subject: Determining Carpenter Ants Presence Of Infestation [print this page] The presence of large ants usually is the first sign of infestation. Carpenter ants tend to be most active between 10 pm and 2 am.
Evidence of Infestation
Presence of ants (workers or winged reproductives): An occasional ant may be a scout looking for food and may not indicate the presence of a nest, but continuous or numerous ants are a sign of nesting.
Sawdust: Accumulating in piles or caught in spider webbing; has a finely-shredded appearance. Do not confuse with small sawdust from construction
Trails
Sounds: Rustling or tapping noises produced when disturbed ants rasp the substrate with their mandibles or gasters or when excavating wood.
Coarse sawdust is a sure sign, but it is often difficult to find the nest. At night, turning on a light to observe ant activity around a sweet that has been left out may reveal an "ant line" to and from the nest. Sometimes the insects' activity can be heard in walls. Tapping areas suspected of harboring nests may produce a hollow sound, and some excited ants may appear.
Type of House Likely to be Attacked
Dr. Hansen's research showed that some common elements accompanied infestations. Although other types of structures were attacked, most infestations were in houses with these characteristics:
Wood frame
Crawl space
Cedar or plywood siding
Moderately to gently sloping roof
5-25 years of age
Vegetation (trees and shrubs) surrounding the house
"Structures located near the edge of the forest were more liable to attack than those located further away." This is because the ants which have well-established nests in trees or stumps can easily move to the nearby house and establish satellite colonies.
Trail Locations Inside Structures
Again ants prefer natural, easy and protected routes:
Edges of cabinets, furniture
Excavated trails through insulation in wall voids
Along wiring or plumbing which cuts through studs
Wires or branches coming to the house
Root channels from infested trees or stumps which go beneath the house.
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