Are ants the problem in your garden?

Ants have become more of a problem in Perth when water restrictions came into play.

This is because ants don’t generally like to get wet feet!. When we watered everyday the soil remained wet and there was less chance of it becoming hydrophobic (anti wetting). Hydrophobic soil is the first step towards having a sparse and weak lawn sward as the turf does not get the water it needs to survive. Ants then move into these de generated lawn areas and build their nests.

The first step to getting rid of ants is to make the environment less attractive to building their nests by using a commercial grade wetting agent on your lawn and gardens. You then need to do a retic audit to ensure you are putting on enough water. Again, the wetting agent will not create water, it will just make sure that the water you are applying gets into the soil. For more help on hydrophobic soils and dry patch click here.

Now that you have got the water right you need to apply a fertilizer to encourage the grass to grow back into the dry patches that the ants have built their nests in.

Increasing the health and vigour of your turf will make the environment less attractive for ant nests. If you do not tackle the problem holistically the problem will continue after you have applied your contact spray as they will just move back in when the spray has worn off.

Most insecticides for ants are  broad-spectrum chemicals, meaning they kill indiscriminately; as well as the intended pests. They can harm beneficial insects, including honey bees, as well as cats and aquatic life.

Understanding the Terminology

Insecticides for ants are often the same that are used for termites. There is different terminology around pesticides and how they work including contact, residual, systemic and baits. These terminologies are explained below.

Contact Only

Contact only products kill what the spray or granules come into contact with. This mainly includes products that have a very low amount of the active ingredient. These are often sold in shaker packs and are very economical. Products include Bifenthrin at 2gm per kg and permethrin Ant Dust.

Residual Insecticides

Residual insecticides means they last longer in the soil and on hard surfaces. Spraying can be used to form a perimeter barrier treatment that ants don’t like to cross, effectively keeping ants outside the premises. Products include Coopex, Bifenthrin, Insectigone and Ficam. Bifenthrin has the longest residual effects in the soil, however, while safe for dogs and humans, cats and fish are affected.


Systemic is when a plant that is sprayed takes up the chemical into its system and the insect ingests the chemical when it eats the plant. When systemic pesticides are applied to the soil, beneficial insects, birds and even pets and people are much less likely to encounter the pesticide in the form of residues or spray drift. An example is Imidacloprid. Imidacloprid, while very safe for mammals, is very dangerous to bees, so should not be used where bees are expected to be gathering their nectar. Fipronil is another systemic insecticide used for targeting ants. Systemic insecticides are effective as sap carries the most concentrated amount of chemical.


Baits are when the chemical is taken back to the nest and the queen is affected, they are not all residual. This means that while effective at killing that particular nest, they will not prevent another colony from starting up as soon as the original queen has been killed off. And nature hates a vacuum, another colony will start-up in this space.

Amdro is an example of a Bait that is effective for Coastal Brown Ant.

Reading the active ingredients

It is important to learn to read the active constituents on the insecticide labels. Many brands have different names for what is the same Active (and this same active will be relabeled to target other insects). It is also important to know that not all active constituents control all ant varieties. This is why you must identify which ant species you are targeting.

The most common ingredients in ant killers


Fipronil is systemic and residual. It is the major active of Frontline for cats and dogs, so won’t harm cats and the main active in Termidor and in Bait Gels. It is toxic to fish and non target insects such as bees and should not be applied to crops where bees are foraging. Fipronil works when the ant comes into contact with the chemical affecting the insects nervous system, it is also residual. Fipronil is not dangerous to humans or pets, making it a good choice around the home. Access to the area sprayed should be restricted until the surface has dried.


Deltamethrin  is residual and can be used indoors. Once dry, the spray leaves an invisible film that repels ants so they won’t enter the house. This means, like bifenthrin and permethrin) it does not act as a bait, as the ant does not walk through it and take the chemical back to the nest like a non repellent insecticide. Deltamethrin is popular due to its low rates, making it non toxic for inside the home. This chemical is very popular in restaurants as it also controls spiders and flies. The odorless solution is water safe and can be sprayed on carpets, upholstery, rugs, wood floors, tile floors and other types of flooring or fabrics that are not harmed by water.


Bifenthrin belongs to the  family of insecticides know as pyrethroids. Other ant killers in this family include Deltamethrin and Permethrin. All of these pyrethroids are contact insecticides with residual properties. They are also toxic to cats, however very safe with dogs and humans when used as per label. Bifenthrin has the longest known active residual affect in soil, although like all pyrethroids, when sold in the low doses, as in most hardware stores, the residual affect is non-existent. It is also not very effective as a contact killer in these low doses. In doses of 100g per litre, Bifenthrin is a common choice of professional pest companies.


Permethrin, like bifenthrin and deltamethrin, is a contact insecticide with residual properties. This means the ant needs to come into direct contact with the insecticide to be controlled. As they hang around for a while they are also residual.  While permethrin may be marketed as an insect repellent (barrier control), it doesn’t prevent insects from landing. Instead it works by incapacitating or killing insects. While being mild in toxins, it is still highly toxic to bees and aquatic life. This chemical is also common in flea control, although like bifenthrin, it is not safe for cats.


Imidacloprid is a contact insecticide with residual properties. It was the most widely used systemic insecticide for ants and termites however it is very toxic to bees.  Imidacloprid was popular because being systemic it was absorbed by the plant, meaning there was not much residue left on the surface. This, and the fact mammals have a very different central nervous system to insects, made it very safe for farmers who deal with insecticides in high volumes. As ants are sap sucking insects, systemic insecticides are very effective. Sap holds the highest concentration of the chemical in the plant. Like all insecticides that are non targeted, it should not be used where bees are foraging.

Types of Ants in Perth

Black ``Sugar`` Ants


Black House ants are a native of Australia and they are commonly attracted to sweet liquids and foods and are often drawn to the kitchen, laundry and bathroom. They naturally nest and forage in trees, feeding on insects, honeydew and nectar. They do not cause the damage that the Brown Coastal ant does however can still be annoying.

What To Use

For inside you can spray Permethrin and Deltamethrin. For outside, Bifenthrin and Fipronil is a good choice. In the past the most effective product was Clorfuifous for these little ants, however it’s label has now been changed to “not for household use”, so we can no longer recommend this product to householders.

Vista 200sc


Fipronil is effective on various pests, including ants, molecrickets and stem weevil. Fipronil is used in flea control products and on crops including turf

Brown Coastal Ant


Originally an African native, the Coastal Brown Ant is very difficult to control.  Multiple queens create enormous, interconnected supercolonies which can extend over many hectares. Often seen in lawns and in brick paving,, these ants are the culprits for moving your sand around. They will disrupt paving and make holes in your lawns. Roots of lawn and plants can become exposed and suffer water stress. If present in high numbers, they may enter the home to forage for fat and protein rich food.

What To Use

Hydramethylnon is very effective at eliminating these ants. Amdro is a popular brand name of this chemical. Hydramethylnon will not control Black “sugar” ants.



Amdro is a selective insecticide for control of certain ant species. Here is Perth the targeted species is Coastal Brown Ant

Singapore Ant

Singapore Ant

Singapore ants are another introduced species. They are a small light gold to light brown ant with a long slim body. They are mainly a pest in north Western Australia. However, during summer, these ants have caused problems in the Perth area. These ants live happily with humans and do come inside.

What to Use

Singapore ants can also be controlled with Hydramethylnon, so Amdro is the best choice for these ants.



Amdro is a selective insecticide for control of certain ant species. Here is Perth the targeted species is Coastal Brown Ant

Bull Ants

Bull Ant

Bull ants are also known as Seargent Ants and Inch ants. They do not cause much damage but can give a nasty sting. They are found in natural and urban areas and have a large mounded nest.

What to Use

Can be treated with Bifenthrin or Fipronil aimed at the nest site.

Argentine Ants

Argentine Ants

Another introduced species, Argentine ants are small, slender and brown and are a large pest in Perth, often entering houses in search of food. Their habit is to follow continuous well-defined trails, sometimes more than three ants wide. 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. They are significant pests to the natural eco system and are difficult to eradicate. Eradication involves repetitive applications of contact and residual insecticides.

Argentine ants remain the most difficult common pest ant in WA to control. Once cleared from an area, argentine ants can quickly re-colonise it from untreated neighbouring properties. This can occur within two weeks.

What to Use

Barrier treatment with bifenthrin, permethrin of fipronil is usually the best solution. A second treatment will be necessary 2 to 4 weeks after initial application. Chlorpyrifos was very effective in the past because of its low repellence, meaning the ants did not notice the insecticide and would walk it back to the nest on the feet and bodies.

Natural Remedies - Borax

When ants eat the borax bait, it interferes with their digestive system and eventually kills them. However, it’s not an immediate death. That’s because, for effective ant control, you need to eliminate the queen and the rest of the colony. Worker ants will consume the borax bait and bring it back to the colony for the other ants to eat.

Ants will not eat Borax on its own, you must mix it with their favourite food. A popular recipe for WA is half cup of sugar, 1.5 tablespoons of borax, and 1.5 cups of warm water. Simply mix all the ingredients together until they’re blended, and place the bait in the container

Holistic Remedies

Don’t forget, it is not the ant that is the problem if your plants die. They are not the cause they are just the indicator. Your plants and lawn are dying from lack of water either in the soil or the potting mix. If the pots and lawn had enough water the ants wouldn’t move in. Improve the health of your lawn with proper fertilising, mowing and watering practices, and your ants will be less of a problem.



Borax is also know as boron and sodium borate and is a naturally occurring mineral. It is used to eradicate ants and for use in household cleaning.

CompelOut of stock



Compel Bifenthrin is a broad spectrum insecticide containing 100g/L of the active constituent Bifenthrin. It is registered for control of lawn grubs and ants in turf.

Imidacloprid 200


Imidacloprid is a systemic insecticide widely used to control pests in gardens and turf. It is also for the treatment of fleas in pets