Over the past six months new commercially-made Varroa mite treatments have been registered for use in Canada, including VarroxSan^TM, Apivar 2.0®, and Amiflex®. The Maritime beekeeping industry has waited eagerly to learn the availability these products from local and national retailers. Read this week’s blog to learn which products are already on the shelves, and when we can expect to purchase each product locally and nationally.

Update on Newly Registered Varroa Mite Treatments in Canada

These past 6 months have brought options for Varroa mite management in Canada, as the Pesticides Regulatory Directorate (formerly PMRA) registered three new Varroa mite treatments: VarroxSan^TM, Apivar 2.0®, and Amiflex®. VarroxSan^TM, developed and manufactured by Vita Bee Health Canada Ltd., contains the active ingredient oxalic acid dihydrate (18.42%) and is administered using strips. Apivar 2.0®, manufactured by Véto-pharma, contains the active ingredient amitraz (3.00%) and is a contact acaracide delivered using plastic strips. Amiflex, also manufactured by Véto-pharma, contains the active ingredient amitraz (1.99%) and is administered to colonies as a gel. To learn more about each of these products, review the previous blog posts by ATTTA: “New Varroa Mite Treatment Product: VarroxSan^TM” published on November 13, 2025, “What Beekeeper's Should Know about Apivar 2.0®” published on November 27, 2025, and “What Beekeepers Should Know about Amiflex®” published on January 15, 2026.

The availability of each of these commercial products differs at both the local and national levels. To start, of the three products, currently, only VarroxSan^TM is being sold from Maritime beekeeping stores including Country Fields Beekeeping Supplies (Fall River, NS), Maritime Bee & Agriculture Supplies (Sussex, NB) and Buzzworks Beekeeping & Apiary Supplies (Moncton, NB). All three have VarroxSan^TM in stock in both 20-strip and 60-strip packs. Golden Greens Beekeeping Supplies (Onslow, NS) anticipates selling VarroxSan^TM in the near future. Currently, the local beekeeping stores do not have Apivar 2.0® or Amiflex® on their shelves. Apivar 2.0® is expected to be available locally either late 2026 or in spring 2027, but there is no definite availability date for the Maritime region yet. Amiflex®, although not currently on the shelves of these stores, could be purchased locally as Country Fields Beekeeping Supplies has the ability to bring in bulk orders if requested by commercial beekeepers.

Although not all three products are able to be purchased locally this season, beekeepers can shop outside the region. The national distributors, Bee Maid Bee Supplies and Dancing Bee Equipment, both have VarroxSan^TM, Apivar 2.0®, and Amiflex® available for purchase. These national stores have VarroxSan^TM in stock in both 20-strip and 60-strip packs. There is an expected shipment of VarroxSan^TM into Canada later this summer, which should provide a consistent supply of the product throughout the season. For any Maritime beekeepers eager to use Apivar 2.0® or Amiflex®, both are available to ship to the Maritimes this beekeeping season.

Left to right: VarroxSan^TM, Apivar 2.0® and Amiflex® (Dancing Bee Equipment)

The registration of VarroxSan^TM, Apivar 2.0®, and Amiflex® has provided the Canadian beekeeping industry with 3 new products, which can be incorporated within integrated pest management plans. In order to gain familiarity, ATTTA will be using all three new products this season and be able to answer beekeepers’ questions.  For any questions regarding Varroa mite treatment and management, reach out to the ATTTA team.

Connecting with ATTTA Specialists

If you’d like to connect with ATTTA specialists or learn more about our program, you can:

visit our website at https://www.perennia.ca/portfolio-items/honey-bees/

Email attta@perennia.ca

Understanding Vairimorpha Disease in Honey Bees

Honey bees depend on a healthy gut to digest food, absorb nutrients and maintain a strong immune system. When parasites invade this part of the digestive system, they can disrupt these processes and weaken the entire colony. One of the most common gut parasites found in honey bees is Vairimorpha (formerly Nosema), a microsporidian that infects honey bees and harms their colonies.

Understanding Vairimorpha in Honey Bees

Vairimorpha disease is caused by two spore-forming species, Vairimorpha ceranae and Vairimorpha apis. These parasites infect the epithelial cells of the honey bees’ ventriculus (midgut), where digestion and nutrient absorption take place ¹. As these cells become damaged, bees struggle to process food efficiently, which can shorten worker lifespan and weaken colony productivity ¹. Because the infection is internal, honey bees do not show outward symptoms specific to this disease, making this disease easy to overlook without testing. 

Figure 1: Vairimorpha spp. spore (arrow) under a compound microscope 100x

Even without obvious clinical signs, Vairimorpha infections can influence colony performance. Reduced nutrient absorption can weaken foraging ability, lower honey yield and slow spring build-up ¹. Classic symptoms such as fecal staining have been associated with V. apis ². The dominant species in Canada, V. ceranae, does not have distinct symptoms ². This makes visual inspection alone not reliable for detecting this disease and shows the importance of routine monitoring. 

The microsporidian spreads easily within a colony because the spores are environmentally resistant and spread through fecal-oral transmission. Bees can ingest the spores while cleaning contaminated comb, grooming or by trophallaxis ². Foragers can also pick up the spores from contaminated water sources ². Once inside the gut, the spores infect the midgut and multiply, allowing infection to spread quickly. Since this disease is transmitted through normal social behaviours, even strong colonies can become infected without showing obvious signs.

For decades, these pathogens were referred to as Nosema apis and Nosema ceranae. However, recent genomic work has shown both species are more closely related to the genus Vairimorpha, clustering with Vairimorpha necatrix, rather than the species Nosema bombycis in the genus Nosema ³. Although the scientific names have changed, the disease is still commonly referred to as Nosema or Nosemosis in the apiculture industry. It is important to note that this taxonomic update does not change how the disease is diagnosed or managed. 

Across Canada, research shows a clear shift toward V. ceranae being the dominant species. In a study on Nova Scotia colonies, all positive Vairimorpha samples contained V. ceranae, with V. apis not detected at all ⁴. Similar reports in other provinces, such as Ontario and Alberta, found that in polymerase chain reaction (PCR) surveys, V. ceranae was more common than V. apis ⁵.

Diagnosing Vairimorpha infections relies on microscopy, which allows beekeepers to quantify the spores. These spores represent the mature, environmentally resistant stage of the parasite, so spore counts provide an indirect measure of infection intensity. However, because the spores of V. ceranae and V. apis are difficult to distinguish, species-level identification requires polymerase chain reaction (PCR) to detect genetic differences between the microsporidia ².

Seasonal monitoring is essential because Vairimorpha levels fluctuate throughout the year. In Nova Scotia, McCallum et al. (2020) have shown that spore loads spike in May, then drop through the summer, with a smaller increase in spore loads in the fall ³. In Ontario, Emsen et al. (2020) have shown that infection intensity and prevalence of V. ceranae are highest in spring and summer seasons, and slightly lower in the fall ⁷. These seasonal trends emphasize the value of spring and fall testing for providing meaningful information on spore counts. 

Understanding the treatment of this disease is essential, like how fumagillin works and when it is most effective, when making management decisions. Next week’s blog will explore how Fumagillin interacts with the parasite inside the bee and how effective this is. 

 Written by Kaitlyn Newton, ATTTA Seasonal Apiculturist

Connecting with ATTTA Specialists

If you’d like to connect with ATTTA specialists or learn more about our program, you can:

visit our website at https://www.perennia.ca/portfolio-items/honey-bees/

Email attta@perennia.ca

References:

1. Sammataro, D. and Avitabile, A. 2021. A Beekeeper’s Handbook: Fifth Edition. Cornell University Press. 
2. Pernal, S.F. and Clay, H. 2013. Honey Bee Diseases & Pests, Third Edition. Canadian Association of Professional Apiculturists, Beaverlodge, AB, Canada, 68 pp. 
3. McCallum, R., Olmstead, S., Shaw, J. and Glasgow, K., 2020. Evaluating efficacy of Fumagilin-B® against nosemosis and tracking seasonal trends of Nosema spp. in Nova Scotia honey bee colonies. Journal of Apicultural Science, 64(2), pp.277-286.
4. Bojko, J., Becnel, J., Bessette, E., Edwards, S., Gao, J., Huang, W.F., Katanić, N., Khalaf, A., Li, T., Snow, J.W. and Solter, L.F., 2025. Nosema or Vairimorpha: genomic/proteomic support to a complex socio-economic issue rooted in taxonomic change. Journal of Invertebrate Pathology, 212, p.108376. 
5. McCallum, R., Olmstead, S., Shaw, J. and Glasgow, K., 2020. Evaluating efficacy of Fumagilin-B® against nosemosis and tracking seasonal trends of Nosema spp. in Nova Scotia honey bee colonies. Journal of Apicultural Science, 64(2), pp.277-286.
6. Emsen, B., Guzman-Novoa, E., Hamiduzzaman, M.M., Eccles, L., Lacey, B., Ruiz-Pérez, R.A. and Nasr, M., 2016. Higher prevalence and levels of Nosema ceranae than Nosema apis infections in Canadian honey bee colonies. Parasitology research, 115(1), pp.175-181.
7. Emsen, B., De la Mora, A., Lacey, B., Eccles, L., Kelly, P.G., Medina-Flores, C.A., Petukhova, T., Morfin, N. and Guzman-Novoa, E., 2020. Seasonality of Nosema ceranae infections and their relationship with honey bee populations, food stores, and survivorship in a North American region. Veterinary sciences, 7(3), p.131.