John Stewart, Technical Training Manager at Pelsis Ltd, shares tips for best practice ant control.
Ants are among the most common pest challenges facing professionals in Australia and New Zealand. Whether invading homes, commercial kitchens, or food-processing facilities, these social insects can quickly frustrate clients and challenge even the most experienced technicians.
Behind every trail of ants is a sophisticated colony driven by hierarchy, communication, and survival. Understanding this biology – and applying control strategies that align with it – is what separates quick fixes from long-term success.
This article details key insights from Pelsis’ Ants on the Trail technical webinar, exploring how pest managers can apply behaviour-based control strategies to achieve reliable, sustainable results across Australasia.
Understanding ant biology and behaviour
At the core of every effective ant management program is a solid understanding of how ants live, move, and communicate.
Ants operate as superorganisms i.e. colonies functioning as a single unit. They rely on pheromone trails to recruit nestmates to food sources, form new nests, and defend territory. Breaking or manipulating these chemical communications is often the most powerful lever a pest manager can pull.
Several key biological factors must be considered before any control program is established.
Colony structure
Some species are monogyne (single queen), while others are polygyne (multiple queens). Multi-queen colonies can split, relocate, and re-establish quickly – a major reason why incomplete treatments often fail.
Foraging behaviour
Foragers represent only a small fraction of the total colony, yet they are the link between the environment and the nest. Targeting these workers with slow-acting baits can ensure toxicants reach queens and brood.
Colony relocation
Disturbing nests with strong repellents can cause ‘budding’, where parts of the colony relocate and form new nests, multiplying the problem.
Environmental triggers
Temperature, humidity, and resource availability heavily influence foraging activity. In Australia and New Zealand, hot summers and high humidity accelerate ant metabolism, often increasing trail intensity and bait uptake.
While the research I undertook for the Ants on the Trail technical webinar covered global trends, certain ant species dominate the Australasian region and require specific approaches.
Argentine ant (Linepithema humile)
A major invasive species known for massive colony networks and switching between sweet and protein based foraging.
Black house ant (Ochetellus glaber)
Common in domestic settings; trails along edges, skirting boards, and benchtops.
Coastal brown ant (Pheidole megacephala)
Aggressive and often forms multiple nests; protein and sugar feeders.
White-footed house ant (Technomyrmex albipes)
Prefers moist environments and can form large supercolonies. For unknown reasons the ants are attracted to electrical contacts. Electrocuted corpses build up, insulating the contacts and leading to switch failure.
Native Iridomyrmex species
Often beneficial but can become nuisance pests near structures or during dry periods.
Understanding which species you’re dealing with is essential, as bait preference, foraging times, and nesting sites differ dramatically.
Inspection and assessment: reading the trail
A thorough inspection remains the cornerstone of professional pest control. I like to say that ants will tell you what’s happening if you’re patient enough to watch. A number of steps need to be taken during the initial inspection.
Locate trails
Identify active foraging routes during peak activity (typically warmer parts of the day).
Follow the flow
Trace trails back to possible nesting sites i.e. soil, wall cavities, foundations, garden edges, or roof voids.
Identify food sources
Ants target sweet residues, proteins, and fats; eliminate these attractants to aid control.
Check environmental conditions
Moisture, mulch, and vegetation touching structures are key contributors to infestations.
Record everything
Mapping trail activity over multiple days gives valuable insight into colony behaviour and bait placement strategy.
There’s no single ‘silver bullet’ when it comes to ant management. Success depends on integration i.e. using baits, residual products, and environmental correction together in a way that aligns with the colony’s biology.
Baiting
Baiting requires a slow and steady approach. Always use slow-acting toxicants; quick-kill sprays may eliminate foragers but won’t reach the queens. Also, ants’ dietary needs shift seasonally – sugars when energy is required, proteins for brood rearing. Both options should be offered during the initial control phase.
Position baits directly on foraging trails or near nesting areas, protected from rain and sun exposure. These baits must be kept available until activity ceases completely; prematurely removing bait can interrupt colony elimination.
Residual treatments
Residual insecticides are best used as supplementary tools, not the first line of attack for colony elimination.
Apply targeted treatments into cracks, crevices, and voids where foraging ants travel. Also target potential entry points such as window frames and expansion joints. Treatments should only be applied to nest sites when the colony is confirmed and accessible. In all cases, avoid broad-surface treatments that repel ants or fragment colonies. Figure 1 provides some helpful tips for quick wins in the field.
Environmental and non-chemical measures
Environmental controls can contribute significantly to the success of an ant control program. Sanitation measures to reduce potential food sources is an important one, both in domestic and commercial situations. In commercial environments this will likely mean educating and training staff.
Access points such as cracks, gaps, and weep holes should be filled and vegetation and mulch moved away from structural contact points. Moisture is important for ant survival, so customers should be advised to repair leaks, improve drainage, and reduce condensation zones to reduce conducive conditions.
Australasia’s diverse climate adds layers of complexity to ant control. In Australia, high heat accelerates foraging and colony growth. In tropical and subtropical regions, ants can remain active year-round, necessitating ongoing monitoring. Meanwhile in New Zealand, cooler seasons reduce surface activity, but indoor infestations often persist due to controlled environments in homes and commercial spaces.
Whichever species is being targeted, some common mistakes are best avoided, such as those listed below.
Using fast-knockdown sprays on trails
This kills visible ants but alerts the colony and triggers relocation.
Ignoring identification
Misidentifying species leads to wrong bait choice and wasted effort.
Incomplete servicing
Treating once and walking away invites reinfestation.
Overlooking moisture sources
Ants thrive where humidity remains unchecked.
Failure to communicate with clients
Educating property owners on sanitation and exclusion is vital for sustained control.
Effective ant management isn’t about eradication – it’s about understanding. By recognising the biological and behavioural drivers behind infestations, pest professionals can design programs that align with how ants actually function.
I believe that when you think like an ant, you can outsmart the colony. For pest managers across Australia and New Zealand, that mindset – paired with methodical inspection, precise baiting, and disciplined follow-up – is the foundation of reliable, professional control.
Header image of Argentine ant (photo credit: Lachlan Copeland/iNaturalist)
