Dampwood Termites

Because of their moisture requirements, structural infestations of dampwood termites are associated with sources of free water.

These include wood-to-soil contact, wood exposed to roof leaks, or wooden siding or ornamentation exposed to rainfall or sprinkler irrigation.

Because these same conditions are conducive to fungal decay and subterranean termites, it is in the interest of the property owner to correct these moist conditions. Wood that has been pressure-treated with chromated copper arsenate (CCA) is resistant to infestation. Neotermes infestations can extend into sound dry wood several meters away from the moisture source, but once the remote source of moisture is removed, the colony will gradually decline and succumb to desiccation. Like drywood termites, dampwood termites produce fecal pellets, but because of the moist conditions of the gallery system, the pellets loose their distinctive shape and form amorphous clumps or paste. The degree of shape degradation is directly related to moisture content.

Neotermes castaneus, in particular, prefers to nest in living trees. Colonies are often discovered in trees when they are pruned or damaged by windstorms. Robust colonies of N. castaneus apparently live in trees and palms for years or even decades before they are discovered. In one case, alates of N. castaneus were emerging from a Ficus tree in an indoor shopping mall in New Jersey many years after the tree was delivered from Florida. Although the galleries may weaken trunks and branches, the overall health of the tree is usually not directly affected. The termites appear to limit their feeding to the dead xylem tissues while avoiding the cambium. When galleries filled with live N. castaneus are exposed, they exude a characteristic fecal or skatole- like odor.

Pest Classification

The limited conditions that support colonization by dampwood termites relegate these termites to minor pest status. Wood damage, however, can be severe after several years if infestations are left alone. Damage to trees and branches may cause weakening but does not appear to harm tree viability although hollowing from galleries might promote secondary fungal intrusion.

For reasons mentioned above, eliminating conditions of moisture can control structural infestations of Neotermes. As with the preventative management of subterranean termites and wood decay, wood-to-ground and wood-to-water contact should be eliminated to prevent colonization by dampwood termites.

When untreated wood cannot be removed from a moisture source, chemical treatment may be necessary. Boron-containing salts such as disodium octaborate tetrahydrate (Tim-bor) are water soluble, so they tend to be drawn into dampwood termite-infested wood. Borate treatments can be phytotoxic, however. If desired, galleries in trees or structural members can be injected and drenched with site-specific insecticides. On direct contact, these termites are susceptible to all chemical insecticides.