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Alberta Beekeepers Survey Results *From the Aug 31, 2009 Issue of
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Alberta beekeepers have struggled for the past three years, suffering
from 30 per cent losses of their colonies each year. Most of these losses
occurred during winter, which was an expected chain of events in case of
failure of pest control, but beekeepers still were taken by surprise. It was
fast and losses were far above their expectations.
.
"An annual survey was conducted to determine losses and to study possible
causes of the reported high winterkill," says Dr. Medhat Nasr, provincial
apiculturist with Alberta Agriculture and Rural Development. "The *2009 Bee
Winterkill Survey* confirmed what 2007 and 2008 surveys established: 28 per
cent of Alberta bees were killed and 13 per cent of the colonies that
survived were weak and non-producing. Throughout the province, 54 per cent
of beekeepers reported losing one-third or more of their productive colonies
in 2009 due to winterkill and weak colonies. However, 14 per cent of the
beekeepers reported only 14 per cent winterkill and weak colonies."
Study results from winterkill of bee colonies survey indicated that a
monumental shifting in beekeeping management of varroa mites occurred in
2007. Basically, Apistan and Checkmite+ lost their efficacy against varroa.
"This was a big blow for Alberta beekeepers," says Nasr. "In addition,
available alternative treatments when applied, did not provide sufficient
control due to cold temperatures. A new nosema species, *Nosema ceranae* was
also found in Alberta. The distribution and prevalence of the new species
are unknown. Finally, a very long cold winter followed by a cold spring
aggravated the problem resulting in high winter kill and weak surviving
colonies."
Laboratory analysis of hundreds of honey bee samples showed that honey bees
were unhealthy. Sixty per cent of survived colonies were infected with
varroa rates above the economic threshold (1%) and 50 per cent of bee
colonies suffered from nosema with infestation levels above one million
spores per bee. Overall, 30 per cent of sampled colonies endured high
infection of both varroa and nosema that could cause severe setbacks to
bees' health. Tracheal mites were at high levels in 10 per cent of the bee
colonies. These reported infestations with varroa and nosema and, to a less
degree, tracheal mites compromised the health of honey bees. Moreover, long
and very cold winters only exacerbated the problem leading to higher than
average winterkill.
"To begin turning the tide, in response to reported failures of Apistan and
Checkmite+ in controlling varroa mites, beekeepers were advised to change
their pest management practices," says Nasr. "As a result, almost 85 per
cent of beekeepers started to apply formic acid more frequently for varroa
and tracheal mites control. The formic acid application time was also
shifted to spring to better meet temperature requirements for achieving high
efficacy rates. Some 23 per cent of Alberta beekeepers also resorted to
oxalic acid applications in early winter and early spring when bee colonies
are broodless for varroa control."
The *2009 Bee Winterkill Survey* can be viewed on Alberta Agriculture and
Rural Development's website,
*www.agriculture.alberta.ca*<http://www.agric.gov.ab.ca/app21/rtw/index.jsp>by
searching
*2009 Bee Winterkill
Survey*<http://www1.agric.gov.ab.ca/$department/deptdocs.nsf/all/prm12803/$file/bee_survey_2009.pdf>.
Additional information on pest control research and what Alberta beekeepers
are doing to protect their industry will be featured in an article in next
week's issue of Agri-News.
Contact:
Dr. Medhat Nasr <[log in to unmask]>
780-415-2314
--
Juanse Barros J.
APIZUR S.A.
Carrera 695
Gorbea - CHILE
+56-45-271693
08-3613310
http://apiaraucania.blogspot.com/
[log in to unmask]
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