How to get rid of ants

Ants can certainly be annoying….. and as many have found out, ant control is not always that easy! Their small size, large numbers and complicated social structure make controlling ants a continuous battle. Identifying the ant species present can certainly be useful, as it helps determine the potential nest locations and likely size of the nest.  However, even without identifying the species present, there are some basic principles of ant control that will allow the homeowner to get on top of almost any ant problem…..although it sometimes takes a bit of patience and a bit of persistence!

New Zealand is unusual in that it has very few ant species – it only has around 40 species of ant and 28 of these are introduced species. Most of the pest ants are introduced species, with only the Southern ant the only native species which is really considered a pest.



Black house ant


white footed ant


Pharaoh ant




big headed ant





  • Ants are a typical insect with 3 body segments and six legs.
  • Ants are often called social insects as they have different types of ants performing different roles within the colony.
    • The reproductive ants (kings and queens) tend to be the largest ants in the colony. These are the winged ants that you may see leaving the nest in large numbers to start a new nest.  They mate and lose their wings before starting a new nest.
    • The majority of ants in the colony are the workers which carry out most of the day to day work. For some species the workers are all the same size, for others the workers can vary in size.
    • Some species also have a soldier caste to help with colony defence – these tend to be larger than the normal workers.
  • Ants hatch from eggs into larvae and then pass through a pupal stage before turning into adults ants. Eggs, larvae and pupae are normally found in the nest, but are sometime visible when being carried by worker ants if the nest is on the move.


  • Ant infestations inside the home are pretty obvious…. you see ants! Often, these may be ants nesting outside coming in looking for food and moisture. The key action is to act as soon as you see them. If you leave it a few days or weeks, they will establish your home as one of their main feeding sites and will try and keep coming back, making them more difficult to control.
  • If you find ants in your house and cannot find an entry point from the outside, the ants may be nesting in or under your house. They quite often nest in wall voids, roof spaces and behind cupboards. This can take a bit more detective work to find the nest and apply a treatment.
  • Signs of an infestation outside may include piles of dirt and sand appearing between pavers and mounds in the lawn. Although this is annoying, it can be helpful in applying a treatment as it shows where they are nesting and therefore where to apply the product.


For much of New Zealand the main pest season for ants are the warmer months, although they can sometimes be a problem in winter, especially if they are nesting indoors. 


  • To get lasting control of an ant problem you will need to kill all the ants in the nest, especially the queen.  If the queen survives, she can start laying eggs again and the ants will return.
  • However, even if you can find the nest, it’s not so easy to kill the queen because
    • Many ant species have more than one queen
    • Many ant species have multiple nest sites as part of the same colony
  • Some of the main pest species, such as the Argentine ant and big-headed ant, are called invasive ants, as they cause problems all around the world. They are very successful in invading and taking over an area. One of the reasons for this success, is their multiple nest / multiple queen colony structure, sometimes allowing the colony to spread to cover many kilometres!
  • Even if you are successful in killing the nest causing the problem, other ants will often move into the vacated territory. This makes controlling ants a continuous battle and the best strategy is a two pronged approach; reducing ant pressure outside and preventing ants from entering the home.


  • Good hygiene is critical;
    • clean away split food and dirty dishes straight away
    • ensure rubbish is put in secure containers
    • don’t leave petfood in bowls on the ground (or if you do, place the bowl in a large bowl of water to create a “moat” which the ants can’t cross)
  • Keep food in sealed containers
  • Seal any small entry holes in the exterior walls / around doors and windows


  • Ants are actually very easy to kill with almost any insecticide. The problem is, if you only spray the ants you see, the chances are there are many more in the nest ready to replace them! And so the ant problem will return. To gain lasting control, you need to spend some time trying to locate entry points into the home and if possible find the nest.  Once you have worked out where the ants are coming from you will probably need to use a number of products to gain control.
  • If you can locate the nest, you will have the best chance of complete control. “Flooding” the nest with insecticide using a ready to use pump pack product will deliver the best results.
  • However, it is not easy to find the nest, and even if you do, often it can be hard to reach. Ant baits are the best way to provide lasting protection as they kill the nest. By applying bait where ants are active, they do they hard work for you, taking the bait (containing a slow acting insecticide) back to the nest, where it is fed to the rest of the colony, leading to its destruction.
  • Insecticide sprays (aerosol or ready to use pump pack) are useful for spraying around entry points and along surfaces where you see the ants trailing. They can also be useful for spraying internal areas which you want to keep clear of ants (such as kitchen cupboards).
  • An insecticide spray around the complete perimeter of the property and entry points is a key part of a control program. Make sure you treat an area 50 cm to 1 m up the wall and the same distance out from the wall across paths and flower beds. Depending on the level of exposure to sun and rain, re-treatment will need to be applied through the year.
  • Treatment between pavers with a liquid insecticide will prevent ants making a mess of your driveway/paths.


  • For outdoor treatments and injection into nests, Pro-Spray Outdoor Perimeter has the 1 m spray wand for safe application and deep penetration into the nest.
  • Pro-Spray Outdoor Perimeter can also be used for larger areas and creating a treated “barrier” around the perimeter of the home and around entry points.
  • For spot treatments and for lasting protection in cupboards the Pro-Spray Crawling aerosol with its extendable nozzle does a great job. It can also be used for spot treatments outdoors
  • Pro-Spray Crawling aerosol is also the best option for direct spray onto ants

For more information on how to control ant infestations and how ant control products work, check out our blog article on “How to control ant infestations”