Eradicating varroa mites – the sweetest success

Welcome to Turf ‘n’ Surf, a podcast that tells stories in Queensland’s farming, fishing, biosecurity and forestry sectors.

Our honey producing bees are under attack from a tiny invasive parasite measuring less than two millimetres in length and width.

The varroa mite is an insidious pest that poses a significant biosecurity threat to the common European honeybees whose pollination services add an estimated $14.2 billion to the Australian agricultural and horticultural industries each year.

This episode of Turf’n’Surf, looks at the impact of varroa mites on the honey industry overseas, how Biosecurity Queensland is working to eradicate varroa mites detected in Townsville, and what the Queensland Government is doing to take the sting out of varroa mites.

You’ll hear from the Chair of the Australian Honey Bee Industry Council, Trevor Weatherhead; Manager of the Townsville-based National Varroa Mite Eradication Program, Rob Stephens; and Biosecurity Queensland’s Manager Plant Incident Response and Preparedness group, Rebecca Sappupo.

Find out how varroa mite detections in Queensland in 2016, 2019 and 2020 were met with a swift and effective response, delivering the sweetest of successes.

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TRANSCRIPT

Program intro: Welcome to Turf and Surf, powered by Queensland’s Department of Agriculture and Fisheries, shaping and protecting food and fibre for tomorrow’s Queensland.

Host: Casual reviewers of 1970s pop culture could easily be forgiven for thinking that human beings were under imminent threat from swarms of killer bees.

Cheesy ‘B’ grade movies like “The Savage Bees”, “Killer Bees” and “The Swarm” fuelled a panicked buzz that rampant swarms of mutant killer bees were poised to deliver lethal stings and take control of the Earth.

Television shows including “Saturday Night Live” and “The Incredible Hulk” also explored the killer bee theme. Even Star Trek’s usually calm and rational Leonard Nimoy devoted an episode of his popular “In search of” series to the idea.

But in reality, it’s the bees that are under attack and from something much smaller than themselves.

Nature’s most efficient pollinator, and a vital link in honey production, is threatened by a tiny invasive parasite measuring less than two millimetres in length and width.

The varroa mite is an insidious pest that poses a significant biosecurity threat to the common European honeybees whose pollination services add an estimated $14.2 billion to the Australian agricultural and horticultural industries each year.

Fortunately, varroa mite detections in Queensland in 2016, 2019 and 2020 have been met with a swift and effective response, delivering the sweetest of successes.

I’m Brad Muir. In this episode of Turf’n’Surf, we’ll look at the impact of varroa mites on the honey industry overseas, how Biosecurity Queensland has successfully eradicated varroa mites detected in Townsville, and what the Queensland Government is doing to take the sting out of varroa mites.

Program segue: You’re listening to Turf and Surf, the official podcast of Queensland’s Department of Agriculture and Fisheries. Shaping and protecting food and fibre for tomorrow’s Queensland.

Host: Trevor Weatherhead is the chair of the Australian Honeybee Industry Council, an industry body dedicated to the long-term economic viability, security and prosperity of the Australian honeybee industry.

With very good reason Trevor has kept a close eye on the impacts of varroa mite overseas including in America and New Zealand whose honey industries were dramatically affected when varroa became established.

Thanks for joining us Trevor. Firstly, let’s talk about the overseas experience. How did varroa mite get into America and New Zealand and what was the extent of the impact there?

Trevor Weatherhead: With America the main idea of how it got in was probably with bees that came up in the mainland US from South America. With New Zealand there were three thoughts.

One, was that it came in with a swarm that came in on a ship. The second, it was an illegal importation of queen bees and, thirdly, at that time New Zealand was sending a lot of these to Korea, packaged bees, and someone suggested that maybe someone from the United States did a bit of sabotage but within a few years most of the feral hives were gone.

With the beekeepers’ hives, those that looked after their bees, the ones we’ll call the beekeepers, they were able to then switch over to a system where they could control the mite.

The other ones we call the bee havers, they didn’t look after their bees, their bees died so there was a dramatic drop off in the number of hives in America and also in New Zealand.

Host: And that can impact on the honey industry and other horticultural industries?

Trevor Weatherhead: Most definitely. Within New Zealand, within a year the price that was paid to the beekeepers per hive for pollination of kiwifruit doubled.

Host: And it would also impact on production?

Trevor Weatherhead: Certainly for honey production it certainly did. The honey production within America and also within New Zealand dropped at that time, particularly in the early stages when people were working out how to live with the varroa mite.

Host: So what can we learn in Australia from the overseas experiences?

Trevor Weatherhead: The first thing we need to learn is that it will be a process of having to be very vigilant with your husbandry of your beehives, to keep your hives alive.

If you don’t look at your hives very often or if you don’t do monitoring of hives, then you will suffer and your hives will die out and you will probably not keep bees again after that. We also know that there will be an effect on the pollination industry.

There will be less hives available and, also, we know that with the beekeepers that it will spread reasonably quickly because we are a migratory system.

Host: Trevor let’s bring this back to the local markets and give it some local context. What’s at stake in terms of the Australian honey industry?

Trevor Weatherhead: First up, it’s the amount of honey that will be produced that will certainly drop off dramatically.

With the value of the pollination we know that the average value of pollination supplied by honeybees to the horticultural and agricultural industries is about 14.2 billion dollars so there will be a dramatic drop in the number of hives that are available for pollination and the price for those hives will go up and that then could be a flow on effect to the producers where they will have to get more for their crop in order to be able to be viable and in some cases in the early stages there may be some crops that won’t be pollinated and therefore there will be a shortage in some of those crops.

Host: And this is an industry that has already been seriously impacted by natural disasters such as bushfires and floods?

Trevor Weatherhead: Yeah that’s right and also drought is another thing that has been badly affecting our industry as well.

But with the resilience of the beekeepers we know that after the bushfires that the beekeepers were able to, with help from government and supplying supplementary feeding, that they were able to bring their hives back up to strength again.

Host: When we are talking honeybees we tend to think purely in terms of the honey industry, but really it’s not just the honey industry that stands to lose is it?

Trevor Weatherhead: That’s right and so it’s agricultural and horticultural industries that rely heavily on honeybees for pollination.

And particularly those that rely on the feral hives, they’re the hives that are out of the trees in the bush.

And we know from America and New Zealand that those hives within a few years won’t be there so they will be looking for managed hives for pollination.

Host: So our honey bees really are busy little bees. What advice are you giving your members?

Trevor Weatherhead: We’re asking them to be vigilant. We have a code of practice and part of that code is to test annually for any exotic mites and in particular with the incursion management that we have, the National Varroa Mite Eradication Program that is in Townsville at the moment, we’re asking people up there to test their hives regularly.

They can either do the sugar shake or the alcohol wash. The alcohol wash is most definitely the preferred one. So that they can check to make sure because we know that with the mite that is there, which is the varroa jacobsoni which is different to the varroa destructor that is in America and New Zealand, that with jacobsoni we know from the experience in Papua New Guinea it took about 20 years for it to be able to switch over onto the European bees up there.

So we may have that bit of a timeframe to be able to check but we certainly don’t want any of those varroa mites. So if beekeepers check their hives quite regularly and report the details in, then we should have a level of confidence that there are no mites there.

Program segue: This Turf and Surf podcast is powered by Queensland’s Department of Agriculture and Fisheries, shaping and protecting food and fibre for tomorrow’s Queensland.

Host: On this episode of Turf and Surf we’re looking at the impact of varroa mites on crop pollination and honey production, how Biosecurity Queensland has successfully eradicated varroa mites detected in Townsville and what the Queensland government is doing to take the sting out of varroa mites.

Rob Stephens is the manager of the Townsville based National Varroa Mite Eradication Program, a nationally funded program established by the Queensland Department of Agriculture and Fisheries in response to the detection of varroa mites in Townsville in 2016. Rob oversees the team that conducts surveillance following the detection of varroa mites.

Thanks for joining us Rob. Tell us about the team’s work and let’s start at the start. How do varroa mites get here?

Rob Stephens: Varroa mites are parasites that feed on the fat body of the honey bee. Eventually that results in the weakening and often the death of European honey bees colonies all over the world.

The mites are known to carry viruses as well which can affect, adversely affect the honey bee population and Australia is the only populated country in the world that remains free of varroa mites and we intend on keeping it that way.

The mites themselves, they attach themselves to the honeybees and also get inside the hive. Therefore, when the bees enter the country via our ports, they have the potential to bring the mites in with them.

So the bees store honey and this is a food source which allows them to stow away in cargo and allows them to survive the transit from high risk pathways such as somewhere like Papua New Guinea.

So, Townsville is the perfect distance from Papua New Guinea via cargo ship for Asian honeybees to survive and jump ship as soon as they get to port.

Host: Robt you mentioned the link between Asian honeybees and the mites. Why the Asian honeybees and not the common European honeybees host to Varroa Mites?

Rob Stephens: Well there’s actually two different species of varroa mites. There’s varroa destructor which has decimated the European honeybee population all over the world and there’s varroa jacobsoni which usually remains host specific to Asian honeybees.

Thankfully, here in Townsville, we have only been exposed to varroa jacobsoni which is clearly the lesser of the two evils. It is extremely rare for this species of mite to transfer host to European honeybees.

Having said that though, it is definitely possible and our program regularly conducts surveillance on European honeybees throughout Townsville areas to ensure this transfer hasn’t taken place. Because if the transfer were to take place effectively the two mites, the issues are the same and would have the same consequence on our honeybee population.

So fortunately for us, the endemic population of Asian honeybees that originated up in Cairns doesn’t have the mite and it hasn’t travelled this far south to Townsville.

Therefore, by eliminating the introduced population of Asian honeybees here in Townsville, we pretty much eradicated the possibility of the varroa mite remaining.

Host: Varroa mites are tiny, two mil by two mil. How do you go about finding these little critters?  What do you look for, what are the tell-tale signs?

Rob Stephens: Finding the mite itself is extremely difficult and we conduct a range of testing on feral honeybee colonies and managed beehives around Townsville.

This includes a home inspection with beekeepers including miticide strip placement which would kill the mites if they were present in the hive. We refer to that as sticky mat testing.

And we also have been working with local beekeepers and we have been training them on some self-assessment methods which they can use including alcohol washes, sugar shakes and drain uncapping.

The local bee club have certainly done their part as part of this program and is always on the lookout for these signs of high weakness, and we really encourage local beekeepers to report any unusual hives to us directly or via the call centre on 13 25 23.

What has become easier for us though is detecting the primary host species, the Asian honeybees. This is done by a range of surveillance methodologies including floral surveillance, which is just walking around and looking for floral resources and seeing what bees are utilising them.

Setting up sugar feeding stations and if they are successful and the bees come to them we can actually bee-line. That’s a process where the bees are on the feeding station and we can see what direction the bees are flying and then we move the feed station closer and closer to the nest.

We can also measure the flight times of these bees and we can tell how long that nest is away from our feed station. We have also got catch-up boxes set up around the port of Townsville.

And we have also perfected a few other testing methods such as aerial pheromone trapping and also we have really perfected the use of rainbow bee-eater pellets so that’s a little bird that you will often see hanging around power lines around town. It has become a really critical surveillance strategy.

The birds eat the bees but they are unable to digest their wings which is later regurgitated as pellets. These pellets are examined by an entomologist and through this assessment, the bee species can be determined if there are actually Asian honeybees in an area.

The other really important thing for us is good old-fashioned public reporting as well where the public are encouraged to report any unusual bee citing or unmanaged honeybee colony.

Host: I am fascinated by the rainbow bee-eater. It’s a bit like the canary in the coal mine when it comes to varroa mites.

Rob Stephens: Yeah we let them do all the hard work for us so we are definitely out there pounding the pavement looking for bees ourselves, but these birds are designed by nature to find bees. So, if we can find where they are hanging around we can collect their pellets and we can see exactly what kind of bees these birds have been eating.

Host: So just follow the pellet trail. And after you find varroa mites, what are the next steps?

Rob Stephens: Well after we notify the appropriate Commonwealth departments, the peak industry bodies, and our cross-share partners, we work on confirming the extent of the incursion so we do that by surveillance.

Now this is based on the level of risk posed by the detection and that is by factors such as how long the colony was there before it was found, how strong the colony is, is there evidence that the colony has reproduced like swarming.

And we do genetic analysis as well on the bees and we can tell where those bees came from. We also have to confirm what species the mite we are dealing with because there is no visual way to tell two mite species apart, that needs to be done in a laboratory environment.

It’s also important to confirm whether any virus come with those mites. So, they’re the first steps. Once we have established that in most scenarios we would start surveillance at the point of detection and we would be working outward, usually up to two, two and a half kilometres.

Host: Rob you mentioned you work closely with industry and beekeeper groups. How can members of the public help to protect against Asian honey bees and varroa mites?

Rob Stephens: The public can help by simply just checking their own backyard and their places of work for signs of any unusual bee activity or any unmanaged colonies of honeybees.

So, anything they think is a little bit out of place, if there’s any actual colony of bees we would definitely like to see it and get species confirmation to know if it is a possible Asian honeybee or if it’s just a regular European honeybee.

Because the more eyes we have got in the field, the easier it is for us to limit the spread and also ensure that the eradication program is on track.

Program segue: You are listening to Turf and Surf, the official podcast of Queensland’s Department of Agriculture and Fisheries shaping and protecting food and fibre for tomorrow’s Queensland.

Host: On this episode of Turf and Surf, we’re looking at the impact of varroa mites on crop pollination and honey production, how Biosecurity Queensland has successfully eradicated varroa mites detected in Townsville, and what the Queensland Government is doing to take the sting out of varroa mites.

Rebecca Sapupo is Biosecurity Queensland’s manager, plant incident response and preparedness, the group that coordinates responses to plant biosecurity incidents in Queensland.

Welcome Rebecca, I mentioned that the National Varroa Mites Eradication Program was established following the detection of varroa mites in Townsville in 2016. How was the program established and what is its aim?

Rebecca Sapupo: There are a number of sort of national systems that look out for key biosecurity threats, the plant industries. And we use those national systems to help guide our responses when we get a new detection of something nasty.

So in 2016 when varroa mites was detected at the port of Townsville, it activated those national systems and something called the emergency plant pest response deed.

That deed provides us with a framework for the kinds of information that we need to gather in the early stages of the response and it also gives us guidance about how we might establish a response in consultation with state, federal and government parties as well as affected industry parties so that everybody comes to the table very early on in the response to learn about what is happening and to help develop a strategy to eradicate the pest.

Ultimately, Queensland is a lead jurisdiction for managing that pest and we have got lots of experience within Biosecurity Queensland about the establishment of emergency responses to try and contain these new pests and diseases that might turn up in Queensland.

And we drew upon that to very quickly establish a team of people based in Townsville who could start doing surveillance, looking for the pests, working out how widely spread it was and gathering information that all of our partners needed to decide whether or not we could eradicate the pest.

As we moved forward we had lots of support from local beekeepers and affected industry parties and we built a system and a program that was technically designed to find the varroa mite and to destroy it and to prove that our eradication attempt had been successful.

Host: You make a good point that it is a national program so tell us about the program’s elements and how do they all come together to keep Australia free of varroa mites?

Rebecca Sapupo: So when we build a biosecurity program there often integrated systems. There’s many elements that need to work together to achieve eradication.

So the first thing we needed to do was to design a system of what we would call surveillance, finding the host species, Asian honeybees and testing them to see whether or not they were infested with varroa mites.

And then once we found them, it was important that we destroyed them promptly through you know finding them in cracks and crevices in people’s homes or in the hollowed out tree trunks.

It is not an easy thing, but we had to make sure that we got all the bees from each of those Asian honeybee nests to make sure that we got rid of varroa mite in those instances. And I think with the Townsville response we had to do that in 10 different locations where we found Asian honeybees.

We also have very strong public awareness campaigns. Because we were working in the Townsville local government area and in an urban area, we had loads of people, potentially eyes on the ground that could help us identify where those bees and the mites were. So it was really important that we got the community on side and engaged. And the Townsville folks really came out in droves to help us with that.

We had very, very strong support for the program and lots of public reports that we could follow up on to help us make sure that we found all of the bees and the mites. We also had great support from local beekeepers who let us monitor their hives of European honeybees to make sure that the mites weren’t present in those areas as well.

So it was a truly sort of integrated system of search and destroy. And then once we considered that we got rid of all the Asian honeybees and varroa mites that we were aware of, we initiated a program of continued surveillance and public awareness.

So I think it was about two years, so the middle of 2019, to make sure that we gathered a huge body of evidence that conclusively proved that the host and the varroa mites had been eradicated from Townsville.

Host: So that’s great news that the program has had success in eradicating varroa mites. But you did make the point that it is an ongoing process and continued vigilance is critical to protecting the Australian honey industry.

Rebecca Sapupo: That’s right, and I think Asian honeybees can travel on shipping containers, from international ports.

And so in Biosecurity Queensland, we work very closely with our federal counterparts, the Department of Agriculture, Water and Environment, who are responsible for that border surveillance and keeping these pests and diseases out of Australia.

And particularly with the Townsville port, seems continued vigilance is really required. But I think the other good thing is that, through the life of this program since 2016, Biosecurity Queensland and the National Varroa Mite Eradication Program in Townsville has built up a wealth of knowledge and proven eradication techniques.

We know that if it turns up again we have got a good shot at eradicating it in future.

Host: Rebecca, where can people find out more about Asian honeybees and varroa mites?

Rebecca Sapupo: There’s lots of information on the Department of Agriculture and Fisheries website, or they can call 13 25 23 and quite often we do put posts on the Biosecurity Queensland Facebook page so they can sign up to follow that.

Program outro: You’ve been listening to Turf and Surf. Turf and Surf is produced by the Queensland Department of Agriculture and Fisheries. For more information or to subscribe, visit our website at daf.qld.gov.au.