In the late fall, a homeowner found swarming ants in the house. The swarming activity occurred in one corner of a family room addition which was slab on grade construction. The family room was adjacent to the crawlspace under the main house. The homeowner attempted to spray and bait the ants but was unsuccessful. Their point of entry was never located.
Upon inspection by the operator, the ants were identified as large yellow (moisture) ants. No activity was found around the exterior of the house. The crawlspace was accessible, somewhat damp, and insulation batts were stapled between the floor joists. There was no apparent evidence of any activity, so some of the insulation was removed near the corner of the family room where the swarmers were found.
This exposed the colony which contained thousands of ants. The ants were in the insulation and the space between the insulation, joists, and subfloor. The ants and nesting site were treated with an aerosol residual insecticide, and the infested insulation was replaced.