From Health Canada:
1.0 Bee Health
Over the past few years, there have been increasing reports of high overwintering losses and significant challenges in maintaining healthy bee colonies both in Canada and abroad. Bee health is a complex issue and is affected by many factors. According to Agriculture and Agri-food Canada, factors affecting the survival and health of honeybees include:
- Parasites, pests and pathogens: For example, Varroa mites, the parasite Nosema ceranae, and honeybee viruses impact bee health.
- Habitat loss and food supply: Bees restricted to foraging on crop monocultures may require supplementary feeding by beekeepers.
- Queen bee quality: Healthy, long-lived queens are important to maintaining vigorous, productive hives. Queen health can be compromised by factors such as inadequate selection and mating and exposure to pathogens and pesticides.
- Weather: Long, harsh winters or cool, long springs can result in higher levels of colony death.
- General hive management: Management techniques vary among beekeeping operations and can influence honeybee survival.
- Exposure to pesticides: Bees could be affected by unintentional exposure to agricultural
- pesticides used to protect crops and by pesticides used in hives to protect bees from parasitic mites.
There is much more to this report. To access the full report follow this link.