A Look at Canadian Honey Bee Overwintering Losses

Thursday 4 August 2022

Every spring, beekeepers are asked by the Canadian Association of Professional Apiculturists (CAPA) to report on their overwintering losses. The results of the 2022 survey are in! Last week, CAPA released their “Statement on Honey Bee Wintering Losses in Canada (2022),” read on for a brief summary of the results. 

A Look at Canadian Honey Bee Overwintering Losses

The CAPA “Statement on Honey Bee Wintering Losses in Canada” is an annual report published to consolidate information that CAPA and our Provincial Apiarists have collected regarding the overwintering success of beekeepers across the nation. Reporting overwintering losses to CAPA continues to be a valuable tool for seeing trends in beekeeping operations nationwide. This year, results are based on the responses of 626 Canadian beekeepers with a total of 480,983 hives.

Figure 1. A modified table of survey parameters and preliminary honey bee colony mortality (2021-2022) to highlight the results of the Atlantic Provinces. 

The 2021-2022 winter was a difficult winter for Canadian honey bees. The national overwintering loss was 45.5%. This is nearly double the percent loss reported the winter prior, at 23.2%. Between provinces, there was a large range, from 15.3% to 57.2%. Overall, Atlantic Canada fared better than most of the nation, with Nova Scotia, New Brunswick, and Newfoundland being the only three provinces to report losses below 30%. Prince Edward Island suffered higher losses, at 51.9%. 

The CAPA statement not only reports figures, it also asks beekeepers to indicate the possible causes for their losses. This year, beekeepers were more consistently responding with the same causes. Ineffective varroa control, poor queens, and weak colonies in the fall were the top reported reasons for colony loss, nationwide. Furthermore, the provinces which had the highest losses all ranked “ineffective varroa control” to be their number one reason for colony death. For Atlantic Canada, specifically, the leading reasons for loss were less consistent, with ineffective varroa control, weak hives in the fall, and starvation being the top concerns. As such, beekeepers preparing for the upcoming winter this season should consider addressing these as priorities in their summer and fall management practices. For example, it will be important to test for mites and subsequently treat; hives should be supplied with adequate food resources to make it through the winter; and now is a good time to consider how to best manage weak colonies. 

Figure 2. A modified table of the top four ranked causes of honey bee colony mortality to highlight the results of the Atlantic Provinces. 

The 2022 statement places particular emphasis on varroa mite control. According to the survey respondents, Apivar® is the number one chemical treatment used against varroa mites across Canada. It is popularly used in both spring and fall treatments. As such, it is inevitable that varroa mites will develop resistance to amitraz, the leading ingredient in Apivar®. Unfortunately, there has been evidence of this beginning in some provinces. This means that monitoring for mites both before and after treatment is more important than ever. Please see the ATTTA factsheet on Summer Disease and Pest Monitoring in Honey Bees for detailed information on how to monitor varroa mites in your colonies. Monitoring in the summer can be critical to knocking back varroa mites populations before fall, when it may become too late for effective control of large infestations. Beekeepers expressed this as a challenge which they faced in the 2021 fall. 

In addition to monitoring, CAPA has highlighted the importance of testing the continued efficacy of our leading varroa mite treatments. Here, ATTTA can help! This summer ATTTA is busy sampling hives across the Maritimes to measure the efficacy of both Apivar® and Api Life Var® in eliminating the mites within. This work will be completed in September and results shared with the industry shortly thereafter. 

The CAPA wintering losses survey provides us with valuable insight into the challenges and successes of the Canadian beekeeping industry. For more information on the results of the 2022 survey please read the full statement, found here. Thank you to all who participated!

Written by Annie Bennett, ATTTA Apiculturist, abennett@perennia.ca

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