Source: Radio New Zealand
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The battlelines have been drawn in Biosecurity New Zealand’s war against the yellow-legged hornet, but there’s some suggestion they should be widened before a population takes hold.
Currently, trapping has been extended out to a five kilometre radius around the concentration of the hornet detections in Auckland’s Glenfield and Birkdale, using a combination of carbohydrate and protein traps.
To date, there have been 29 confirmed queen hornets found (based on specimens), according to Biosecurity New Zealand.
The agency said 19 of the 29 confirmed queen hornets were found with either developed nests or evidence of nesting.
Additionally, seven worker hornets were found in nests.
Northland conservationist Brad Windust said authorities need to look at casting the net wider to 30km ahead of summer.
He said the coming months were pivotal for the goal of eradication and the prevention of the hornets spreading to other regions.
“We need to give out thousands of traps to people in a 30km radius with clear instructions and bait.
“It will only take two queens to fly outside the current 5km radius monitoring area they have at the moment and we would have lost it because each queen after she makes her nest drops hundreds of queens in the autumn and they can disperse up to 28km.
“We also want them to give out Vespa catch traps to all the beekeepers and orchardists in the North Island as a monitoring tool, because there’s a real chance that some of these hornets got moved while they were hibernating in the winter last year.”
Biosecurity New Zealand north commissioner Mike Inglis said the fact they were finding more hornets showed surveillance efforts were working.
He said they’d adjust their hornet response activities, including extending the trapping radius, where required based on their technical advisory group (TAG) advice alongside the input of our own experts.
“The 5km tapping radius was decided on based on advice from the TAG. It is a multi-prong scientific approach to trapping, as guided by our international experts with actual on-the-ground experience managing the pest. However, our public awareness push extends throughout the country.
“We have a national advertising campaign in the market urging the public to report suspected sightings. We are asking residents to check their properties for any hornets or nests and providing information where to look, including how to make and monitor your own trap.
“We are also working closely with the bee industry, including enhanced hive surveillance and we have produced a series of key documents for beekeepers around trapping, surveillance and reporting. All of that information is also available on our website.”
Inglis said on-the-ground surveillance was an important tool for detecting hornets and had been expanded since the beginning of the response.
“We have increased the number of traps by more than five times from the early numbers, to more than 600 and we are adding additional traps as more hornets are found. We are also doing property-by-property searches within 200 metres of confirmed finds. We’ve done more than 2200 property checks for hornets and nests and that number grows every day,” he said.
Inglis said genetic testing indicated the hornets were closely related, suggesting a small, contained population.
Victoria University entomologist Phil Lester said Biosecurity New Zealand were acting appropriately with their action around trapping and searching areas for ground nests.
“I think the ground teams that are working from MPI are doing a really good job. So clearly they’re finding this, they’re putting a lot of effort into it.
“They’ve increased the amount of people that are on the task and are doing well, but I think we probably need to have more people out there, more boots on the ground to be able to look for these hornets and get them while we can.”
Lester said authorities will need to change tact ahead of the summer months.
“Having traps out, having people looking for nests and workers is awesome.
“In addition, at that stage let’s do the hunting for nests up the top of trees and that sort of thing where they’ll be at that time. So the tipping point really comes at, well, we’ve got to spend, hopefully get them all this summer.”
Lester said it was difficult to know just how far the pests may have travelled since arriving in Auckland.
He said the 5km radius advice at the moment is based on international advice that Biosecurity have had.
“There’s lots of work overseas that is looking at how quickly does an invasion front move, so that work is where the 30km to 80km to 100km comes from and that’s where you’ve got a whole bunch of nests that are sending out new queens every autumn that are going some distance.
“We’re not in that situation. So we’re in a situation where we’ve probably got one nest that sent out some queens last autumn.
“So how far have they moved? That’s the big sort of question that is kind of unknown.”
He said even if authorities were unable to complete eradication this summer, it’s not too late.
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– Published by EveningReport.nz and AsiaPacificReport.nz, see: MIL OSI in partnership with Radio New Zealand
