Eastern Subterranean Termites

Introduction

This is the most common and widely distributed termite in North America. It occurs south of the line where the average annual minimum temperature is -22°F (-30°C). This includes southern Ontario, Canada, and southward through the eastern United States and into Texas. It has also recently been found in California. This species is also found in parts of Europe.

Recognition

Swarmer. About 3/8″ (10 mm) long including wings. Body dark brown to almost black. Fontanelle (frontal gland pore) present, may be inconspicuous. Front wing with 2 dark, heavily sclerotized (hardened) veins in front portion, other veins unpigmented except for basal third. Wing translucent (slightly milky) to slightly smoky, with a few barely visible hairs. Front wing scale distinctly larger than hind wing scale, may overlap basal portion of hind wing scale. Leg with tibia darker than tarsus.

Soldier. Head rectangular in shape, not narrowed toward front, length about 1.5 times width. Fontanelle (frontal gland pore) dorsal and indistinct. Mandibles lack teeth and with tips, especially left, incurved at about 70-90°. Pronotum flat, almost as wide as head, with width usually greater than 0.90 mm.

Similar Groups

1. 1. Dark southeastern subterranean termite (Reticulitermes virginicus) swarmer with wings colorless and ocelli less than their diameter from compound eye; soldier head length with mandibles 2.7 mm or less.
   2. Formosan subterranean termite (Coptotermes formosanus) swarmer has wings densely covered with hairs, body pale to brownish yellow and larger (about 1/2″/12-13 mm); soldier with head rounded on sides and tapered toward front, with anterior tubelike fontanelle.
   3. Western subterranean (R. hesperus) swarmer with wings brownish gray and tibiae slightly darkened; soldier with head length fully twice width.
   4. Light southeastern subterranean termite (R. hageni) swarmer with body pale yellowish brown; soldier with pronotal width less than or equal to 0.70 mm, mandible points incurved at about 45°, and head length with mandibles 2.7 mm or less.
   5. R. tibialis swarmer with wings whitish, almost colorless and tibiae black to sooty (vs pale tarsi); soldier with pronotal width greater than 0.70 mm mandible points incurved at about 70-90°.
   6. Most other termite swarmers have 3 or more pigmented veins in front wings.

Damage & Signs of Infestation

Subterranean termites eat mostly the spring wood and leave the harder summer wood which they cannot effectively digest. Hence, damaged wood appears to be layered. Also, soil is typically found in the galleries.

A typical mature colony may consist of 60,000 to over a million workers. Sixty thousand workers can/may eat 1/5 ounce or 5 grams of wood each day. At this rate, such a colony could completely consume 2 1/3 linear feet of a pine 2″x4″ board in 1 year. However, there may be several colonies associated with a single building.

Biology

Eastern subterranean termites have 3 castes: worker, soldier, and reproductive (primary and secondary). Colony founding via alates or swarmers proceeds with the swarmers associating in pairs, breaking off their wings, and burrowing into the soil. Here they mate and only a few eggs are produced the first year. When the queen is mature she will produce about 5,000-10,000 eggs a year. The queen may live for many years, and individual soldiers and workers may live 1-2 years.

Several years (often 5-10) are required before the colony reaches the typical mature size of 60,000 or more workers. Under ideal conditions a few alates/swarmers may be produced after 3 or 4 years. Swarming typically occurs during the spring (late winter in Florida), but it may possibly be followed by one or more smaller swarms until winter; in heated structures, swarming can occur during the winter. Swarming occurs during the daytime, typically during the morning of the day following a warm rain.

In the extreme northern states and Canada, swarmers are rarely seen. Colony distribution is patchy because the termites are usually spread in infested wood and wood products such as lumber and firewood. Colony size is much larger, with colonies of 2-3 million foragers not uncommon. These large colonies forage over larger areas of about 3-12,000 sq ft (279-1,115 sq m). They actively feed in living trees and free-standing poles, in addition to structures. Such colony distribution, size, and foraging patterns are similar to those of Formosan subterranean termites.

These termites have been observed to forage a maximum of 151-793 ft (46-79 m) depending on colony size; smaller colonies tend to forage a shorter distance.

Habits

Eastern subterranean termite colonies are usually located in the ground. Location is usually below the frost line, but above the water table and rock formations. Mud tubes are built to cross areas of adverse conditions between the colony and food sources. They can enter structures through cracks less than 1/16″ (1-2 mm) wide. However, if a constant source of moisture is available (like leaky pipes), colonies (called secondary colonies) can exist above ground and without ground contact. Also, true aerial colonies (no ground contact ever existed) are known to exist.

Termite Control Naples

Control involves placing a chemical treatment zone (second-generation non-repellent pesticides work best) and/or an in-ground perimeter monitoring-baiting system between the termite colony and the wood of the structure. In addition, all wood-to-soil and rigid foam board/foam-to-ground contact should be eliminated (the building owner’s responsibility), any wood debris must be removed, and the wood moisture content should be reduced to below 20%. Secondary and aerial colonies are controlled by correcting the moisture problem to dry out the moisture-source area. When it is desirable to rapidly reduce the secondary infestation, this can be done by intergallery injection or surface treatment with a pesticide labeled for these termites. Also available are above-ground termite baiting systems that are placed directly on the termite infested  wood.