EXPERT REACTION: Honey bee parasite Varroa mites detected in NSW

It really has only been a matter of time before the Varroa mite established in Australia. Without early detection, it’s nearly impossible to prevent Varroa from spreading to feral honey bees and the rest of Australia. New Zealand has just had a very similar experience, including similar biosecurity protocols, but had better success for a time thanks to geographic barriers.

However, even if this incursion is snuffed out, the global nature of trade will continually bring infested honey bees to Australia – which happens relatively frequently from hives that happen to establish on ships or in shipping containers.

From the New Zealand experience, it will become harder to maintain hives, particularly for hobbyists, but the industry will eventually adapt to using miticides to prevent Varroa from killing hives. It’s not all doom and gloom though. It is important to note that honey bees are not Australian, and feral colonies use large amounts of the same pollen and nectar that declining native populations of bees and birds require. They also routinely use marsupial and bird nest boxes and hollows for their hives. In summary, Varroa will make life more complicated for beekeepers and agriculture, but may make things easier for our wildlife.

The recent Varroa mite incursion is concerning news for Australian agriculture. The devastating consequences for European honey bees and honey bee keepers are well discussed.

It is important to note that the Varroa mite will not directly impact Australian native bees as the mite's lifecycle is tightly linked to European and Asian honey bees (Apis mellifera and Apis cerana) only.

There is some potential for the Varroa mite to indirectly negatively impact native bees via virus spillover from mite-affected honey bees, although this is poorly understood and the impact is probably relatively low. Now more than ever, Australian native bees are a vital asset to Australian agriculture.

It is possible that this incursion will be eradicated, but it is a near certainty that Australia will not remain Varroa free in the future.

This is not the end of the world – as the rest of the world has been dealing with this issue for decades.

In addition, much of the natural environment may benefit from the incursion, as the mite will likely decimate the feral colonies of honey bees, which are at extreme densities and compete with managed hives for nectar and pollen, and  with Australian native animals for nectar, pollen and nesting hollows.

We are working to design selective insecticides that would hit Varroa but not harm honeybees. In this way, we are hoping to establish a more robust control strategy for when the time comes that Varroa slips through our defences (which have held up pretty well so far…). Most insecticides are non-selective – they will kill many insects, not just the ones you’re trying to target – so we are on a quest to change that.

The Varroa mite, a major parasite of honey bees, was recently discovered in biosecurity surveillance hives at the Port of Newcastle.

Varroa mites affect every other major beekeeping industry in the world, except Australia. The discovery has sent NSW into a bee lockdown – with no honey bees or beekeeping equipment being allowed to be moved across the state with hefty penalties for breaches – as authorities aim to eliminate the parasite.

But what threat does the mite pose to Australia? 

The research shows that if the Varroa mite establishes here it could cost Australia’s honey bee industry more than $70 million a year and have major impacts on supply of pollination services for horticultural industries worth $14.2 billion annually.

Having turned up next to the Port of Newcastle, the mites have most likely hitchhiked a ride with a feral bee colony on a container ship, and the mites are being analysed to work out what country they have come from and what viruses they may be carrying. 

These mites can’t reproduce on, or directly harm, our native bees, but the viruses the mites may be carrying could have the potential for spillover. 

Beekeepers and horticulturalists across the country depending on honey bees are certainly keeping a close eye on the situation as updates are provided by the Australian Honey Bee Industry Council and NSW DPI who are onto it with surveillance efforts to contain the outbreak.

Despite the grim outlook, I think all is not lost yet, if we act swift and hard.

I have my doubts though that the current zones (i.e. a 10 km eradication zone, 25 km surveillance zone and a 50 km buffer zone) installed by the authorities reach far enough.

As a precautionary measure, I would immediately prohibit any movement of beehives at least within QLD, NSW and VIC, because it just takes a single breach of the current exclusion zones in combination with beehives being transported across Australia for pollination services and we will soon end up with an uncontrollable spread of the varroa mites.

I am aware that such hard measures will cause a significant economical hit to the bee industry, but that would only be for a limited time period. In contrast, the associated economic impact would pale in comparison to the many millions of dollars it will cost the Australian bee-industry annually once the mites have become endemic, because then there will be no going back.