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Argentine ant

Argentine ant.Argentine ant. 

Common names:
Argentine ant

 

Scientific name:
Linepithema humile

 

Regional classification:
Control of pest ants under community control schemes and prohibit distribution

 

 

 

Description

Argentine ants:

  • Are about 2mm to 3mm long and are a pale honey-brown colour (unlike most house ants, which are black).
  • Eat sweet things, but also seek out protein (found in meat, eggs, fish), and will consume dead insects and other small animals.
  • Travel steadily in defined continuous trails up to five or six ants (or 2cm) wide.
  • Walk or swarm over objects, people or animals, rather than skirting around them.
  • Like warm, dry places and nest almost anywhere, but especially on the ground under timber, metal or concrete, plant pots, boats, caravans and tents.
  • Are excellent infiltrators! Screw-top jars, closed microwaves, stoves and fridges do not always stop them.
  • Commonly found on citrus trees along with high numbers of aphids. The ants farm the aphids for honeydew.

 

Argentine ants are about 2-3mm long.Argentine ants are about 2-3mm long.

If you suspect you have Argentine ants on your property bring a sample in a well sealed container with your name, address and phone number to the Department of Conservation or the Northland Regional Council.

 

Please freeze the container of ants before bringing it in for identification.

 

Why are they a problem?

Argentine ants are among the 100 most invasive species on Earth. First discovered in New Zealand in 1990, they are believed to have reached Northland via potted plants, freight or wood and are now found throughout the region, especially in urban areas.

 

Argentine ants can form super-colonies of immense size and threaten the region’s environment and economy as well as the lifestyle Northlanders enjoy. An aggressive species, Argentine ant bites are not poisonous but can be irritating and cause allergic-type reactions in some people.

Map of Argentine ant infestations in Northland.Map of Argentine ant infestations in Northland.

 

In New Zealand Argentine ants threaten native insects, lizards and native birds, either attacking them directly or by competing for food like nectar and honeydew. Overseas studies have shown that Argentine ants can have a significant negative impact in natural ecosystems, as they affect natural processes from the soil right through to insect communities, and even the pollination of flowering trees.

What can I do?

Stop Argentine ants spreading

  • Check potted plants for ants before moving. If plants contain ants, treat with AntstopG or a similar contact insecticide.
  • Check garden soil and bark, and building materials before moving.
  • Check camping gear, before going to a campsite.
  • Check cars, caravans, campervans, boats and trailers particularly if they’ve been in the same spot for some time. Spray the tyres with repellent such as Ant Ban.
  • Use a repellant on recycle and rubbish bins.

 

Make your property less attractive to ants

 

Indoors:

  • Where ant trails enter your house, use a permethrin spray (like Ant Ban) on surfaces that will not be affected by weather. Block off obvious entry points.
  • Keep all at-risk foods (especially sugary ones and proteins) in sealed containers in your fridge and check fridge doors to ensure seals work properly, particularly on corners.
  • Remove crumbs, including from microwaves and stoves.
  • Clean surfaces favoured by ants with lemon juice, soapy water or diluted vinegar, eucalyptus or tea tree oil.
  • Put pet food bowls in a tray of water.
  • If you have a problem with ants in bedrooms, move beds away from walls, keep sheets and blankets up off the floor.

 

Outdoors:

  • When gardening, cover up disturbed nests until they can be treated.
  • Don’t leave food scraps or food sources lying on the ground, especially near your house.
  • Reduce moisture sources, for example leaky taps, irrigation hoses, etc.
  • Trim trees near your house to reduce ant access.
  • Spray affected trees for scale insects and aphids
  • Stand recycle and rubbish bins and picnic table legs in water with a little Janola added.

Recommended control methods

Argentine ants are extremely difficult insects to control. An effective bait for Argentine ants is Xstinguish™. For information on pricing and local agents for this product contact ‘Flybusters’ on 0800 837 070.

 

There are also two sprays available but these can only be applied by qualified contractors with approved handlers certificates.  Details for these sprays and local contractors are available as follows:

 

Biff Ant® - Key Industries phone: 0800 539 463

Termidor® - Garrards phone: 09 526 5232 

WARNING: Do not try to eradicate Argentine ants with other ant control products. Not only do these products not work they may also disturb the queens of colony which can split up the nest allowing the formation of multiple new nests elsewhere.

 

About Xstinguish™Argentine ant bait

 

This pale green paste carries the toxin ‘fipronil’, which is also used in flea treatments for cats and dogs. At the concentrations used it is not harmful to human, cats, dogs or birds.

 

Ants are attracted to the Xstinguish™ bait, which they carry off to their nest for the rest of the colony (including queen and young) to share. This efficiently destroys the colony with minimum impact on other organisms. In trials, even a single application of Xstinguish™ has shown a dramatic reduction in ant numbers. It may take an hour or so for the ants to start taking the bait, and up to 6 to 8 hours for it to spread amongst the whole colony. You can still eat from your garden - just wash any plants that you pick that day for consumption.

 

How to lay Xstinguish™ bait

  • Check with neighbours. If they have an Argentine ant infestation too, properties should be baited on the same day for maximum effect.  If possible, plan baiting to coincide with high levels of ant activity, for example mid-summer. (Ants forage in the garden in summer and most nests will be sited there.)
  • Using a caulking gun to squeeze out the paste.  Lay bait in small ‘blobs’ similar to the amount of toothpaste you would put on your toothbrush. A 325 gram tube should cover 1100m2 of flat land.
  • Squeeze bait out onto the ground in a grid pattern at regular intervals of 1m to 2m. In bark gardens, the spacing should reduce to 1m x 1m, but in open grass areas, it can increase to 2m - 3m.
  • Target cracks and crevices where Argentine ants have been seen. Baits can actually help identify where the nests are sited. Follow the trail from the bait to find the nest. Put baits as close to the nests as possible.
  •  Try not to disturb nests while you are laying bait.  Disturbing them causes the ants to move their nests rather than feeding on the bait.
  • If you see ants up trees, apply bait at the base of trees and along branches, where you can reach, if heavy trails are sighted.
  • Put bait in shady places to help prevent evaporation (tip: cover it with a large leaf).
  • Do not lay bait inside buildings, as the bait will draw all ants inside.
  • Keep other animals away from treatment area for at least four hours. While no harm will come to them if they eat it, you will have to re-bait.
  • Placing the bait in hose pipe or irrigation tube will help prevent the bait from drying out and stop animals eating the bait.
  • NOTE: the bait is toxic to fish and other aquatic organisms, so do not lay within at least three metres of ponds, streams and stormwater channels such as gutters.
  • Keep any left over bait in the fridge (remains viable for three weeks), away from food, and use it to treat remaining nests.
  • Re-baiting will be needed about 8-12 weeks later (late summer) to kill any survivors/subsequently hatched ants. Watch for pockets that might have been very heavily infested as these may need to be re-treated.

 

Disclaimer:
The information in this Guide has been written in good faith.While every endeavour has been made to ensure that the information in this Guide is accurate, the Northland Regional Council accepts no responsibility for any error or omission in these pages, nor for the use or misuse of any pest management  product. Users must observe safe practice guidelines and any directions on the product label. If in doubt, contact the product supplier for advice.

 

Find out more: Download pest animal control publications

More information

For further information or control advice please contact Steve Henderson at the Northland Regional Council on 0800 002 004.