Threats
+The impact of Argentine ants extends far beyond being a household nuisance. They are recognised globally by the International Union for Conservation of Nature (IUCN) as one of the 100 worst invasive species due to their ability to alter ecosystems and outcompete native wildlife.
1. Ecological Threats
Argentine ants aggressively displace native ant populations, especially species that are crucial for pollination and seed dispersal. For instance, native ants that transport seeds for the regeneration of Australian flora are often driven out, reducing plant diversity over time.
They also affect small reptiles, frogs, and birds that depend on native ants as a primary food source. In coastal regions of Victoria and South Australia, the spread of Argentine ants has been associated with declining populations of native ant-eating lizards such as the coastal horned dragon and skinks.
Argentine ants form dense, competitive populations that dominate local food resources, changing soil microhabitats and disrupting the natural balance of the environment.
2. Agricultural Threats
In agricultural settings, Argentine ants pose a serious economic and ecological risk. They tend and protect sap-feeding pests like aphids, mealybugs, and scale insects, which feed on crops and excrete honeydew — a sugary liquid that the ants collect as food. By protecting these pests from natural predators, Argentine ants indirectly contribute to crop damage and reduced yields in orchards, vineyards, and nurseries.
Their activity can also increase the spread of sooty mould, a fungal growth that thrives on honeydew deposits and interferes with plant photosynthesis. This has been observed in citrus, grape, and stone fruit plantations in southern Australia.
3. Domestic and Structural Threats
In urban areas, Argentine ants invade homes and commercial properties during hot or dry weather, or after heavy rain. They are attracted to moisture and food sources, particularly sugary or oily substances. Large trails may be seen along kitchen benches, sinks, and bathrooms.
While they don’t cause structural damage like termites, their infestations are persistent and unhygienic, contaminating food and surfaces. They can also interfere with electrical systems by nesting in switchboards or appliances, though such cases are less common.
Preventions
+Effective management of Argentine ants requires a long-term, integrated approach. Because their colonies have multiple queens and satellite nests, standard insecticide sprays often fail to reach the entire colony and can even worsen the problem by causing colonies to split and spread further.
1. Environmental and Structural Prevention
- Seal Entry Points: Fill cracks, crevices, and gaps around windows, doors, pipes, and foundations
- Reduce Moisture: Fix leaking taps, drainage issues, and irrigation leaks that create damp nesting spots
- Manage Vegetations: Trim trees and shrubs that touch walls or roofs, as they serve as bridges for ants.
- Eliminate Nesting Areas: Remove garden debris, mulch piles, and rocks near structures.
- Maintain Waste Hygiene: Keep outdoor bins tightly closed and empty them regularly to prevent odours.
2. Food and Sanitation Control
- Store food, especially sugary or oily items, in airtight containers.
- Wipe up spills immediately and maintain clean kitchen surfaces.
- Avoid leaving pet food outside or overnight.
- Clean drains and compost areas frequently to remove organic residues.
3. Chemical and Baiting Methods
The most effective control method for Argentine ants is baiting, not surface spraying. Baits contain low-dose insecticides mixed with attractive food substances, encouraging workers to feed and carry them back to the nest. Over several days, the active ingredient spreads through the colony and eventually eliminates the queens.
In Victoria, registered pest-control professionals use products such as borate-based baits or fipronil formulations, approved under Australian Pesticides and Veterinary Medicines Authority (APVMA) standards. These are applied strategically to ensure safety for humans, pets, and beneficial insects.
Follow-up monitoring is essential. Even after successful treatment, re-infestation can occur from nearby colonies if preventive measures are not maintained.
Summary
+Argentine ants are among the most persistent invasive species found in Australia today. Their cooperative colony structure, adaptability, and association with other pests make them difficult to manage without targeted, scientific approaches.
For long-term control, prevention is key — maintaining hygiene, blocking entry points, and using professional-grade baiting systems remain the most reliable strategies.
At Gill Pestworks, we advocate for informed pest management. Understanding the habits, risks, and control methods of Argentine ants helps protect not only homes and businesses but also Australia’s native ecosystems.
