Ants are a common insect pest that everyone has come across in their kitchen or at a picnic at some time or another. While dealing with ant pests is no one’s idea of fun, one species stands out as the most annoying and difficult to control. The odorous house ant, which is native to the U.S., has earned the honor of being the most common and difficult ant pest to control in Maine, as well as throughout much of the country.

The odorous house ant gets its name from the foul odor, described as smelling like rotten coconut or pine, it emits when crushed. Odorous house ants are often confused with pavement ants, which are usually easy to control with commercial baits. They are quite small in size, at 1/16 to ⅛ inch long, and brown to black in color. Odorous house ants can only be differentiated from pavement ants when magnified, with the best indicator being the single node or bump found between the thorax and the abdomen of odorous house ants, whereas pavement ants have two of these nodes. It is important to know which one you are dealing with, as odorous house ant infestations are notoriously difficult to eradicate.

In addition to being the most common ant pest, odorous house ants are also the most difficult to control due to their habit of establishing multiple indoor nests. One nest colony can contain anywhere from 100 to 10,000 ants. Odorous house ants will establish nests in almost any location you can imagine, particularly near sources of moisture. They will often nest outdoors under mulch, stones, flower pots, wood piles, pavement, and house siding, only entering a home to forage for food and water. However, these nests tend to be mobile, and colonies will relocate often and very quickly in response to disturbances from humans or other insects or animals, as well as changes in weather. This can bring odorous house ants inside where they will build nests in places such as wall voids, potted plants, and appliances. When disturbed or threatened, colonies will also split into sub-colonies and scatter to other areas of a home to build new nests. This makes eliminating an infestation of odorous house ants can seem impossible, as you have to locate every nest and kill off the ants before they realize what’s happening and the survivors simply branch off and relocate to build yet more nests you will have to find and destroy. These hardy pests often require the knowledge and experience of a pest control professional to successfully eradicate them.

Have you ever had to deal with an infestation of odorous house ants?