> >The question now is if 2 g. in a liter recommended for drench on the Canada label is a higher dose than when fed in 2 gallons of feed or the same.
Hi again Bob,
There are 21mg active ingredient per gram of Fumagilin-B. So in 2g/L,
there would be 42mg a.i. per liter.
Compare that to the 95g of active ingredient per gallon of heavy syrup
when prepared by label (1 bottle in 100 gal).
Higes found that 30mg a.i., fed 4x, weekly, in only 500ml (about 2
cups) of syrup completely eliminated N ceranae. However, when I
drenched bees with the same amount, 4x, weekly, it did not. So
apparently drenching may not get the dose into the bees' guts as well
as feeding syrup, and a higher dose is required.
Here is some recent information for the List:
I've been corresponding with both Dr. Higes, and Antonio Pajuelo of
CONSULTORES APÍCOLAS http://www.pajuelo.info/.
These two researchers disagree as to the seriousness of N ceranae infections.
Dr. Higes feels that colonies can handle moderate infections as long
as the queen is able to sustain egglaying to offset the continued
premature death of infected foragers. Collapse may not occur for
months, or maybe more than a year after the colony becomes infected.
A new young queen, or supersedure queen, may give the colony a "second
wind," but if the queen begins to fail, the colony will succumb. His
recent studies have found that during this period of inapparent
infection, that colonies may exhibit a 50-70% loss of honey
production.
On the other hand, Pajuelo feels that most of the Spanish collapses
are caused by the drought in Spain. He cites three labs that do not
find unusual mortality from N ceranae when colonies receive adequate
nutrition. Pajuelo suggests that the Spanish Síndrome de Desaparición
de Colmenas, SDC is caused by a combination of three factors: poor
nutrition, in-hive miticides, and high varroa levels.
So there you have it--clear answers from the experts, in complete
opposition to each other! And yes, Bob, since so little is currently
known about N ceranae, and with so much research being done, anything
that anyone puts into print will likely be dated within weeks--this
post included!
Randy Oliver
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