More beehives will be destroyed in New South Wales after a new detection of varroa mite prompted the expansion of an eradication zone.
The mite was discovered in a hive at a property near Cessnock, north-west of Newcastle.
The property is located in the surveillance, or "purple" zone, just outside the "red" eradication zone.
The Department of Primary Industries says the new detection has been directly traced to an infested hive inside the eradication zone.
"We're still trying to determine exactly what has occurred, but we believe that this person has a close relationship with a previously known infested premises," DPI incident controller Lloyd King said.
"We've found out that they're actually hives that were moved from that known infested premises in the last eight or nine months that we didn't previously know about.
"This particular case we'd actually been on and surveyed it … because of their link to a known infested premises.
"It's only been when we've actually gone back there that more has been revealed about where those hives originated from."
More hives to go
The red zone will be expanded to include the Cessnock area, meaning more hives will be destroyed.
Hundreds of hives to be destroyed since the mite was detected at the Port of Newcastle in June, including hives at a world-class bee research facility near Paterson in the Hunter Valley.
Mr Lloyd said the new detection showed varroa mite was in the region before the detection at the Port of Newcastle.
"We know that the first place that we found it was the Port of Newcastle, but we're still pulling together how it got to that site and from where it came," he said.
"The more surveillance we do in the purple zone, and the more information we've gathered from the red zone … gives us a very firm idea that [the Port of Newcastle] definitely wasn't the point of entry."
Industry concern
The latest detection brings the total number of infestations to 103.
NSW Apiarists' Association president Steve Fuller was glad the link was traceable but said the case had triggered nerves within the industry.
"It makes me wonder, and it makes the industry really scared … how many other ones are out there," he said.
"At this point in time I think it's still a bit too early to move to management, but it's going to make them rethink the whole system."
NSW Agriculture Minister Dugald Saunders said the detection showed the importance of maintaining surveillance in the region.
He said the hives on the property were being destroyed.
"We will continue to monitor the rest of that purple zone to limit … possible spread," Mr Saunders said.
"It's not a significant infestation at this particular site — it's a small one, but it just does show we need to keep doing what we have been doing."
