As the 2026 beekeeping season approaches, Canadian beekeepers are continuing to learn what Varroa mite treatment products and applications are approved for use in Canada. So far, this past fall and winter, the Pest Management Regulatory Agency (PMRA) has approved of Apivar 2.0®, Amiflex®, and VarroxSan^TM which will provide beekeepers with a few new options to select from in the near future. Adding to the list, the PMRA has recently approved of a new application method for oxalic acid, which is the use of glycerin strips. To learn more about the glycerin strip method, and how this may benefit beekeepers to manage Varroa mites, read this week’s blog.

New Application of Oxalic Acid: The Glycerin Strip Method

Previously, in Canada, the only approved application methods for oxalic acid were the solution method, also known as the dribble method, and the use of vaporizers. Beekeepers can continue using either of the mentioned methods, but now there is a third option available known as the glycerin strip method. It is important that beekeepers understand that all three methods deliver the same product and have the same active ingredient, however, beekeepers can select the application method that works best within their operation.

Oxalic acid dihydrate

The glycerin strip method requires some effort and work to prepare the product for application. Beekeepers must be willing to devote the time to properly preparing the product if choosing this method. According to the label instructions, the product should be prepared with 99.7% food-grade vegetable glycerin and oxalic acid dihydrate at a 1:1 ratio. The solution should slowly be heated until the oxalic acid dissolves within the glycerin and the solution becomes transparent. When heating the solution the temperature should remain between 45°C and 70°C. Then beekeepers can saturate absorbent strips (e.g. cellulose or other natural fibres) and place them in an open container. Strips should be used within one month of preparation.

Each hive should be treated with 40g of oxalic acid. In order to determine how many strips are required to achieve 40g, beekeepers must weight a strip before it is saturated with solution, and again once it is saturated, and determine how much solution has been absorbed. For example, if one strip absorbs 20g of solution, then half of that would be oxalic acid (10g) and, therefore, 4 strips would be needed to achieve the 40g dosage. Beekeepers can trim strips to achieve the required dosage. Strips can be placed on the top bars of frames or allowed to hang down between frames. Strips must remain in the hive for 42 days.

A main advantage to using this application method is that treatment can occur with honey super on hives, which differs from application using a vaporizer or the dribble method. Another advantage to this treatment method is that oxalic acid is relatively inexpensive, and both the dribble method and glycerin strips do not require an expensive applicator (i.e. vaporizer).

There are a couple of disadvantages to preparing these chemical strips at home compared to purchasing a commercially prepared product. In addition to the time and effort required to prepare the strips, there are also associated risks if the product is not prepared safely and correctly. To start, beekeepers must be diligent when measuring the vegetable glycerin and oxalic acid to get a precise 1:1 ratio, and they must weigh each strip to ensure the correct dosage will be administered to each hive. Providing too much or too little of the active ingredient can be harmful to the bees, will impact the efficacy of treatment and potentially contribute to future reduced efficacy. Furthermore, when heating the solution, it must remain between 45°C and 70°C. Underheating the solution will prevent oxalic acid crystals from dissolving, and overheating the solution will degrade the oxalic acid, both of which will reduce the efficacy of the treatment.

Another thing to be mindful of when preparing these strips at home is your own safety. Oxalic acid dihydrate is a hazardous chemical that can cause acute dermal toxicity and has the potential to cause serious eye damage and/or irritation. Oxalic acid dihydrate has multiple health hazards if the chemical is inhaled or ingested. Therefore, proper personal protective equipment (e.g. gloves, protective eyewear, and a properly fitting organic acid respirator) should be worn while preparing the solution. Ideally, the solution should either be prepared in a fume hood or a well-ventilated area, and extra caution should be taken to prevent contamination of any area, or equipment, food is prepared or consumed in.

It is important to recognize that this treatment does not target mites under capped brood cells. Therefore, the best time for beekeepers to use this treatment is when there is a low amount of brood present (e.g. after a queenless split, early season, or late season).

As with all Varroa mite products and application methods, it is essential that beekeepers follow the precise instructions provided by the PMRA regarding dosage, treatment period, frequency of application and application methodology. Not following the instructions can be harmful to bees, impact the efficacy of treatment and could contribute to future reduced efficacy of products. If you have questions regarding oxalic acid glycerin strips, or other Varroa mite products and applications,  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

Over the past few months a couple of Varroa mite treatments have been registered for use in Canada, including VarroxSan^TM and Apivar 2.0®. Adding to that list, the Canadian Pest Management Regulatory Agency (PMRA) has recently registered Amiflex®, which is a gel formulated product containing the active ingredient amitraz (1.99%). Read this week’s blog to understand how Amiflex® may be incorporated into Canadian beekeepers’ Varroa mite management plans.

What Beekeepers Should Know about Amiflex®

Amiflex® is a Varroa mite treatment containing the active ingredient amitraz (1.99%) and is administered to colonies as a gel. The product, manufactured by Véto-pharma, has recently been registered for use in Canada by the Pest Management Regulatory Agency (PMRA). As part of an integrated pest management approach to controlling Varroa mites, beekeepers need to use a variety of chemical treatments and reduce reliance on a singular product. Having multiple treatment options available makes it easier for beekeepers to work different products into their IPM plan.

Amiflex® can be used to treat phoretic mites whether or not brood is present in the colony, but the product does not target mites under capped brood cells. Additionally the product is not temperature-dependent and can be used throughout the beekeeping season.

To apply Amiflex®, beekeepers must ensure that honey supers are removed, as the product cannot be administered while honey supers are present. Then beekeepers should scrape frames clear of all excess wax and propolis that could prevent the bees from coming in contact with the gel. In particular, top bars, top feeders, and the bottom of the frames in the top brood box should be well scraped. Next, beekeepers can load and secure the Amiflex® syringe into the dosing gun following manufacturer instructions. Using the dosing gun, an application of 2 doses of 3mL per brood box should be applied to the included tongue depressors, which are placed on the top bars of two different frames. Beekeepers should leave a minimum of one frame between the two frames with gel. The product should be applied to frames in the centre of the brood nest. For a double colony the total application should be 4 doses of 3mL (12mL) (2 frames in each brood box).

Beekeeper applying Amiflex® treatment to honey bee colony ©Thierry Vincent (Véto-pharma).

The treatment period of Amiflex® is 7 days. After 7 days any leftover treatment should be removed, and honey supers are allowed to be placed on colonies.

According to the manufacturer, Amiflex® is different from other amitraz products as it has a relatively quick action. Additionally, according to the PMRA label, the product can be used two times a year, either as two applications 14 days apart, or as two separate applications (7 days each) at different times during the year. If a colony or yard has high Varroa mite levels, it is recommended to apply the second application of Amiflex® 14 days after the first application to target emerging bees and phoretic mites.

Beekeepers must remember that Amiflex®, just like any other Varroa mite treatment, should only be applied when monitoring indicates mite levels are at or exceeding the economic threshold. Beekeeper should monitor following treatment to understand if the treatment was effective. Additionally, it is important that beekeepers understand that Amiflex® does not provide a new active ingredient to the Canadian beekeeping industry, but rather a new application of an already registered active ingredient – amitraz. So, if beekeepers want to use an amitraz-based product as part of their IPM plan, it is recommended that they select one of the available delivery methods (strips or gel) and alternate this treatment with another product that contains a different active ingredient.

The registration of Amiflex® will hopefully provide the Canadian beekeeping industry with another Varroa mite treatment option. Beekeepers can anticipate that the product will be available to purchase in the near future, but the exact date this product will be available in beekeeping stores is still unknown. For any questions regarding Varroa mite treatment and management, reach out to the ATTTA team.

References

Pest Management Regulatory Agency. https://pr-rp.hc-sc.gc.ca/1_1/view_label?p_ukid=402262946

Véto-pharma. https://www.veto-pharma.com/beekeeping-products/amiflex-amitraz-flash-treatment/

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

Protecting pollinators from pesticides is crucial to a successful and prosperous pollination industry. Agrochemical use is necessary in modern cropping systems and required to maintain honey bee health. Understanding more about the correct use of these compounds and how to mitigate risks for pollinators is important for both beekeepers and fruit producers. This week we will look at one example product to gain further insight into label and product information to help understand associated risks and the precautions you should take.

What You Need to Know About Agrochemical Product Information

Health Canada’s Pest Management Regulatory Agency is responsible for pesticide regulation. Pesticides are stringently regulated in Canada to ensure they pose minimal risk to human health and the environment.

Manufactures are required to provide information on various aspects of their product. We will use Merivon^®, a common fungicide for blueberry crops, as an example of the types of information a manufacturer must provide. This product may be used during blueberry bloom and therefore has potential considerations for honey bees and other pollinating insects.

Pesticides must be registered for specific crops and uses. Merivon is registered for use on blueberry crops to control Anthracnose, gray mold, Phomopsis Twig Blight, and Septoria Leaf Spot. All products will receive a registration number, with our example Merivon, having the registered number of 33951.  They will have a product name (Merivon Fungicide), and a registrant name (BASF CANADA INC.). The manufacturer must provide all information on all active ingredients. For Merivon the active ingredients are Pyrcolstrobin and Fluxapyroxad.

 

Merivon Fungicide BASF©

Manufacturers must also provide a Safety Data Sheet (SDS) for their product. The SDS has numerous requirements, including hazard identification for human health and the environment. Merivon is classified as acute oral toxicity, acute inhalation toxicity, skin corrosion/irritation, reproductive toxicity, specific organ toxicity, and hazardous to the aquatic environment. The SDS includes information on First-Aid measures, fire fighting measures, accidental release measures, handling and storage, personal protection measures, physical and chemical properties, stability and reactivity, ecological information, disposal information, transport information, and regulatory information. Anyone using this product should familiarize themselves with the label instructions and the SDS.

The SDS also provides information on toxicology. The toxicological information provides specific values about the degree of toxicity for different routes of exposure. For example, the LD₅₀ of Merivon for oral exposure to a female rat ranges between 50 and 300 mg/kg. For context, the LD₅₀ of Arsenic for oral exposure to a rat is 763 mg/kg, which means it is relatively less toxic than Merivon in this comparison. The LD₅₀ of Merivon for dermal exposure to a female rat is greater than 5000 mg/kg. The LC₅₀ of Merivon for inhalation exposure to a female rat is 2.81 mg/L. The LD₅₀ is calculated per kilogram of body weight and meant to only indicate comparable toxicity to other animals.

By way of further explanation, the median lethal dose (LD₅₀) is the amount of a substance that kills 50% of the test population, usually modelled using rats. The lethal concentration (LC₅₀) is the concentration of a chemical that kills 50% of the test population. These terms are often used interchangeably, but the LD is the lethal amount (or dose) of a solid substance, and the LC is the lethal concentration of a liquid substance. It is also important to understand that these measurements are time dependent. An LD₅₀ or LC₅₀ is determined within a certain time period (typically 4 hours since exposure). The LD₅₀ or LC₅₀ also differ depending on the method of exposure, whether it be topical, oral or inhalation exposure to the chemical. The values are determined through lab-based experiments, where a specific sample size is required for the experiment to have statistical significance.

According to use recommendations, Merivon has low toxicity to bees. Under a shared framework supported by PMRA, the US Environmental Protection Agency states that if the LD₅₀ of the pesticide is greater than 11 micrograms per bee it is relatively nontoxic, and no bee caution statement is required on the label. Generally, fungicides are not considered to have toxic effects on bees but ongoing research suggests there is still uncertainty as to the real-world consequences of exposure to these pesticides (Rondeau and Raine, 2022).

When using pesticides there is a lot of important information on the labels that must be understood and followed so that the treatment is effective, but also so no harm is done to plants and animals, and their environment. In Canada, it is an offence under the Pest Control Products Act to use any product in a way that is inconsistent with the directions on the label.  Pesticides can pose a threat to honey bees and other pollinators. Therefore, all precautions and directions on pesticide labels must be followed to avoid impacts of pesticides to bees.

We are excited to announce that more information about protecting pollinators from pesticides with be available soon! To be published: “PRACTICES TO PROTECT POLLINATORS FROM PESTICIDES – WILD BLUEBERRY”.

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 abyers@perennia.ca

References

Rondeau, S. and Raine, N.E., (2022) Fungicides and bees: a review of exposure and risk. Environment International, 165, p.107311.

Note: Any named product mentioned in this article is not an intended endorsement or discrimination of that product.  Specific examples are used for information and explanation purposes only.  Further information on these products is available through the manufacturer.