Termite I.D.

AVOIDING DAMAGE CLAIMS. Proper pest identification is perhaps even more important in termite work than general pest control work. Misidentification of the termite involved in a particular infestation can lead not only to repeated retreats but also to damage claims and even lawsuits. Imagine, for example, a PCO located in New Orleans identifying a customer’s problem as drywood termites when , in fact, the swarmers found inside the house are Formosan termites. Any number of structural fumigations would not eliminate this customer’s problem.

PCOs in northern states may ask, "We only have subterranean termites in our part of the country; why should I learn how to identify other types of termites?" Many people either buy furniture made in southern states or have lived here and moved north. Drywood termites infest many types of wood items, especially antique furniture. Swarms of drywood termites inside structures have been observed numerous times in homes located in the North. Additionally, in many parts of the country PCOs have been called to identify dampwood termites living in wood shipped from the West Coast.

In one such situation, a PCO sold a treatment for subterranean termites after a swarm appeared inside a home. The PCO bothered only to confirm the swarmers were termites, even though the bodies of the termites were brownish in color. Swarms continued each spring for three years and retreatments were made annually along the foundation of the home. A few of the swarmers were finally brought to the staff entomologist who identified them as alates of the powderpost termite, Cyptotermes brevis. This termite, a species of drywood termite, is common in Florida and infest furniture. A visit to the customer’s house revealed that a piece of furniture in the home was purchased in Florida a few yeas before the problem initially appeared. The infestation was located in this piece of furniture and was eliminated by drilling two small holes into the piece of furniture and injecting less than 1 ounce of PT-270 Dursban. This happened in Chicago, where winters can be quite severe. Needless to say, after this experience, all service technicians in the company received instruction in proper termite identification.

TERMITE ANATOMY. Correct identification of the four types of structure-infesting termites is not difficult. This article will discuss the identifying characters of these termites in easily understood terms.

In order to identify termites, one must be familiar with the various body parts used in identifying these insects. Termite colonies are characterized by several different castes or forms of individuals. The alates (swarmers) and the soldiers are the only individuals in the colony which can be used for identification purposes. A technician, therefore, must have either a soldier or an alate if he wishes to identify the termite involved.

Alates. Termite alates closely resemble the winged reproductives produced by ant colonies. Note that all four wings of the alate are the same size. The hind wings of an ant swarmer are much smaller than its front wings. The termite alate’s waist is broad in shape while the ant swarmer’s waist is pinched or narrow. The antennae of the termite alate are straight. An ant swarmer’s antennae are elbowed.

The primary difference between the various species of termites is seen in the wings. A hand lens is needed to see the identifying characters of the termite’s wings. When a termite alate specimen is found, the wings should be removed and placed on a piece of white paper. A pin or needle may be needed to hold the wing flat on the paper so the veins in the wing can be examined fully.

Many times, only wings are found in window sills. Even if only wings are found, identification of the type of termite involved can still be determined. What follows is a discussion of the identifying characters of the various types of termite alates.

1. Subterranean termites: The wings of a subterranean termite have two heavy or dark veins running the length of the upper margin of the wings.

The native subterranean termites, Reticulitermes, are normally brownish-black or black in color. However, two species of Reticulitermes found in the northern states are brown in color. Although these two species are not often found in structures, technicians should not rely on color alone to identify termite alates. Look for the two dark veins at the upper margin of the wings.

2. Formosan termites: The Formosan termite, Coptotermes formosanus, is a species of subterranean termite. Therefore, it has two dark veins at the upper margin of its wings. The difference between the Formosan termite and other subterranean termites is the presence of rows of fine hairs running along the veins of the Formosan alate’s wings.

The body of the Formosan termite alate is brown like many species of drywood termites. The Formosan termite also swarms in the evening, as do many drywood termites. Therefore, correct identification is crucial. Check for the two dark veins with tiny hairs at the upper margin of the wings to determine if Formosan termites are involved instead of drywood termites.

3. Drywood termites: The wings of drywood termite alates differ from those of subterranean termites by having three or more dark veins at the upper margin of the wings instead of only two veins.

The body color varies among the different species of drywood termites. Do not attempt to use color to distinguish between the various types of termite alates.

4. Dampwood termites: The alates of dampwood termites, Zootermopsis spp, are quite large, up to 1 inch long or more including the wings. Like the drywood termite alate, the dampwood alates wings have four dark veins at the upper margin of the wings. The dampwood swarmer can be distinguished by its large size and the fact its antennae will have more than 23 segments.

Soldiers. Soldier termites are identified by examining the shape of the head and the mandibles. A soldier termite’s head is enlarged and hardened, giving it a dark appearance. The color can vary from light brown to black depending on the species involved. Except during the swarming season, a soldier termite must be found in order to identify the species involved. In some cases, this will involve breaking wood apart to locate a soldier.

What follows is discussion of he differences between the various types of termite soldiers.

1. Subterranean termites: Subterranean termite soldiers have a rectangular shaped head which is tan in color. The mandibles do not have any teeth along their inner margins. A few species may have only a single tooth on one mandible.
2. Formosan termites: The head of a Formosan termite soldier is rounded or triangular in shape. Like the native subterranean termites the mandibles of a Formosan soldier do not have any visible teeth.
3. Drywood termites: The head of the drywood termite soldier is rectangular in shape like the native subterranean termites. The mandibles of the drywood soldier, however, have teeth present along the inner margins of both mandibles.
4. Dampwood termites: The soldiers of dampwood termites are quite large except in newly formed colonies where the soldiers may be much smaller. Like the drywood termite soldier, the dampwood soldier has a rectangular shaped head and teeth present along the inner margins of both mandibles. The antenna of the dampwood termite soldier, however, usually has more than 32 segments.
5. Powderpost termite: The powderpost termite is a species of drywood termite which commonly infests furniture in Florida. The soldier has a unique, plug-shaped head which makes it easy to identify.
6. Nasute termites: Two species of termites found in the southwest United States have soldiers with heads equipped with a thin tube resembling a small "cannon". This shape of head is referred to as nasuitiform and termites with these characteristics are referred to as nasute termites. These termites do not infest structures but have been found on rural properties near structures in south central Texas.

USEFUL FIELD GUIDE. Once a person has seen the different types of termite alates and soldiers, the differences between them become more obvious. This guide can be used to identify termites in the field.

If a termite is encountered which cannot be identified, place specimens of soldiers and/or alates into 70

percent rubbing alcohol in a vial and send them to the entomology department of a local university or the cooperative extension service in your state for identification. Remember all pest management programs begin with correct identification.

Stoy Hedges a Registered Professional entomologist, is a frequent contributor to PCT.