What does it look like?
Argentine ants are 2–3 mm long and a honey-brown colour (rather than black). Foraging ants move steadily (not slowly) in wide trails that can often be seen going up trees or shrubs, especially if these are flowering. They are aggressive and territorial and will bite (they are not poisonous). They have a slight greasy odour when crushed, as opposed to the strong formic acid smell of some ant species. Argentine ants are frequently associated with areas of human settlement. In New Zealand, Argentine ants have invaded native habitats including scrub, mangroves, coastal forest and the edges of native forest. They are currently found in Auckland, Northland, Waikato, Bay of Plenty, Hawke's Bay, Wellington, Nelson, and Christchurch.
Why is it a problem?
Argentine ants favour warm, dry and elevated sites in urban and natural areas, often in soil. They are moved around by people (e.g. in potted plants, beehives, soil etc.).
Nests of Argentine ants have multiple queens and are capable of multiplying into huge numbers in a very short time, and will form super-colonies.
They are a household and garden pest and will kill and displace native invertebrates, as well as consuming the food sources for our native fauna. They will eat lizards, bird eggs and young chicks.
Control methods
Pesticide control
Fipronil based baits and pesticides are recommended. For larger super-colonies, a coordinated community response will be needed. Seeking advice from pest control experts familiar with Argentine ants is advised before DYI control is attempted.
Bait needs to be set at multiple bait stations near established trails, especially along edges of paths, structures, fences, garden timber borders, rock walls. Follow product instructions.
Prevention
Nests can easily be moved from their original location. Check potted plants; garden soil, bark, and building materials, especially in bags; camping gear; inside kayak and dingy cavities.
Related links
Management Programme
Unwanted Organism
An unwanted organism is any organism that's capable of causing harm to natural or physical resources (like forests and waterways) or human health. A number of introduced pests in New Zealand are classed as unwanted.
