Tapinoma sessile
Ant
1/16 to 1/8 inch
Brown to black
Queens 1 to 2 years, workers a few months
About the Odorous House Ant
The odorous house ant is Michigan's most common indoor ant. Crushed workers release a distinctive rotten-coconut or blue-cheese smell, which is how the species earned its name. Colonies contain 10,000 or more workers and multiple queens, making them difficult to eliminate without professional treatment.
Habits & Behavior
Odorous house ants nest in wall voids, under floorboards, behind baseboards, inside insulation, and beneath mulch and landscape timbers outdoors. They relocate nests every few weeks in response to disturbance or weather. They forage along baseboards, counters, and plumbing lines searching for sugary foods, grease, and dead insects.
Signs of a Odorous House Ant Infestation
Trails of small brown ants along kitchen counters, baseboards, sinks
Crushed ants producing a rotten-coconut or blue-cheese smell
Ant activity centered around sugar, honey, syrup, pet food, ripe fruit
Ants entering through window frames, door thresholds, electrical outlets
Heavy spring and fall activity after rain
Odorous House Ant Pressure in Michigan
Odorous house ants are abundant throughout Metro Detroit. Population peaks in May to June (spring rains) and September to October (fall cooling). Heavy mulched beds, shaded foundations, and damp landscape features accelerate colony growth.
How BTR Treats Odorous House Ant Infestations
BTR uses non-repellent spray chemistry plus sugar-based and protein-based gel baits. Spraying with repellent products causes odorous house ant colonies to fragment (budding), creating multiple smaller colonies. Non-repellent chemistry allows workers to carry active ingredient back to the queens. Most treatments clear in 2 visits across 4 weeks.
Prevention Tips
Seal all small gaps around windows, doors, and foundation penetrations. Fix outdoor drainage issues. Keep mulch 12 inches from the foundation. Clean up spilled pet food and fallen fruit immediately. Wipe counters nightly.
Frequently Asked Questions About Odorous House Ants
Why do odorous house ants appear after it rains?
Spring and fall rains flood outdoor nests, pushing ants indoors in search of dry shelter. Heavy rain also disrupts foraging trails, causing colonies to relocate. Ants follow moisture gradients to plumbing lines and wall voids.
Will store-bought ant spray work on odorous house ants?
Usually no. Repellent sprays cause the colony to split into multiple smaller colonies (budding), making the problem worse. Non-repellent professional chemistry and slow-acting baits are required for full colony elimination.
How long does BTR ant treatment last?
Most odorous house ant treatments clear in 2 visits across 4 weeks. Treatments include a 90-day warranty. Annual perimeter treatments prevent seasonal reinfestation.
Can I crush the ants to get rid of them?
Crushing odorous house ants releases alarm pheromones that signal nearby workers to relocate and establish new nests. Crushing makes infestations spread. Use gel bait or wait for professional treatment.
Are odorous house ants dangerous?
Odorous house ants do not sting, transmit disease, or damage wood. They are a nuisance pest, but heavy trails over food-preparation surfaces create sanitation concerns.
Odorous House Ant Problem? BTR Can Help Today
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