Easy-to-Understand Guide on Using Apiguard for Varroa Mite Control in Beekeeping

Apiguard is an effective treatment against the Varroa mite, renowned as one of the most widely used natural pesticides. Its main ingredient is thymol, a natural compound derived from thyme, which has demonstrated clear laboratory efficacy against Varroa mites. One of Apiguard’s strongest points is its ease of use; it comes in a gel form that’s straightforward to apply in infected hives. According to the manufacturer and many beekeepers, Apiguard poses no risk to bee safety, and its impact on worker and queen bee activity is significantly less than other natural treatments.

Before using Apiguard, it’s true that it does not harm bee health, but this statement is relatively contextual, depending on the general health of the hive targeted for treatment. Even the gentlest medications require caution during use. Ensure your hive is in reasonably good health, as medications won’t help in the case of a hive that’s weak and on the verge of collapse. You should also ensure the hive has enough food, as bees naturally tend to overeat in situations of stress or perceived danger, which in this case is beneficial as the increased internal activity of the bees will help spread the thymol more effectively. For better results, you should also work on improving airflow in the hive, for example, by adding an empty box on top, especially on hot days since thymol evaporates quickly in heat, and at high concentrations, it could harm the bees. Therefore, it’s advisable to also use mesh floors (openings that allow for air and debris flow, and mite drop) to maintain proper ventilation inside the hive.

The best time to apply Apiguard

Time is crucial for Apiguard success or failure, largely depending on the timing of its use. This treatment is most effective in warm weather, especially between 15°C and 40°C, because thymol needs this temperature range to evaporate moderately and effectively. Usually, this temperature is available during summer or autumn, which is strategic because it does not coincide with nectar gathering periods, ensuring the treatment spreads more effectively due to increased internal bee activity.

Increased bee activity during non-nectar gathering times may seem contradictory to beginners but reflects a realistic truth. When bees are not busy collecting nectar, they are more committed to maintenance work, caring for larvae, managing hive ventilation and temperature, and engaging more in self-care and care for others, all activities that help spread treatments like Apiguard.

Avoid using Apiguard in extreme cold or intense heat

When temperatures drop below 15°C, its effectiveness significantly decreases. Also, avoid using it when temperatures exceed 40°C, as excessive heat accelerates the evaporation of thymol in a concentrated form. Generally, when temperatures exceed 25°C, use only half a dose (25 grams) spread over several weeks, with the possibility of adding a third dose if necessary.

Consider not only the temperature at the time of thymol application but also the average temperature throughout the treatment period. If you use thymol in the morning during summer and the temperature does not exceed twenty degrees, do not forget that it will certainly rise during noon and that this will recur throughout the treatment duration.

If you use Apiguard on a sunny moderate autumn day, followed by days of severe cold, it will likely lose its effectiveness.

Therefore, it’s essential to check the temperature levels throughout the entire treatment period. Moreover, you should continuously monitor Varroa activity after using Apiguard. While treatments generally require ongoing care and monitoring, Apiguard, in particular, demands greater vigilance, as its effectiveness is primarily temperature-dependent.

Be cautious about using Apiguard during spring

While it’s permissible to use Apiguard in spring, it’s better to avoid its use during this season if possible. Spring is a vital time for hive growth, with egg-laying by the queen being a particularly high priority. Unfortunately, thymol treatments like Apiguard may temporarily stop the queen from laying eggs. Would you want to halt egg-laying during this crucial building period?

What to avoid when using Apiguard

Avoid using Apiguard or any other pesticides, even natural ones, during the peak of nectar gathering and honey production periods, typically in spring or summer. It’s better for the bees to focus their efforts on producing honey rather than on cleaning themselves and their home from thymol. Honeycomb contamination with thymol is possible, and while this substance generally does not harm humans and is used in many therapeutic areas due to its antiseptic and antibacterial properties, contamination can alter the taste of honey.

Avoid treating weak colonies with Apiguard; consider merging them with a stronger one first. But think twice before merging if the weak hive is significantly infected, as you risk weakening the stronger hive. Ultimately, you might end up with a slightly larger but more Varroa-infected hive. Weigh the benefits and losses, and consider whether it’s truly possible to save the weak hive or if it’s doomed to collapse.

Always wear impermeable gloves (like nitrile gloves) when handling Apiguard sachets and avoid direct contact with brood when applying the treatment.

Important note: For detailed instructions and additional guidelines on using Apiguard, always refer to the treatment instructions as written on the product, and visit the Apiguard website.

Is Apiguard truly effective against Varroa?

The efficacy of Apiguard varies from one apiary to another, and from one hive to another. Some studies have shown that Apiguard had a limited effect on Varroa (Gregorc et al., 2012), while other studies reported a higher success rate, removing between 76% and 98% of Varroa. These results clearly illustrate the significant variability in efficacy.

In countries with warmer climates, like Italy, Algeria, and Mexico, some studies have shown that Apiguard was highly successful in combating Varroa (Domatskaya et al., 2021).

However, results may vary within the same apiary from year to year, fluctuating between years of high effectiveness and years of weak effectiveness.

It’s challenging to find a single logical explanation to understand the variability in effectiveness from one hive to another. We know temperature plays a role, but it may not be the only factor. Choosing the optimal treatment period or ‘treatment window’—the most effective time to apply the treatment based on factors like seasonal temperature changes, the current level of Varroa infestation, and the bees’ natural lifecycle—along with considering the level of Varroa infestation before treatment, and even the natural resistance of the bee strain, are all variables that might ultimately determine the overall result.

There is a consensus among beekeepers that Apiguard should be supplemented with another treatment, such as medications containing oxalic acid. When we say a complementary treatment, we mean a different treatment based on different active ingredients, like mixing a medication containing thymol with another containing formic acid or amitraz. This approach is particularly important because diversification prevents Varroa from developing immunity against these natural components.

Note: I am not affiliated with Apiguard or its manufacturer.

Sources

• Gregorc, A., & Planinc, I. (2012). Use of thymol formulations, amitraz, and oxalic acid for the control of the Varroa mite in honey bee (Apis mellifera carnica) colonies. Journal of Apicultural Science, 56(2), 61-67. https://doi.org/10.2478/v10289-012-0024-8
• Domatskaya, T.F., Domatsky, A.N., Levchenko, M.A. (2021). The effectiveness of Apiguard against varroatosis (the case of Tyumen region apiaries, Russia). Ukrainian Journal of Ecology, 11(9), 122-126. Licensed under a Creative Commons Attribution 4.0 International License.

Acknowledgments

• Special thanks to Joubrane Shadani and Khalil Shadani for their effort in reviewing and translating the references for this article.
• Featured image adapted from ‘The effectiveness of Apiguard against varroatosis’ study PDF, used under CC BY 4.0, with modifications by Joubrane. Original study by T.F. Domatskaya, A.N. Domatsky, M.A. Levchenko.