article. Thanks to Tom Sanford.
Allen: the woman who impressed you was Dr. Christine Peng from
U.California Davis. One of her points was that oxytetracycline has
sublethal effects on brood development (perhaps slightly lengthening the
development period). She had encouraging results against B. larvae, from
another antibiotic called tylosin. (Linoleic acid is also "waiting in
the wings" against AFB).
Strategies for sustainable management of AFB and varroa (and other bee
diseases) could certainly use some more consideration, better sooner
than later.
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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