Browsing ants identified in Darwin port region
Following the positive identification of browsing ants on 6 August 2015 within a secure section of Darwin Port, the Department of Agriculture and NT Department of Primary Industry and Fisheries have now identified browsing ant on a further two sites in nearby areas.
Browsing ants (Lepisiota frauenfeldi) are exotic and have not established in Australia. They form large colonies and eat and displace native ant species, as well as other insects in the infested area. They are not harmful to humans.
Following the first detection, the Department of Primary Industry and Fisheries conducted comprehensive surveillance on 14 sites where freight and containers had been moved to, including both visual surveillance and the use of ant baits to attract and identify browsing ants. This identified potential colonies at two additional locations.
How are browsing ants being managed?
As these three sites are located within the Darwin port region the Department has responded immediately to reduce the risk of spread of browsing ants by providing a direction to the landholders to stop the movement of any cargo, materials or equipment off or associated with those portions off the site.
These sites have been secured and freight movements have been limited into and out of these areas. As these sites are on private land, their locations are not able to be identified.
This week the department setup a Local Control Centre (LCC) at the Berrimah Farm to put into place the necessary management and control measures to destroy the ant colonies at the three current infected sites whilst further surveillance is being conducted.
The same control measures that have been successful applied in Perth, the location of the only other browsing ant outbreak in Australia, are being used in this response. This includes the application of a granulated product specifically formulated for browsing ant, with a follow-up ground spray of a commonly used ant treatment.
Both of these products are registered and used in either commercial or domestic situations already, so there is no risk to workers or the public.
How long will surveillance continue for?
Ongoing surveillance will be conducted over the next month at other sites that are identified through our tracing efforts, which may reveal further detections.
The area will remain under ongoing monitoring for the next two years before a successful eradication can be declared.
The only previous detection of these ants in Australia was at Perth Airport in 2013 resulted in approximately 60ha being treated and is on track to declare eradication
This detection and rapid response demonstrates that the Commonwealth and NT Government biosecurity systems operate efficiently.
About browsing ants
Browsing ants are a slender inconspicuous ant, and shiny uniform dark brown in colour. They are 3–4mm in length with long antennae and long legs, and run about in haphazard manner when disturbed. They are not harmful to humans.
They are commonly found in our nearest neighbour –Timor Leste and in Malaysia.
Browsing ants are an arthropod scavenger, which can form multi-queened, super-colonies.
In high populations this pest can displace native ant species and most other invertebrates. They can also cause damage to plants and landscaping. Browsing ants are ideally suited to Australian conditions.
Businesses that are in the Darwin area and have received freight or containers direct from the Quarantine Approved Premise (QAP) of the Darwin Port are encouraged to keep an eye out for these ants. If you think you’ve found a Browsing ant population, it is important that you report it to the Exotic Plant Pest Hotline on 1800 084 881 as soon as possible.
How likely is it that this ant will spread?
On the basis of the current detection and the movement restrictions we have put into place we are confident we can contain and eradicate browsing ant from these sites.
Where do you think the ants came from?
The source of the initial infection may never be known. This will be considered in the ongoing work of the Local Control Centre.
Can this ant be eradicated?
These ants can be eradicated, which has been demonstrated overseas, as well as the instance in Perth.