Thank you very much for the invitation to speak to you today. I was invited to speak about about honeybee mortality.
I'm not going to repeat much of how important bees are for agricultural and ecology, only to say that they play a critical role in the production of food and in sustaining ecosystems and biodiversity.
One-third of the food consumed in western societies is thanks to the contribution of the pollination services by bees. The annual value of honeybee pollination in Canada is estimated to be about $1.5 billion, and it exceeds $120 billion globally. The role of honeybees as pollinators is central to life support systems on the planet and, of course, in Canada.
That's why it is worrisome that we have been experiencing high rates of honeybee mortality. I have to say that this is a global issue, mainly in developed countries of the northern hemisphere. It's not only a Canadian issue, but also happens in some European countries and the U.S.
Between 2007 and 2022, we have lost about one-third of honeybee colonies each year, which has strong economic and ecological implications.
In Canada in particular we lost a record number of colonies during the winter of 2021-22. Particularly in some provinces, the national winter loss rate was 45.5%, which is three times higher than the suggested loss threshold and the highest we have had since 2007.
As for the causes of these high mortality rates, most scientists agree on the culprits, but there is some debate as to which of the culprits have more weight. When you analyze the information published in scientific journals about these losses, the frequent suspects are, number one, varroa mites and viruses transmitted by the mite; pesticides; deficient hive management; queen failures; stress caused by transportation or malnutrition, and adverse climatic effects.
In Canada, it seems that varroa mite populations grew more during the 2021 season than in average years. Late mite fall treatments is a commonly cited cause of poor varroa mite control. Also, comments have been made about ineffective control achieved with amitraz—which is one of the parasite chemical products that we use to control the mites, sold as Apivar strips—but to the best of our knowledge we don't have concrete evidence of mite resistance to amitraz so far in Canada.
I have some recommendations to address the problem. It is important to establish multisectoral and interdisciplinary approaches to better understand the causes of winter mortality and to reduce the rate of colony losses. Therefore, the collaboration between beekeepers, scientists and the government is important.
Beekeepers should follow best management practices to keep their bees alive, which include monitoring for mite levels and timely mite control—not just when we can, but timely mite control is important—as well as good fall management.
Scientists and tech transfer technicians should focus on studying more of the impact of the culprits of mortality and develop new strategies to mitigate colony mortality, which may include new formulations of acaricides, novel management practices, efficient methods to produce nucleus colonies and to overwinter queen bees.
Nutrition is important to develop protein supplements that improve honeybee health and colony growth. Additionally, many of our beekeepers are hobbyists and need training and education. Therefore, extension activities at the national level are needed.
In this regard, CAPA researchers are working on new formulations like essential oils and oxalic acid, as well as on breeding programs to develop bees that are more resistant to the varroa mite.
CAPA is assisting the Canadian Honey Council to facilitate the registration of an additional oxalic acid formulation with the PMRA for controlling varroa mites. Also, it is important to test acaricide efficacy. We have done that here in Ontario and have found no evidence of mite resistance to amitraz or flumethrin, but that has to be done in every province.
The tech transfer team committees in CAPA are establishing collaborations between tech transfer teams—