How to Get Rid of Ants in Perth

What ant species are common in Perth

Coastal brown ants (Pheidole megacephala), also called big-headed ants, are an introduced pest species that form super-colonies: linked networks of nests that share queens, workers and food across hundreds of metres. They generate the most common ant-related call in Perth. Black house ants (Ochetellus glaber) nest indoors and are commonly attracted to sweet liquids and foods in the kitchen, laundry and bathroom. Sugar ants are large, slow and mostly outdoor feeders. Bull ants near bushland have single nests that you can sometimes treat directly.

Dense mass of small brown ants on bare ground — An ant colony on the move. Identify the species before choosing a treatment.

How to tell if you have coastal brown ants

Coastal brown ants are small and light brown to dark brown in colour. Workers are 2 to 3 millimetres long, but the soldiers are larger, 3.5 to 4.5 millimetres, with noticeably bigger heads. You will see two different sizes on the same trail. Look for fine sandy mounds along paving joints, lawn edges and garden beds. The mounds reappear after rain or watering. Trails shift to a new spot every time you spray.

Signs of a super-colony in Perth house types

Coastal brown ants thrive in the sandy soils and paving common in Perth's northern suburbs. They are often seen in lawns and brick paving, excavating large amounts of sand from between cracks. On slab-on-ground homes they form interconnected mounds and fine sandy lines along paving joints. Worst infestations show ants in the kitchen or bathroom after wet weather, following moisture and food sources. Fine sandy mounds reappear after rain or watering.

Why coastal brown ants peak in Perth spring

Coastal brown ants are heaviest along the coastal strip from Hillarys to Mindarie. Spring is when annual top-ups for coastal brown ants become realistic. Heavy colonies excavate so much sand from between paving that bricks become destabilised and may shift. Lawn and plant roots can become too aerated from soil excavation, and plants may show signs of water stress.

Why spraying makes coastal brown ants worse

Repellent sprays, including supermarket ant killers and bifenthrin perimeter sprays, trigger budding: the colony senses the threat and splits into satellite nests to escape. One nest under the patio becomes several across the yard within weeks. This is why homeowners report more ants after treatment. Months of spraying can cause the colony to split and spread. The fix is not more spray. It is a slow-acting non-repellent such as fipronil, or a bait, that workers do not detect and carry back to the queens.

What you can do yourself before calling

Stop spraying first. Repellent spray in the week before treatment scatters the colony. Leave the trails alone. We need to see where they run. Put away pet food, open pet bowls and remove accessible food scraps. Clean up grease from outdoor cooking areas as coastal brown ants prefer fat and protein. Wipe benches indoors. Turn off reticulation the night before a professional treatment so soil treatments are not flushed. For product advice, read the label carefully. The label tells you all you need to know about the product, including usage, mixing and safety instructions. If you're wondering how much pest control costs, itemised quotes are the only fair way to know.

When to call a professional for ant management

Some ants (coastal brown, Argentine, white-footed house) need species-specific chemistry. Guessing the wrong treatment costs time and money. We can identify the species on the first visit and tell you in writing what approach suits your property. Our ant control Perth service involves identifying the species, mapping the trail direction and nest zones, locating entry points into the home, and applying a slow-acting non-repellent or bait at label rate to the outside, with gel bait placed indoors away from food-contact surfaces. Work is carried out by, or under the direct supervision of, a technician holding a WA pest management technician's licence (Health (Pesticides) Regulations 2011). We photograph the map and include it in your report.

What ant management costs in Perth

Typical ranges for a standard three-bedroom home in Perth's northern suburbs are $250 to $400 for an external ant program (identification, non-repellent treatment of nest zones and perimeter, gel indoors and report). A general pest treatment covering cockroaches, spiders and internal ants is $250 to $350. Every job is itemised in writing after we have seen the property. There is no call-out fee and payment is on seven-day terms. See the full investment guide for the detail on what moves a quote up or down.

Frequently asked

Why has spraying made my ant problem worse?

You are probably dealing with a coastal brown ant super-colony. Repellent sprays trigger budding: the colony splits into satellite nests to escape the threat. One nest becomes several within weeks. The fix is a slow-acting non-repellent such as fipronil that workers do not detect, or a bait they carry home to the queens.

What is a coastal brown ant super-colony?

Coastal brown ants form linked networks of nests that share queens, workers and food across hundreds of metres with no aggression between nests. In the northern suburbs they thrive in sandy soil, paving joints and garden-bed edges. You cannot find the nest because there are dozens. This is why spot treatments fail.

How long does ant baiting take to work?

Expect more ants for the first three to seven days as workers recruit nest-mates to the bait. That is the bait working. Activity drops sharply by the second week. Full collapse of a super-colony typically takes four to six weeks. Small, localised colonies clear in one to two weeks.

Can you treat ants in the kitchen?

Yes. Indoors we use gel bait placed inside cabinetry, behind appliances and along the hinge side of kickboards, away from food-contact surfaces. Gel baits containing thiamethoxam or indoxacarb are effective. We do not spray kitchen interiors with a residual for ants; this keeps product off benches and food handling areas.

What about kids and pets during an ant treatment?

Gel placements go where fingers and paws do not reach. External non-repellent treatment is applied to soil, paving joints and nest zones at label rate. Kids and pets stay off treated areas until the re-entry period we advise has passed, usually once surfaces are dry. We give you this in writing on the treatment report.

Will the ants come back after treatment?

Coastal brown ants re-invade from neighbouring properties, so pressure never drops to zero on the coast. Our external ant program carries a three-month re-treatment promise (terms at djpest.com.au/warranty) on the treated zones. For properties with chronic pressure, an annual spring top-up is realistic. We tell you this rather than sell a quarterly plan.

How do I know if the treatment is working?

Within the first week you may see more ants as baits recruit workers. By the second week activity should drop noticeably. After the second week, activity should continue to decline. If active trails remain in the treated zones after three months, call us and we return at no charge. Our external ant treatment carries a three-month re-treatment period (terms at djpest.com.au/warranty).

What is the difference between black house ants and coastal brown ants?

Black house ants (Ochetellus glaber) are 2.5 to 3 millimetres long, intensely black, and commonly attracted to sweet liquids and foods indoors. They naturally nest indoors in roof and wall spaces, rolled up awnings and pots. Coastal brown ants need a slow-acting non-repellent or bait outdoors to break the super-colony.

Sources

Text your suburb and what you're seeing to 0468 170 107 for a written price.

Ant Control Perth, the full service and the investment
Every guide on ants
Pest management investment ranges in Perth, every service with a typical range
What's my pest?, pick what you saw
All pest guides