Less than 100 years ago the first Varroa destructor mite was discovered in a hive of western honey bees. Between then and now, these mites have become so ubiquitous that we tell beekeepers to assume that every hive contains mites and that any "mite-free" hive will soon be infested with mites from another colony nearby. Varroa mites have proven time and again that they are very effective at spreading between colonies, and also across landscapes, and over national borders. It's far easier to list the places where this deadly parasite can't be found, instead of trying to list all of the countries that it has successfully invaded.
For the last few years, the standard story has been that the only places without varroa mites are the island of Newfoundland in Canada, the Isle of Man in the UK, and the entire continent of Australia. But now we may need to shorten that already short list of mite-free locations.
First detection of mites in Australia
In late June 2022, Australian officials announced the discovery of varroa mites at the Port of Newcastle in New South Wales, though mites were soon found in other hives hundreds of miles away. If just a few mites had been found in that one colony it would still have been cause for alarm. However, one person with knowledge of the government's response has disclosed that a commercial apiary near the original surveillance hive contained a horrifying 50 mites per 300 bees, indicating that the infestation may have been established for months, and could be much more widespread than initially hoped.
Australia taking steps to prevent the spread of varroa
The transportation of bee colonies in the state of New South Wales has been completely stopped by a government lockdown order, and colonies are being euthanized to try to contain the mites before they spread further. When an infested colony is found, all managed colonies within 10km (6.2 mi.) are being euthanized, and all colonies within 25km (15.5 mi.) are being inspected for mites, and destroyed if the mites are detected. At least 600 colonies have already been destroyed by the government. The 10km (6.2 mi.) radius covers the typical maximum foraging range of a colony, but bees have been known to fly further under some circumstances. Hopefully, the beekeepers whose hives have been destroyed will be compensated, though in many other countries invaded by varroa panicked government officials have adopted a "destroy the hives now, consider paying the beekeepers later" attitude.
These efforts are meant to protect Australia's bees from both varroa and varroa-transmitted viruses. It's also meant to protect the many Australian crops that depend on honey bees for pollination. Australian beekeepers will struggle if the mite spreads across the country, wiping out feral colonies and severely impacting the health of all managed bee colonies. Thankfully, Aussies will benefit from the decades of mite research and miticide development that has taken place throughout the rest of the world. Still, Australian beekeepers have thoroughly enjoyed their mite-free status, and most are willing to make serious sacrifices to try to maintain it.
Mites have been detected and eradicated in Australia before
This is not the first time varroa mites have been detected in Australia. For years, vigilant biosecurity officers in northern Australia have investigated (and exterminated) wild colonies of the Asian honey bee species Apis cerana (the original host of the varroa mite). In June of 2018, the Australian government also detected and eliminated a colony of varroa-infested honey bees on a ship coming from the United States. The bees were suspected to have swarmed into a crate in Texas, and then remained unnoticed as the ship traveled to the land down under. In all of these cases, the mites and bees were detected early, and swift and decisive action prevented the mites from becoming established. It remains to be seen whether the government will be able to effectively tackle this much larger mite problem before the mites move into feral colonies or are spread to a different state by a rogue beekeeper, or by some other means.
Newfoundland continues to evade varroa
If varroa mites become permanently established in Australia, the largest remaining varroa-free territory will be the Canadian province of Newfoundland and Labrador. The honey bees on the island of Newfoundland (and the isolated mainland portion of the province, Labrador) have never been infested by varroa mites, but the beekeepers and provincial agriculture officials know they must maintain constant vigilance.
Betterbee's Director of Research and Education, Dr. Peck, collaborated with Peter Armitage and Dr. Stephen Walsh from the Newfoundland and Labrador Beekeeping Association to draft a "Varroa Action Plan". The plan is meant to help the province monitor for mite incursions, educate beekeepers and the public on the importance of keeping the mites out, and consider different containment measures to try to eliminate the mites if they do arrive.
Though the plan has not yet been formally adopted by the provincial government, it represents a strong effort to keep Newfoundland from becoming the next region to fall to the mites' onslaught. The heart of the plan is very similar to the approach that Australia has taken: educate the public about the danger of importing bees; set up a plan to monitor "sentinel hives" to see if mites are detected in them; if mites are found, immediately assess the degree of the infestation by surveying other hives; and then consider euthanasia of all colonies within a certain radius to wipe out the mites before they spread to the rest of the bee population. Similar plans were attempted in other previously mite-free regions (such as New Zealand, Hawaii, and the continental U.S.) but obviously none of these plans stopped the mites.
Will Australians manage to eradicate varroa mites?
By euthanizing all colonies in a wide radius around the infection zone, are the Australian authorities keeping other bees safe, or will they eventually give up when they find that the mites are already widespread? This remains to be seen. The main lesson from many past varroa mite invasions is that humans often do too little too late, and the mites are often widespread and well established by the time they are first detected.
Eradication efforts began in New Zealand after the mites were first detected, but the government simply abandoned the process when they decided that the fight was hopeless (after many beekeepers had already had their hives destroyed). Swift, decisive action like the mass extermination of infested (or possibly infested) hives may be the only way for the government to succeed, but the dead bees and anguished beekeepers left in their wake have paid a high cost whether the mites are exterminated or not. If Australia manages to purge the mites from their island, they will be the first major landmass to do so successfully. However, if they fail, they will simply have to join a global community of beekeepers that have had to learn to live with varroa mites.
If you would like to learn how to live with varroa mites, make sure to take Betterbee's online class, Focus on: Varroa Destructor.
