Apivar® 2.0: An update for U.S. beekeepers
Over the past several weeks, we have received reports from U.S. beekeepers describing unexpected and, in some cases, serious problems after treating colonies with Apivar® 2.0. These reports include significant losses of adult bees and, in some cases, colonies that appeared to abscond.
As your bees always come first, we want to address these reports openly and directly.
At the same time, it is important to put these reports into context. The experiences reported to us represent a limited number of cases compared with the number of colonies treated with Apivar® 2.0 since its launch in May 2025. Nevertheless, every report of an unexpected effect matters to us. We are taking each case seriously and investigating them thoroughly to identify any common factors that may help explain what is being observed.
Apivar® 2.0 is a genuinely different formulation from the original Apivar®, with a different strip size and a different amitraz release profile. It was developed in response to feedback from beekeepers looking for improved treatment performance and ease of use. Compared with the original formulation, Apivar® 2.0 releases amitraz faster, resulting in greater mite drop during the early weeks of treatment. Apivar® 2.0 went through many years of laboratory, controlled and field trials in North America, New Zealand and Europe, under a wide range of climates and beekeeping conditions. Apivar® 2.0 was not developed through trial and error in commercial hives. Effects of the type currently being reported were not observed during those trials. At the same time, no development program can reproduce every possible combination of conditions that a product may encounter once used across thousands of colonies and different beekeeping environments. Commercial use can reveal interactions between environmental conditions, hive configuration, colony characteristics and application practices that may not have been identified during development.
What we know today
Since the beginning of our investigations, we have found no evidence to date of a manufacturing defect or batch quality issue.
We are reviewing the individual cases reported to us, including the product batches involved, treatment conditions and colony management, while looking for common factors that could help explain what is being observed.
Several of the cases reported to us occurred under hot and humid conditions. In our observations so far, colonies with good ventilation, without entrance reducers, and with less direct exposure to the sun have shown fewer of the effects reported in other cases.
However, these are observations, not conclusions about causality. We do not yet know whether temperature, humidity, ventilation, application practices, colony characteristics or a combination of these factors may contribute to the reported effects.
We are therefore continuing to investigate these factors and are working with independent researchers and experienced beekeepers on comparative field observations under different conditions.
Our objective is not to draw conclusions prematurely. It is to understand what is happening in the field and to identify, based on evidence, the conditions under which these unexpected effects may occur.
Véto-pharma, October 2, 2026
What beekeepers can do now
If you are using Apivar® 2.0 for the first time, consider testing it on a small number of colonies under your local conditions before treating a larger number of colonies.
Watch colonies closely, especially in the first hours and days after treatment.
In some reported cases, the connected double strips were not separated, resulting in twice the recommended dose being applied.
Use one strip per five frames covered with bees, as stated on the label.
Where possible, maintain good hive ventilation, particularly under hot and humid conditions Based on current observations, colonies without entrance reducers appear to have been less affected.
These precautions are intended to help beekeepers manage the current uncertainty while our investigation continues. They do not replace the approved product label.
Please tell us what you see
If you have seen unexpected effects, please write to pv@vetopharma.com. Include your contact details, location of the apiary, treatment date, colony strength, mite levels, queen and brood status, weather, hive setup and ventilation, other treatments used, and photos or video if possible.
Detailed field information is extremely valuable to us. Every well-documented report helps us compare cases, identify common factors and move faster towards answers.
Our commitment
Our responsibility is not to dismiss these reports or to speculate about their cause without sufficient evidence. It is to listen, investigate the facts and share what we learn with the beekeeping community.
We believe that the right approach is to be transparent about what we know, clear about what we do not yet know, and rigorous in finding the answers.
Thank you to the beekeepers who have taken the time to report on their experiences and provide detailed information. Your feedback is an important part of this investigation.
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If you have questions not related to adverse effect reporting, or just want to reach out to us, please email info@vetopharma.com instead, and keep pv@vetopharma.com for reports.
Sincerely,
The Véto-pharma team