Between June 2024 and January 2025, American beekeepers witnessed helplessly to a tragedy: 62% of all the colonies of bees raised for commercial purposes died, beating a record that dated back … well, in the previous winter, when 55% of the colonies died.
In short, it is a black period for honey bees in the United States, but the bureaucratic delays and the cuts in search of the current American administration have slowed down the search for the causes of the last death. Today they have finally been revealed, in a study (for now still at the Preprint stadium, therefore waiting for Peer Review) published on BIORXIV That points the finger on mites, and their pesticide resistance.
Invincible mites. As mentioned, it took six months, from January to today, to complete the checks and identify the causes of the death of honey bees that devastated the American colonies last winter. The study was produced by the Usa, the US Department of Agriculture, which, however, has not yet publicly commented on the unquestionably worrying results: the vast majority of the dead colonies were positive for a series of viruses transported by bees’s mites, in particular those of the species Varroa Destructor.
Pesticides resistant. Not only that: the USDA also tested the guilty mites, and discovered that they were all resistant to a pesticide called Amitraz, which is the only specific for mites (more precisely therefore it is a acaricide). It is also a substance that can also cause damage to the colonies of bees and human beings, if used in large quantities – and it is here that the rip -off of immunity is.
Until the eighties, we had at least five different acaricide substances available; Over time, these parasites have developed total immunity to four of these five, and also the fifth, the amitraz, it is quickly losing its effectiveness.
Too little and too late? This means that if you want to have a hope of defeating an infestation of mites with amitraz, it is necessary to use potentially harmful quantities also for the colonies of bees. On the other hand, it is impossible not to take precautions against parasites: mites of the genre Varroa They are so devastating for beekeepers that you have been trying to select API with an innate resistance to mites for years. It is therefore not surprising that the Morìa of 2025 was caused by these small arachnids.
It is not surprising, but helps: now beekeepers know those who have to defend themselves, even if the fact that the USDA has put six months to publish its relationship could mean that for many companies it is now too late; The window to repopulate the colonies, in fact, closes with the end of summer, and since the study came out in early July it means that the beekeepers worse have only a couple of months to prepare for the next season.
