DESCRIPTION
Argentine ants are:
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Very ordinary-looking, small brown ants.
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Small and slender, 2.6 to 3.2mm long.
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Dark brown in colour.
The worker ants:
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Are uniform in shape and size
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Move in well defined trails.
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Have a slight greasy, musty odour when crushed.
Argentine ants do not possess a sting but will bite readily, although the bite is not painful.
SYMPTOMS
Continuous well-defined trails. The ants will often readily climb onto a person’s hand when it is placed in their trail. Many other ant species will not do this.
Argentine ants are typically confined to urban areas and they nest outside buildings, at the base of trees or in the tree itself, along the edges of paths and in lawns and garden beds. They will thrive in swamps and low-lying areas where moisture is plentiful.
Populations peak from January to June, and they can be very invasive, coming indoors in large numbers in their search for food and moisture.
These ants are ecological pests. They attack nesting birds, hatching eggs and other native fauna. Argentine ants will quickly eliminate other ants from an infested area — especially native ants which play an important role in the ecosystem. They will rob commercial beehives and are significant pests in orchards and sometimes larger farms.
TREATMENT
Physical exclusion: Sealing the cracks and crevices through which they are entering. Argentine ants are resourceful, however, and are likely to find alternative routes which will require similar treatment.
Chemical exclusion: An insecticide barrier can be sprayed around the entire outside perimeter of the house, including doorways and window sills. These chemicals are repellent and have reduced toxicity to people and pets. They are ideal for use as barriers.
Attention needs to be paid to situations which could allow the ants to bypass the barrier, for example, foliage in contact with the building or additions to the building like patios and pergolas which could provide an alternative route.
The other strategy, in severe infestations, is to reduce the argentine ant population using insecticide spray treatments.
The following areas also require treatment:
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all nests and ant trails
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edges of paths and driveways
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garden beds adjacent to the building
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butts of all trees and large shrubs
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areas around rubbish bins and taps, to isolate the ants from these food/water sources.
Argentine ants remain the most difficult common pest ant to control. Once cleared from an area, argentine ants can quickly re-colonise it from untreated neighbouring properties. This can occur within two weeks.