In much of the United Sates, drywood termites either cannot be found, or are of little significance as pests of structures, but this is not the case in the southwest where drywood termites inflict millions of dollars in property damage annually. Unlike subterranean termite colonies, drywood termite colonies are contained entirely within single pieces of above ground wood, such as fallen branches, logs and tree stumps. While subterranean termite workers infest structural wood from the ground up after leaving their nest, the only termites that leave drywood termite nests are winged reproductives (alates), and therefore, only alates establish drywood termite infestations. Drywood termite infestations do not cause as much damage as subterranean termite infestations, but drywood termites possess several traits that make them difficult to detect within infested homes.
Since winged alates initiate drywood termite infestations during swarming season, infestations can be located anywhere on, or within a home including wood beneath roof shingles, exterior wood siding and substructural wood in crawl spaces. This makes drywood termite infestations more difficult to detect than subterranean termite infestations, which are usually limited to the lowest structural wood components within homes. Subterranean termites also leave behind mud tubes indicating their presence within structural wood, but drywood termites leave behind very few, if any, signs of their presence. It is also important to note that, unlike subterranean termites that infest only moist wood, drywood termites are much more tolerant of dry conditions, which allows them to infest just about any wood source, moist or dry. Drywood termites are also able to eat into hardwood portions of wood, which subterranean termites generally avoid as being too dense for them to chew.
Due to being contained within single wood items, drywood termite colonies contain far fewer individuals than subterranean termite colonies. Since drywood termite nymphs do not build mud tubes to access other wood sources outside of their colony, they can only move to new pieces of lumber by traveling through the points where two pieces of lumber meet. Drywood termites carve “kick-out” holes on the surface of infested wood in order to discard their fecal pellets (frass). Finding small holes on the surface of structural wood, or piles of sawdust-like frass on the ground indicate that a dry wood termite infestation has been established and has caused damage.
Have you ever found signs of drywood termite activity in your home?