Argentine ants

The Argentine ant, one of the world's most invasive and problematic ant species, has spread to Taranaki.

Photo source: joycegross.com

This page contains information about Argentine ants and advice on controlling them.

To obtain bait for Argentine ants, go to the Flybusters Antiants website to identify the products that you wish to purchase (see link in navigation panel at right).

Telephone Flybusters Antiants on 0800 DIYPEST (0800 349 7378) to place your order and identify yourself as a Taranaki resident to get a 15% discount.

About the Argentine ant

The Argentine ant is native to Argentina and Brazil, but is now well established in California, Europe, South-Western Australia, Chile and New Zealand.

Argentine ants (Linepithema humile) are very aggressive insects. Although they are not poisonous, they do bite people.

They are capable of completely eliminating other types of ant colonies, and also destroy and eat other insect species and earthworms. They particularly like sweet food, and tend populations of aphids and scale insects on plants, using them as a source of honeydew while protecting them from their natural predators.

Unlike other ant species, Argentine ant colonies co-operate with each other, and can combine over winter into super-colonies. This makes them more competitive and aggressive towards other insect populations through their sheer numbers.

What do they look like?

Because they are so small, the best way to tell Argentine ants from other ants is by their colour and their trails.

The wingless worker ant (most commonly seen) is light to dark honey-brown, and 2-3 mm long (most other common household ants in New Zealand are black).

Argentine ants are highly active in searching for food, their trails are often five or more ants wide and may travel up trees or buildings. Other species of ants don't tend to climb trees, and would not have such strong trails unless they were moving a nest (in which case you would see ants carrying their eggs).

If you squash an Argentine ant there is no strong formic acid small as there is with some ants.

If you require assistance to identify Argentine ants, please phone the Council on 06 765 7127.

The Landcare website also has helpful information on identifying Argentine ants. See link in navigation panel at top right.

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Where have they been found?

Argentine ants were first found in Auckland in 1990. More recently, they have been found in Northland, Waikato, Bay of Plenty, Wellington and Christchurch.

In 2006, Argentine ants were discovered in Taranaki. To date infestations have been identified in Waitara, Bell Block, Oakura, New Plymouth, Patea and Waverley. However, their distribution in Taranaki is likely to be more widespread than this and new infestations are expected to be discovered in Taranaki over time.

Although Argentine ants breed prolifically, they do not swarm (fly off to establish new nests). This means that they do not spread rapidly, but when a building or property is infested it will have a very high number of ants and colonies.

Their natural rate of invasion is a few hundred metres per year, but the main way they spread to new areas is through transported queens and nests. This often occurs when a potted plant is moved with a nest in its soil, or if nests are established on vehicles and freight.

Why are they a threat to New Zealand?

• Left unchecked, Argentine ants will become a major household and garden pest. Their huge numbers (up to six nests per square metre) mean a huge appetite, and they will utilise just about any food source they can find. They are even known to make their way into microwaves, refrigerators and screw-top jars. Argentine ants are now considered to be one of the world's worst household pests.
• Argentine ants threaten native invertebrates wherever they invade. The ants are very aggressive and kill or drive away other insects. In South Africa and the USA, Argentine ants threaten endangered species that rely on native ants for food, pollination or seed dispersal.
• Argentine ants climb trees and can kill baby birds in the nest. The ants are also very active foragers, and compete strongly with other species that feed on honeydew or nectar, including insects and birds.
• Argentine ants 'farm' populations of aphids, scale insects and other pests that produce honeydew. The ants protect the insects from predators, and will even move them to new plants or to new parts of the plant. This is particularly serious for organic growers and those using integrated pest management, who rely on predators to control these pests. Argentine ants have also been reported to feed directly on fruit crops, and their sheer numbers can damage flowers and reduce fruit set. They are one of the worst pests of citrus in Australia, and a serious pest of viticulture, avocado and tomato crops.
• Argentine ants are not found in some Asian countries. If they become established in New Zealand's horticultural areas and near our export ports, they may impact on our trade with those countries.

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Controlling Argentine ants

To destroy or control Argentine ants use Xstinguish® Argentine ant bait.

Lay bait in a grid pattern by applying a blob that would fit your toothbrush 1.5 to 2.5 metres apart. Never lay the bait inside buildings, only treat the outside soil areas and around the edge of your house.

The bait is best laid on a warm day but out of the sun (eg, in cracks, under bark in bark gardens, under stones, between grass and concrete etc) - otherwise it may dry up too quickly for the ants to have time to take it.

Xstinguish® Argentine ant bait

Xstinguish® Argentine ant bait is available from Flybusterrs Antiants (0800 349 7378). There is a 15% discount if you identify yourself as a Taranaki resident.

It is a very effective ant bait and one 325gm cartridge is generally enough to treat the average house section. You only need to lay bait on your section, as it will draw the ants to it. However, if neighbours co-ordinate control to bait a larger the area, the programme will be more effective.

The active ingredient in the bait is Fipronil, which is used also in cat and dog flea treatments and cockroach bait. There is no significant risk to human health.

At the concentrations used and with the nature of the bait, there is no effect on cats, dogs, birds and honeybees.

The paste bait is placed in small 'blobs', 1.5  to 2.5 metres apart in a grid pattern.

Tips for applying Xstinguish® bait

• A 325-gram tube will cover 1100m
• Treat on a warm dry day and with no rain forecast within 24 hours
• Ensure cats and dogs are inside for the first four hours as they will get to the bait first before the ants have eaten it
• Do not lay bait inside buildings - only treat ant habitat outside
• Do not use any chemical sprays inside or outside prior to treatment as the ants are sensitive to chemicals and will not take the bait where a chemical has been laid
• When cutting the applicator tip, ensure you don't cut too large an opening - cut approx 1 cm from the tip
• Apply bait in small amounts - equivalent to the amount of toothpaste you would put on your toothbrush
• Apply bait in a grid pattern of approximately 1.5 - 2.5 metres apart




• Apply bait out of direct sunlight, in cracks and under bark etc or cover with a leaf, stone or some bark to prevent the bait drying out
• If applying to open grass areas, increase spacing to 2-3 metres
• Do not lay bait on open unbroken concrete or tarmac areas - in this case apply along the edges or in any cracks and crevices where you see ants running
• If treating on a hot day (more than 25 degrees ) treat early morning or later in the day as ants retreat to the nest at around 24 degrees and will not feed on the bait
• Lay bait at the top and bottom of retaining walls
• Keep bait at least 3 metres from outdoor fishponds as the bait  is toxic to fish
• Treat pot plants as well - if inside pot plants are infested move outside prior to treating
• Keep any leftover bait in the fridge (three weeks maximum) and use to treat any remaining nests
• Ant Stop G granules should be spread around property boundary to slow any infestation from neighbouring properties
• For best results talk to your neighbours about working together to cover the largest area possible.

For further advice or information, contact:
The Pest Animal Management Section

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