Positive results from latest Argentine ant program assessment

The latest assessment of Norfolk Island Regional Council’s (NIRC) Argentine ant eradication program shows positive results across several of the identified ant infested zones.
As of September 2024, there are twenty-two known Argentine ant locations areas across Norfolk Island, covering a total area of approximately 560 ha. The ant has been declared eradicated from zones 2, 6, and 8 (see image) and will shortly be declared eradicated from zone thirteen if no infestations continue to be found.

A further five zones are also showing positive signs of eradication as no Argentine ants have been found in these zones for over 12 months. More than 60% of the areas infested with Argentine ants has been treated, which is the largest amount the program has ever achieved. Thanks to the rigorous work of the AAEP team, another eight zones now contain only small infestations, reduced from their former size and number.

The focus for the coming six months will be on post-treatment assessments (by both dog and people) in areas ants have been found in the past 12 months and also around the perimeter of the perceived zone limit.

Council is awaiting delivery of a new aerial treatment and will be trialling its efficacy on arrival to compare it with previous products used. The new product has a lower concentration of fipronil and is less likely to attract bees. It has a thicker consistency that should work better on windy cliff areas.

Based on current information about the new treatment, the AAEP team anticipates that the result will be favourable, allowing treatments to be carried out in some of the zones that still contain small and persistent ant populations and a number of cliff areas that we haven’t been able to successfully treat to date. Further aerial and ground treatments will be conducted once the results of post-treatment assessments have been completed.

Success in the eradication of the Argentine is reliant on a number of crucial elements, including sufficient resources, multiple treatment methods, rigorous and timely post treatment assessments with both people and the detector dog and of course the cooperation and support of landowners and the community.

NIRC’s Argentine Ant Eradication Program staff and contractors work with the guidance of the Commonwealth Scientific and Industrial Research Organisation (CSIRO) to conduct targeted baiting in Argentine ant infested areas. The program is currently funded through the Department of Infrastructure, Transport, Regional Development, Communications and the Arts (DITRDCA).

Image caption: The map indicates the extent and location of known Argentine ant infestations on Norfolk Island as of September 2024. Green zones mark areas that have undergone treatment and are now undergoing post-treatment assessments. Red zones are those that have not yet been treated and the ants remain unmanaged, with the exception of zone 12 and 19 (cliff area) which has recently had treatments completed. Orange points are detections made between July 2023 and about February 2024 that have been treated, pink points are detections made from March 2024 that have been treated, and red points are un-treated Argentine ant detections made in early August 2024