Termite swarmer
Termites have a broad waist, straight antennae and two pairs of equal-length wings; ants have a pinched waist and elbowed antennae.
ANT IDENTIFICATION
Citronella / Yellow Ants
Lasius interjectus / Lasius claviger group
Citronella ants are yellow to yellow-brown subterranean ants that release a lemon or citronella-like odour when crushed. Workers are seldom seen indoors, but winged swarmers may suddenly appear from foundation cracks, slab joints or wall openings and are commonly mistaken for termites.
QUICK FACTS
Identification at a glance
GenusLasius
Worker colourYellow to yellow-brown
Distinctive clueLemon/citronella odour when crushed
Nest typeSubterranean
FoodHoneydew from root-feeding insects
Main issueNuisance swarms; termite confusion
OVERVIEW
What property owners should know
Citronella ants spend most of their lives underground, where colonies tend root-feeding aphids and mealybugs and collect the sweet honeydew they produce.
Because workers rarely forage openly through kitchens, a colony can remain unnoticed until winged reproductive ants emerge in a sudden swarm. Swarms from cracks near slabs or foundation walls are visually dramatic and are often reported as termites.
The ants are nuisance pests rather than wood-destroying insects. They do not eat structural lumber or masonry, but recurring swarms can justify locating the nest and checking the surrounding moisture and soil conditions.
IDENTIFICATION
What to look for
01
Workers are yellow to yellow-brown and relatively small
02
Winged swarmers can be darker and substantially larger than workers
03
Crushed ants release a noticeable citrus or citronella-like smell
04
Like other ants, swarmers have elbowed antennae and a narrowed waist
LIFE CYCLE & BIOLOGY
How the population develops
Colonies live underground and maintain a close association with root-feeding insects that produce honeydew.
Winged reproductives may emerge in warm seasons, but indoor swarms can occur at unusual times where soil beneath heated structures remains warm.
A swarm is temporary; the workers generally remain underground rather than establishing trails through household food.
HABITAT & HARBOURAGE
Where activity develops
- Soil beside foundations
- Beneath concrete slabs and patio stones
- Under rocks and logs
- Lawns, gardens and open wooded areas
- Rotting wood in contact with soil
Seasonality
Swarming is often reported in warmer months, but heated structures can shift timing and produce spring or fall indoor swarms.
VISIBLE EVIDENCE
Signs worth documenting
One clue rarely tells the whole story. The pattern, location and freshness of evidence help determine whether activity is current and where it is centred.
Yellow ants or dark winged ants emerging from a crack
Citronella-like odour when specimens are crushed
Small soil mounds near foundation openings
Repeated seasonal swarm from the same slab or wall area
WHY IT MATTERS
Health, property and operational concerns
- Alarm from confusion with termites
- Recurring nuisance swarms indoors
- Colonies close to foundations or under slabs
- Unnecessary pesticide use when misidentified
LOOK-ALIKES
Common identification mistakes
Pharaoh ant
Pharaoh ants are tiny indoor foraging ants that form visible food trails; citronella-ant workers are usually subterranean.
Field ant
Field ants are generally more visible outdoors and do not have the characteristic citronella odour.
INSPECTION
How we narrow down the source
A useful pest inspection connects the insect or rodent to harbourage, entry, food, moisture and building conditions.
01
Collect a specimen from the swarm for identification
02
Check antennae, waist and wing proportions before calling it a termite
03
Look for soil mounds or emergence gaps near the foundation
04
Inspect slab cracks and door thresholds where swarmers appeared
05
Note whether ordinary workers are actually foraging indoors
PREVENTION
Reduce the conditions supporting activity
Seal practical slab and foundation cracks after activity is understood
Correct chronic moisture beside foundations
Avoid unnecessary food-bait programs when no indoor foraging trail exists
Maintain exterior grading and drainage
Confirm repeated swarms professionally before treatment
PROFESSIONAL CONTROL
What a thorough service plan should address
Product use is only one part of structural pest management. Identification, placement, sanitation, exclusion and follow-up determine whether the result lasts.
01
Distinguish citronella ants from termites first.
02
Locate likely subterranean nesting or emergence zones.
03
Treat the colony only when nuisance or repeated indoor swarming justifies intervention and the product label supports the site.
04
Explain that the ants are not consuming the structure so the customer understands the risk accurately.
FAQ
Detailed questions property owners ask
Why do citronella ants smell like lemon?
They release a citrus-like odour when threatened or crushed, which is the feature that gives them their common name.
Are citronella ants termites?
No. Winged ants can look similar at a glance, but ants have elbowed antennae and a narrow waist. Termites have straight antennae and a broad waist.
Do they eat wood?
No. They may nest near rotting wood or foundations, but they are not wood-destroying insects.
Why do I only see them when they swarm?
Workers spend most of their time underground tending root-feeding insects. The winged reproductive stage is often the first part of the colony a homeowner notices.
Should I spray every yellow ant I see?
Not before identification. Small yellow ants can include species with very different biology, and some indoor ant problems respond poorly to indiscriminate spraying.
Can they nest under a concrete slab?
Yes. Extension references describe colonies beneath slabs, patio blocks and near foundation walls.
REFERENCE SOURCES
Where this information comes from
These pages are written by Emerald Pest Control from authoritative pest, public-health and extension references. They are not copied from competitor websites.
LOCAL PEST HELP
Need help with citronella / yellow ants?
Send us a photo or request an inspection. We can confirm the pest, identify the conditions supporting activity and explain the appropriate next step for your property.