Environment Waikato wants to eradicate the world’s most invasive and problematic ant species from Morrinsville.
This week’s Biosecurity Committee meeting heard that Argentine ants were very aggressive insects which have inhabited an 85 ha area of Morrinsville, including the dairy factory and residential areas. The ants can eliminate other ant colonies, and eat other insect species and earth worms. Their effects on horticulture, commerce and conservation are a serious cause for concern.
Environment Waikato commissioned a survey in late January, which found that the railway track and Piako River appeared to be acting as a local barrier preventing southerly spread of the insects. Residents and businesses would experience more disruption with ants foraging and they were likely to become widespread.
The current size of the infestation presented a challenging management proposition, Biosecurity Group Manager John Simmons said.
Environment Waikato could choose to do nothing and suffer the consequences, undertake a direct control programme with associated costs and possibly a new toxin, or undertake progressive control to reduce the size of the infestation with a public awareness campaign and landowners taking responsibility.
Argentine ants had not been declared an unwanted organism under the Biosecurity Act so those powers were not available, and as there were no known eradication methods MAF and the Department of Conservation had not pushed for the declaration. MAF had recommended a national containment strategy with eradication at priority sites, but had funding declined for research into identifying ‘risk pathways’.
Environment Waikato had declared the ant a ‘potential pest’ in the Regional Pest Management Strategy which justified direct control. An eradication or progressive control programme would require considerable planning, funding and resources over the coming year.
The Committee recommended undertaking an awareness programme in Morrinsville, seek approval and funding from MAF to undertake a joint eradication programme, or if that failed, investigate the feasibility of a direct control programme to reduce the infestation and prevent new incursions.