Correct identification changes everything. The bait that controls one ant species can cause another to bud into several colonies; the treatment for a German cockroach is not the treatment for an Australian one. This guide covers the pests most commonly found in Australian homes and commercial sites.
Cockroaches
The species matters enormously. German cockroaches are small, tan, with two dark stripes behind the head. They live indoors permanently, breed rapidly, and concentrate in warm humid voids — behind fridges, dishwashers, motors and kitchen cabinetry. They are the species behind most serious commercial infestations and are controlled primarily with gel baits, not sprays.
Larger species such as the American and Australian cockroach typically live outdoors, in drains, subfloors, roof voids and garden beds, and wander inside. Control focuses on the harbourage and entry points rather than the interior.
Signs: Droppings resembling ground pepper, a musty odour, egg cases (oothecae) glued into corners, live insects when a light is switched on at night.
Risk: Contamination of food surfaces; cockroach allergens are a recognised asthma trigger.
Rodents — rats and mice
Roof rats climb and nest high — roof voids, wall cavities, trees against the building. Norway rats burrow low, favouring drains, subfloors and compost. House mice need very little: a gap the width of a pencil and a crumb supply will do.
Rodents gnaw constantly because their incisors never stop growing, which is why they are a genuine fire risk once they reach wiring. Control combines secured bait stations, snap traps where baiting is unsuitable, and — critically — proofing.
Signs: Droppings, gnaw marks, greasy rub marks along skirting and beams, scratching in the ceiling at night, shredded nesting material.
Proofing: Door brush strips, sealing service penetrations, mesh over vents, trimming branches away from the roofline.
Ants
Ants indoors are usually foraging for sugar, protein or moisture. Spraying a trail kills the visible workers and achieves very little — the colony continues producing more. Baiting works because foragers carry the active ingredient back to the nest.
Some species respond badly to repellent sprays by budding: the colony splits and relocates, turning one problem into several. This is why identification and bait selection matter more than spray volume.
Termites (white ants)
Termites are in a category of their own because they cause structural damage that is not covered by ordinary pest treatments or, generally, by home insurance. They work silently inside timber and are frequently discovered only when a surface is tapped or a skirting gives way.
Australian Standard AS 3660 covers protection of buildings from subterranean termites, and AS 4349.3 covers timber pest inspections. A general pest treatment is not a termite treatment and does not inspect for them — these are separate services.
Signs: Mud tubes on foundations or piers, hollow-sounding or blistered timber, tight-fitting doors, discarded wings near windows after a flight.
Recommendation: A timber pest inspection at least every twelve months, and more often in high-risk areas.
Bed bugs
Bed bugs are hitchhikers, not a sign of poor hygiene. They arrive in luggage, second-hand furniture and bedding, then hide in mattress seams, bed frames, bedheads and skirting within a few metres of where people sleep.
Treatment is meticulous and usually staged: a thorough inspection, targeted treatment of all harbourage, laundering of fabrics at high temperature, and a follow-up visit to catch newly hatched nymphs. Eggs resist most treatments, which is why one visit is rarely enough.
Signs: Rows of bites, small dark faecal spotting on the mattress or bedhead, shed skins, blood spotting on sheets.
Fleas
Fleas are usually noticed after a pet has been present, or when someone enters a vacant property and the vibration triggers dormant pupae to hatch en masse. The adults you see are a small share of the population — most of it is eggs, larvae and pupae in carpet, bedding and subfloor.
Pupae are heavily protected and survive most treatments, so activity commonly continues for one to two weeks. Vacuuming frequently during that period is genuinely useful: it removes eggs and larvae and stimulates remaining pupae to emerge into the treated surface.
Wasps and bees
Wasps become aggressive when a nest is disturbed and can sting repeatedly, which makes DIY removal of an established nest a poor idea — particularly at height or near an entrance where people pass.
Bees are treated differently. Honey bees are valuable pollinators and, where a swarm or hive can be safely accessed, relocation by a beekeeper is preferred over destruction. An abandoned hive left inside a wall cavity should always be removed, as residual wax and honey attract other pests.
Spiders
Most spiders are harmless and genuinely useful, eating other insects. The concern in Australia is the small number of medically significant species — funnel-webs in parts of the east, redbacks nationwide in dry sheltered spots such as under outdoor furniture, in sheds and around meter boxes.
Control usually means a residual treatment to external harbourage, webbing removal, and reducing clutter and debris around the building. Reducing the insects spiders feed on reduces the spiders.
Flies
Flies are a breeding-source problem. Adults are easy to kill and immediately replaced unless the source is found — a bin store, floor waste, drain build-up, a dead animal in a cavity, or organic matter under equipment.
In food premises, control combines source elimination, fly control units positioned away from food preparation and open doorways, and door seals or air curtains. Fly units need their tubes replaced periodically or they stop attracting insects while still appearing to work.
Birds
Pigeons and starlings roosting on a building create more than mess. Droppings are corrosive to paint and metalwork, create a genuine slip hazard, and harbour mites and pathogens that persist after the birds leave.
Management is physical rather than chemical: netting to close off roosting areas, spikes on ledges, and proofing of gaps in eaves and roof spaces, followed by thorough cleaning and decontamination of fouled areas.
Possums
Possums in a roof are unmistakable — heavy thumping and scratching after dusk, rather than the light scurrying of rodents. They are a protected native species in Australia and must be handled in accordance with state wildlife regulations, which restrict how and where a captured animal may be released.
The durable solution is exclusion, not removal alone. Once the animal is out, the entry point must be sealed and an alternative such as a possum box provided nearby — otherwise another possum simply takes over the vacated space.