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Alberta Beekeepers Survey Results | |
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From the Aug 31, 2009 Issue of Agri-News | |
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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.
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"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 by searching 2009 Bee Winterkill Survey. 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
780-415-2314 |
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For more information about the content of this document, contact Medhat Nasr.
This document is maintained by Rita Splawinski.
This information published to the web on August 26, 2009.
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