Drywood Termites

Introduction

The common name refers to this termite’s southeastern United States distribution, and to the fact that it lives in wood which has a very low moisture content (12% or less). This is the most widely distributed drywood termite in the eastern United States, occurring primarily coastally from South Carolina westward to Texas. It is also found in the Bahamas and Bermuda. However, it can readily be transported outside this area in infested furniture, pictures frames, etc.

Recognition

Swarmer. About 7/16-1/2″ (11-12 mm) long including wings; head width 1/32-1/16″ (1.20-1.35 mm). Head and body pale yellowish brown to pale reddish brown, wing with sclerotized (hardened and pigmented) veins pale yellowish brown in outer half of wing. Head with 2 ocelli almost round. Antenna with 11-14 segments. Front wing with 3 dark, heavily sclerotized veins in front half/portion; median vein (M) unsclerotized, running midway between sclerotized veins above and unsclerotized cubitus (Cu) below, and ending near wing tip even if branched along its length; not hairy. Tibia with spines lacking along length, apex with 3 spines.

Soldier. Forehead slopes down gradually from top of head, head flattened in side view, and head orange to reddish brown with eye spot whitish. Mandibles with an unequal number of teeth on each member of pair. Tip of labrum (upper lip) bluntly pointed. Antenna with 11-14 segments, 3rd segment as long as 4-5 combined and less than twice width of 4th. Pronotum as wide as or wider than head (dorsal view), about 1/16″ (1.3-1.6 mm) wide.

Similar Groups

1. 1. Incisitermes milleri with swarmer shorter (1/4-5/16″/7-8 mm) including wings, with head, thorax, and body dark brown, head width (through eyes) about 1/32″ (0.9 mm), and ocellus oval; soldier head length about twice width, antenna with 10-11 segments, and pronotum about 1/32″ (1 mm) wide; rare, found in West Indian hardwood forests of Key Largo and Elliott Key.
   2. Incisitermes schwarzi with swarmer longer (1/2-9/16″/13-15 mm) including wings, with head and body medium brown, head width (through eyes) 1/32″ (1.40-1.52 mm), and ocellus oval; soldier antenna with up to 16 segments, 3rd segment longer than 4-5 combined, tip of labrum (upper lip) squared off, and pronotum about 1/16″ (1.5-1.9 mm) wide.
   3. Incisitermes minor with swarmer wing membrane blackish and front wing with unsclerotized median vein (M) curving forward near mid-wing to join sclerotized radian sector vein (Rs); soldier with 3rd antennal segment greatly enlarged and clublike, as long as or longer than segments 4-6 combined, and about twice as wide as 4th segment.
   4. Formosan subterranean termite (Coptotermes formosanus) swarmer has wings densely covered with hairs; soldier with mandibles lacking teeth.

Damage & Signs of Infestation

Drywood termites eat across the wood grain and make chambers and/or galleries connected by tunnels. Their gallery and tunnel walls are velvety smooth, and no soil is present. Usually there are fecal pellets present which are hard, less than 1/32″ (1 mm) long, elongate-oval with rounded ends, and have 6 concave sides. Signs of infestation include swarmers, shed wings, piles of pellets, termite plugs which seal all openings in infested wood, and surface blisters caused by older enlarged galleries very close to the wood surface.

Biology

Drywood termites are non-subterranean termites they do not live in the ground, require no ground contact, and do not build mud tubes.

Their colonies are located in the wood they eat and are of small size when compared to subterranean termite colonies, usually numbering about 3,000 individuals after 15 years. There is no worker caste and the immatures/nymphs perform all tasks typically done by workers.

The life history of the southeastern drywood is similar to that given for the western drywood termite; see page 10.4.2.

Swarming takes place at night, peaking between 8 and 10 pm, with swarmers attracted to lights. Swarming occurs primarily from March to mid-August, peaking from late May through mid-June.

Habits

Swarming southeastern drywood termites fly to structures and infest wood directly. They typically first infest exposed wood such as window/door frames, trim, fascia boards, eaves, siding, etc., and later may move into attics. In southern Florida, they are found in attics where temperatures average 83-110°F (28-43°C), but may exceed 131°F (55°C). Here they locate their colonies in wood with more favorable temperatures, such as ceiling joists that have their bottom sides cooled by the A/C below and modulated by surrounding insulation. When swarming, they often re-infest the same structure.

These termites are often distributed by human activity, commonly by transporting infested furniture, picture frames, and wood to new areas. However, they have not become established outside of their normal southeastern and mostly coastal range. 

Termite Control Naples

Since infestation is direct and not via the ground, the most successful methods of control are fumigation, or local treatment or replacement of the infested wood. Fumigation is recommended if infestations are widespread and/or difficult to access whereas, local treatment with pesticides or other means is prudent where infestations are isolated and accessible.

If the infestation is confined to a piece of furniture, picture frame, etc. which can easily be removed, then it may be treated via heat or cold if practical, or the infested item destroyed. Other methods/means available include the use of microwaves, the application of electrical currents (high watts, low amps), etc.
Localized infestations may be treated via intergallery injection or surface treatment with pesticides which are labeled for these termites.