Odorous House Ant Tapinoma sessile
More commonly known as sugar ants, odorous house ants are very small black ants. All of the workers in the colony are the same size (about 2.5 mm). Although they don’t bite, sting or do any wood damage, odorous house ants can be very annoying as they frequently establish trails along kitchen counters, cabinets, sinks, and baseboards in their search for food. They can also be difficult to eradicate, since there can be several (or many) queens in several locations, the workers can all trail together regardless of their home colonies, and the colonies frequently move from place to place, both inside and outside.
When dealing with sugar ants, it’s generally a bad idea to spray the visible trails with a standard insecticide, as the sudden loss of so many workers tends to put the colonies under stress, which fractures the colony, forcing the queens to take workers & larvae and split up. This means you will have multiple colonies to deal with instead of one..
Sugar ants may be gradually eliminated with a variety of baits, but using baits alone can take an unacceptably long period of time. It is best to use a so-called transfer insecticide, with which the active ingredients are transferred from ant to ant, in conjunction with a baiting strategy. These types of insecticides are not available to the general public.