Moisture ant is a general term used to describe two groups of ants that can inhabit structures in association with moisture. Cornfield ants are the larger of the two groups and the most common in Washington State. These ants are yellow to dark brown, monomorphic (same size), and approximately 1/8″ in length. Moisture ants usually inhabit rotten stumps or logs but can be found nesting in wet soil.
They will feed on other insects, sweet substances and honeydew from aphids. When these ants become a problem in homes or buildings they are found in close association with a moisture problem. They should not be considered a primary structural pest but an indicator of a pre-existing serious moisture problem. Control is structural in nature. The moisture source should be corrected and all rotten wood removed.