An Introduction to Honey Bee Pests and Diseases in Ontario

Like all other insects, honey bees (Apis mellifera) are susceptible to pests and diseases, the majority of which are specific to honey bees. These can impact the health of a honey bee colony with effects ranging from minor stress to the death of the colony. Some of these pests and diseases are quite common while others are rarely encountered. It is important for beekeepers to be aware, learn to identify them and effectively manage pests and diseases to maintain healthy colonies. This is particularly important because the health of one beekeeper's colony can impact another beekeeper's colony in the surrounding area. (See below for listing of honey bee pests and diseases in Ontario.)

varroa mitesAmerican foulbroodhoney bee on flowersmall hive beetlehoney bee infected with deformed wing virus

Images (from left to right): Varroa mites, American foulbrood, honey bee, small hive beetle, honey bee infected with deformed wing virus.


Beekeepers in Ontario have access to a variety of educational and training resources in apiculture management, with many focussing on pests and diseases. Beekeepers are encouraged to use these resources and adopt an integrated pest management (IPM) approach to managing the long term health of their honey bee colonies.

Apiculture Program, Ontario Ministry of Agriculture, Food and Rural Affairs (OMAFRA)

This program addresses honey bee health issues in Ontario. The provincial apiarist tracks the health of the industry and directs apiary inspectors responsible for inspecting apiaries and monitoring for pests and diseases throughout the province under the Bees Act of Ontario. Before sell honey bees or used beekeeping equipment they are required to have honey bee colonies and/or equipment inspected to validate the health of the material and must receive a permit. This is also required for imports or exports of bees between jurisdictions. The Apiculture Program provides advisory and outreach regarding bee health.

For a list of local apiary inspectors see:

Ontario Beekeepers' Association (OBA)

This organization represents the beekeeping industry in Ontario. It is the largest group of commercial and non-commercial beekeepers in Ontario. The organization provides a variety of programs (research, marketing, etc.) and services to members and non-members. Access the OBA's website at

Technology Transfer Program, Ontario Beekeepers Association

This program works directly with beekeepers providing extension, applied research on regional pest management and disease control. A regular series of practical, intensive workshops on introductory beekeeping, integrated pest management and queen production are hosted in various parts of the province from spring to summer. These workshops are highly recommended to beginning and experienced beekeepers alike. The Technology Transfer program gives regular updates on research developments and current best management practices. Access the program on-line at; email: or telephone 519-836-3609.

Local Beekeeping Associations

There are currently 25 regional beekeeping associations across Ontario. These associations provide beekeepers with local information on beekeeping conditions and issues. Associations usually hold monthly meetings with guest speakers and discussion forums. The OBA provides a list of local beekeeping associations at the following link:

Townsend Laboratory for Honey Bee Research (University of Guelph)

This laboratory conducts apiculture research in Ontario, addressing issues of honey bee health and pathology with a focus on genetics, biology of honey bee parasites, immunity and behavioural ecology of honey bees. This lab produces scientific research on the fundamentals of apiculture, offers University courses in the field of apiculture and seminars at beekeeper meetings and conferences. A workshop is hosted by the lab every year. For more information visit their webpage at

Wildlife Damage

Assistance with wildlife damage is available to beekeepers in Ontario.

Table 1. Pests and Diseases of Honey Bees in Ontario


Deformed wing virus

Israeli acute paralysis virus

Kashmir bee virus

Black Queen cell virus


Many honey bee viruses are widely distributed.

The presences and levels of particular viruses may vary.

moderate to severe

Although there are no registered treatments specific to viruses, beekeepers may manage virus levels to a certain extent by managing varroa infestations.


treatment recommendations


American foulbrood

European foulbrood

widely distributed, less common

widely dististributed, less common

highly virulent and contagious


Prevent with antibiotics, inspection, quarantine and destruction of infected equipment.

Manage with antibiotics.

inspection program

treatment recommendations




Nosema apis

Nosema cearanae

widely distributed, common

widely distributed, common

widely distributed, common

usually a minor pest, rarely serious

may be virulent in winter

moderate to virulent

Manage by requeening.

Manage with antibiotics.


treatment recommendations

Parasitic Mites

Trachial mites

Varroa mites

Varroa mites resistant to fluvalinate and coumaphos

current distribution unknown

widely distributed, common in most regions

widely distributed, varies by region

moderate to serious

highly virulent, if not managed will kill colony

decreases the options for control

Manage with registered chemical treatments and tolerant bee stock.

Manage with registered chemical treatments and cultural practices.

Treatment options, sampling and monitoring for resistance.


treatment recommendations

Ontario breeding stock

Insect Pests

Wax moth

Small hive beetle

widely distributed

restricted distribution, presently known sites under quarantine

pest of week colonies and equipment

pest of weak colonies and honey stores, may have implications for exporting bees to other regions

colony management, best management of equipment storage

inspection and permits to prevent spread of pest, colony management, best management practices in the honey extraction facility


inspection program

treatment recommendations

Predators (insects and mammals)

fliles, hornets and wasps, mantids, spiders

mice, shrews




widely distributed

widely distributed

widely distributed

widely distributed

more common in northern and forested regions

minimal inpact


Racoons, skunks and bears may cause severe damage

limited control, location of beeyards

seasonal management

best management practices

best management practices

best management practices

workshops cover all predators

best management practices

Wildlife Damage Program covers racoons, skunks and bears

Recommended Reading and Additional Resources


Guzman-Novoa E., Eccles L., Calvete Y., McGowan J., Kelly P. and Correa-Benitez A. 2010. Varroa destructor is the main culprit for death and reduced populations of overwintered honey bees in Ontario, Canada. Apidologie. 4 (4) 443-451.


Paul Kozak
Provincial Apiarist
Ontario Ministry of Agriculture, Food and Rural Affairs
Animal Health and Welfare Branch
Tel: 519 826-3595 or 1-888-466-2372 Ext. 63595
Fax: 519 826-3233

For more information:
Toll Free: 1-877-424-1300