Five main types of pest ants in the Perth area.

Five main types of pest ants in the Perth area.

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There are five main types of invasive ants in the Perth metro area.

Pheidole megacephala Coastal brown/big headed ants
Technomyrmex White footed ants
Linepethina species Argentine ants
Iridomyrmex spp (various) Odorous ants
Ochotellus spp Black house ants

Identify your ant species.

Firstly you must identify which Genus and possibly species of ant you have.
Identify the type of ant by its looks, food preferences, behaviours, nesting and what potential problems it is causing.
You can use DNA testing but that is expensive and in most cases they can be id’d by looking with an eyeglass or microscope. Close up examination using keys to identify needs some skills and correct information.

Easiest identification is by observing behaviours etc (above):
*Food preferences: some ants like only sweet foods, some prefer oily foods such as vegetable oil, peanut butter or animal fats.
*Trailing behaviour. Some ants make obvious trails and walk quickly while others meander and seem less orderly.
*Sting or bite? Some ants will do one or the other, others can do both.
*Habitat/nesting type. White footed ants, for instance, will live inside buildings whereas most other ants prefer to live outdoors, only coming in if there is easy access to preferred foods.
*Smell when squashed. Some ants smell more or less strongly of formic acid when squashed and some ants don’t smell at all.
*Do they dominate other ants and displace them?

As with any pest problem always use PHYSICAL or CULTURAL CONTROL first, then LEAST TOXIC solutions and highly TARGETED baiting.
This includes removing food sources, keeping benches clean where ants are indoors and finding gaps and sealing them to prevent incursion of the tiny insects. If it just a small outbreak then peppermint oil and other non-toxic efforts may work, but in some areas, these small resilient animals can cause issues in the home and garden. Pouring boiling soapy water into their nest can be useful. Again, though. If the entire neighborhood is infested and there are multiple queens, then a proper treatment may be needed.

Big headed ants/coastal brown
Pheidole megacephala
These ants are very common around Fremantle. Easily identified by looking to see whether about 10% have large heads compared to the rest of the population of ants present. They have no smell or sting but they can cause a not-very-painful bite. They tunnel under pavers, leaving piles of sand everywhere.
They move into pots and damage plants by eating the root hairs which are high in proteins and sugars. They will also farm aphids and scale for honeydew.They will swarm at foods.
Borax bait using a plain peanut butter and vegetable oil base can be used. A highly succesful target specific product called Amdro works really well.

White footed ants
Technomyrmex
Smell when crushed and form trails. They don’t sting.
They will live inside buildings and can appear suddenly in large numbers and then be gone again just as quick.
They will live on sites with other ants species and don’t dominate.
These can be difficult to control, needing special baiting repeated frequently as they do not pass poisons to the higher orders but keep it to themselves and make clean sterile eggs for the queen. This means only soldiers die with baiting and thus it needs repetition until the nest is depleted.

Argentine ants
Linepethina humile
Argentine ants are about 2-3 mm long and smell slightly of formic acid when crushed. They have no sting and tend to create regular trails, which they move along slow or fast. They usually live outside and can form super colonies which displace other ants species.
These ants eat sugars and proteins, however sugary secretions called honeydew from scale on plants are a favourite, thus the ants will sometimes ‘farm’ scale insects.
These ants have multiple queens in each nest and new colonies are created when a queen and some workers move to a new area. Their nests are not always easy to identify for baiting. Least toxic control is by winter trapping of queens. Garden hygiene, removing piles of leaves, sticks etc, can provide less habitable spots for them. Other wise persistence is needed to control this hard to exterminate pest species.

Odorous ants
Iridomyrmex spp
This Genus of ants often move in after coastal browns are removed. They have a strong smell when crushed and no sting. They run riot when disturbed, running all over the creature disturbing their nest. These ants live outside in big colonies and will displace other species.
They prefer animal fats and sugar. Control is by use of targeted baits and DIY options – 2% borax dissolved in 25% honey or sugar + 73% H2O. Place baits where there are large numbers of ants during their frenzy.
Ant rid and other target specific ant baits are available in some hardware or pet stores.

Black house ant
Ochotellus spp
Sometimes outside but mostly inside, the black house ants only have a slight smell and are timid, they are easily discouraged by wiping surfaces with eucalyptus oil. They have no sting.
These ants prefer sugar, and can be controlled using Ant-rid.

If you still don’t know what sort of ant you have you could use this service:
Identification service – Department of Agriculture and Food
Correct identification of the pest ant is crucial before commencing any control procedures. There are pest ants that can be more easily controlled based on advice appropriate to that species. A free identification and advisory service is provided by the Department of Agriculture and Food. To submit specimens for identification, stick about a dozen ants to a piece of paper with clear tape and enter your contact details on the paper. Ensure the ants are collected from a clean surface. This will prevent picking up sand and other debris which can allow the ants to escape from under the sticky tape, or spray the ants first with fly spray.

Specimen identification requirements
When sending or delivering samples, the following information is required:
• Collector’s name, location (where the specimen was found), full address, telephone number and e-mail address, description of the damage and date collected.
Department of Agriculture and Food
Pest and Disease Information Service
3 Baron Hay Court, South Perth WA 6151 Freecall: 1800 084 881
Email: info@agric.wa.gov.au

Once you know what you have but still don’t know how to control the pest at hand contact Systems Pest Management, Fremantle for advice on the least toxic way to control your pest ants.

David Piggott from Systems Pest Management promotes and uses non toxic solutions for termites and ants and willingly shared the information that I used to start these notes.

Some other resources ..
archive.agric.wa.gov.au/objtwr/imported_assets/…/gn_argentine_ants.pdf
http://argentineants.landcareresearch.co.nz/identification.asp
msucares.com/pubs/publications/p2407.pdf

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