This native ant is quickly becoming one of the most dominant ant species in North America.
Why are odorous house ants a problem?
Odorous house ant colonies can be huge, comprising many nests over a large area. When they find food, the ants can enter homes and businesses by the thousands, marching in well-defined trails. Using the wrong DIY or do-it-yourself ant killer makes odorous house ants more difficult to eliminate.
What do odorous house ants look like?
Odorous house ants are uniform in shape and colour. Key characteristics:
- Size: 2.4 to 3.3 mm or 1/16 to 1/8 inch
- Colour range: brown to black
- Distinguishing features: smooth, hairless body; emits a rotten coconut odor when crushed
What should I know about odorous house ants?
To get rid of odorous house ants, it helps to know how they live and behave:
- A colony of odorous house ants typically has multiple queens and nests. A small colony may have 30 worker ants and one nest. A supercolony can have 500,000 worker ants, many queens and many nest sites.
- Odorous ant colonies grow by ‘budding,’ or when queen and worker ants split from the main colony to establish new nests. Colonies also split when threatened, such as when exposed to ant repellent spray. Repellent sprays make odorous house ants panic; to survive the threat, they split into more nests. The more nests that exist, the more difficult it is to eliminate odorous house ants.
- Outdoors, the ants nest in moist areas that are close to food. In winter, odorous house ants coalesce into fewer nests. In summer, the ants spread out and occupy more nests.
- Odorous house ants prefer sugary foods and are often called ‘sugar’ ants. Outdoors, they eat sweet honeydew (made from plant sap by aphid, mealybug and scale insects), as well as proteins like live and dead insects. Indoors, the ants are attracted to sugary foods and spills, fruits, vegetables, meats and dairy products.
- The ants make trails from nests to food and back, and ants from multiple nests may participate in a trail. As such, you may notice that an ant trail branches out in different directions. Following the branches will help you locate multiple nests. As well, multiple ant trails may be entering the structure, so thoroughly inspect the building’s perimeter. Foraging trails typically are 33 to 157 feet long and are found on both horizontal and vertical surfaces. Get tips for how to follow ant trails.
- Odorous house ants forage for food day and night. During hot summer months, the ants are more active outdoors at cooler times of day and at night. They may come inside to forage when honeydew is harder to find, such as after heavy rains or in early autumn. An indoor nest of odorous house ants will forage inside year-round.
Where are odorous house ants found indoors?
Indoors, odorous house ants are found on countertops, in cupboards, sinks, appliances and anywhere food has been located. They may trail along baseboards and edges of carpet.
While the nests of odorous house ants usually are located outside, they may nest indoors near sources of moisture. They nest inside walls near plumbing and heaters, and under sinks, bathtubs and toilets.
Where are odorous house ants found outdoors?
Odorous house ants can thrive just about anywhere. Their shallow nests are typically found near man-made structures under leaf litter, mulch, logs, boards and landscape timbers. The ants may nest in stacks of bricks, lumber, firewood, cardboard and vinyl siding. The ants also will nest under the lids of box beehives.
Odorous house ants can be found trailing on tree branches, in landscape shrubs, and along sidewalks and foundations.
How do odorous house ants get in the house?
Odorous house ants get into homes and businesses through cracks in foundations, gaps in caulk around window and doors, and holes where wires and pipes enter the structure. Read our expert guide: How to Keep Ants Out.
What are the best ant killers for odorous house ants?
It is essential to use the right pest control products to kill odorous house ants or you will make the ant problem worse:
- Ant traps - The best ant killers for odorous house ants are ant traps (also called ant bait stations), which are filled with an insecticide bait. Foraging ants take the bait back to the colony where it is shared among the workers, larvae (baby ants) and queens. To eliminate odorous house ants, you must kill the queens. Place ant traps where the ants are trailing and near nests. Use slow-acting sugar- and protein-based baits. Learn more about ant stations and insecticide baits and how to use them.
- Diatomaceous Earth (DE) - Also called DE ant powder or DE ant dust, DE can help reduce the number of foraging odorous house ants, but it will not kill the queens and may make the colony panic and split. It is best applied to wall voids, behind baseboards and cabinets where the ants are active. The ants will walk through this natural desiccant, which scratches the waxy outer layer of their exoskeleton, causing them to dry out and die. Learn more about DE and how to apply it.
- Ant repellents - Repellents are not recommended for use on odorous ants because they will cause the colony to split into multiple nests, ultimately creating a bigger ant problem.
Also read:
5 Steps to Get Rid of Ants for Good
