Wood Destroying Organisms & Pests

Anobiid Beetle damage
Termites are among the most important structural insect pests in the Northwest. Only carpenter ants rival them in importance. Termites feed on wood or wood products, and their digestive tracts contain microorganisms which enable them to convert the cellulose in wood into usable food. Most termites need moist conditions to become established. For subterranean termites, the moisture source usually is the soil. For damp wood termites, the moisture comes from wet wood.Termites are social insects living in colonies comprised of a king and a queen (wingless adults or nymphs, depending on the species) and soldiers. The king and queen perform the reproductive functions of the colony, while the workers carry on all aspects of colony maintenance. The soldiers defend the colony.


Anobiid Beetle damage

These individuals, separated by divisions of labor, are referred to as castes. Therefore, there is a reproductive caste, a worker caste, and a soldier caste. There are two common species of termites in Washington. These include the Pacific damp wood termite, Zootermopsis angusticollis, and the western subterranean termite, Reticulotermes hesperus. (A third species, called the dry wood termite, has been found in this state on occasion but has not become established. They do not require high moisture level to live, and have occurred in furniture articles which, inmost cases, have been documented as imports from the South.) Subterranean and damp wood termites occur in both eastern and western Washington.

However, the subterranean termite occurs only as far north as Seattle in Western Washington and the damp wood termite has a limited distribution in Eastern Washington. Termites are often confused with ants. The termite has straight beadlike antennae, while those of ants are elbowed. The abdomen of the termite is broadly joined to the thorax (no waist), while the ant’s thorax and abdomen are joined by a narrow pedicel (wasp waist). Termite wings, both the front and the hind wings, are of equal size. The anterior wings of the ant are considerably larger than the posterior wings.


Dampwood Termite fecal pellets

By Arthur L. Antonelli, Ph.D., Extension Entomologist, WSU Puyallup.PACIFIC DAMPWOOD TERMITE
This termite is our largest species. The winged forms may exceed one inch in length (25 mm) including the wings. They are cream-colored to dark brown. The soldiers have a large reddish brown to blackish head and a cream-colored body. They are approximately 3/4 inch long (20 mm) with the head and jaws comprising about one-third of their length. Since there is no worker in this species, the nymphs perform this function. They are white to cream-colored and about 1/2 inch (13 mm) long a high moisture level is necessary for attack and establishment.  Although soil contact is not necessary, wood-soil contact often leads to damp wood termite infestation. More often, wood that has become fairly saturated due to leaky pipes or poor gutters, or damp support beams due to poor ventilation, are the primary points of infestation for these pests. Rain-soaked firewood can also attract termites. They live in the wood they feed on—they do not live in the soil. Once established, these termites can extend their activities into sound wood, even relatively dry wood. As colonies mature, they produce winged reproductive that leave the nest in swarming flights. These flights usually occur on warm evenings in late summer or fall, especially after rains. If the proper conditions persist, the colony will continue to grow and feed, producing great structural damage. Termites are not easily observed by the homeowner because they hide themselves to prevent moisture loss since they depend on moisture. Certain signs will give clues to the presence of a termite colony in the home. Termite swarms coming from the home are probably the most obvious sign.Inspection techniques (given later) will also aid in determining their presence. Damp wood termites produce distinctive fecal pellets which can aid in their identification when damaged wood is examined. Termite identification is essential since each of our termites requires very different control efforts. Damp wood termite fecal pellets are approximately 1/25 inch (1 mm) long and slightly hexagonal. If the wood is extremely damp, these pellets will be found adhering loosely to the sides of the galleries; otherwise, they will be scattered on the floor of the galleries.



Termite Damage

WESTERN SUBTERRANEAN TERMITEThese are small termites. The winged form is approximately 3/8 inch (8–9 mm) long including the wings. They are dark brown to brownish black with brownish gray wings. The soldiers have a cream-colored head with black jaws and a grayish white body. They are approximately 1/4 inch (6 mm) long. Nearly half their length is head and jaws. The “worker” caste is grayish white and about 3/16 inch (5 mm) long. They live in the soil in nests which may originate in buried stumps or logs that may be as deep as 10-20 feet (3–6m).   Since subterranean termites live in and obtain their moisture from the soil, damp wood is not essential for attack.This makes any wood structure a potential site for subterranean termite feeding. The most frequent type of infestation is in buildings constructed near or on preexisting nests. Cement slab foundations are no deterrent since eventual frost cracks, cold joints between slab and foundation walls, and areas around plumbing provide easy entry for these termites. Indications of subterranean termite infestation are swarming behavior, damage signs, the distinctive tapping sounds that the soldiers make when disturbed, and especially by the presence of shelter “mud” tubes. The tubes provide protection from natural enemies and prevention of moisture loss. Although clearly diagnostic of subterranean termites, tubes are not always present. Fecal pellets of subterranean termites are often clumped in the galleries or incorporated into the shelter tubes and feeding areas of the wood and rarely are loosely scattered as with damp wood termitesFecal material packed in the galleries of the wood appear to be “scaly” and offer a distinctive clue to damage from subterranean termites rather than some other wood eating pest— even in the absence of this termite. Mature colonies swarm annually, while colonies from a primary pair may not produce swarms for several years. They may swarm at any time of the year, depending on climatic conditions. In eastern Washington, swarming is predominantly in the spring, while in western Washington, swarming is predominantly in the fall.PREVENTION, DETECTION, AND CONTROLAvoiding situations that lead to dampening or rot of structural wood can prevent termite attack and establishment in most cases. Prevention can be further insured by periodic home inspections. This can be done by considering all the suggestions mentioned and looking for violations at these points. Final steps would involve inspecting the foundation and crawl space area. Outfitting yourself with gloves, coveralls, and a hat will prevent direct skin contact with cobwebs, protruding nails, etc. While searching under the house, use a sharp pick or screwdriver to test the support beams, floor joists, sills, and other wooden structural material for signs of decay, dampness, or pest infestation. Also look for piles of sawdust and dead insects. Point out these clues to professionals from whom you may seek assistance or advice. While you are there, also look for leaky pipes and inspect the vent screens to see that they are not plugged. If you prefer not to do these things yourself, you can employ someone to do it for you. There are reputable pest control operators (exterminators) who will do this as a separate service for a reasonable fee. Control methods of termites differ with the species to be controlled. If dampwood termites\ are the problem, it is likely that correction of the conditions that led to their establishment (for example, leaky pipes, wood-soil contact, etc.) will be effective in eliminating them. If subterranean termites are the problem, chemical treatment is essential. Current registered termiticides can be found in the Pacific Northwest Insect Management Handbook. All county Cooperative Extension offices have a reference copy at their disposal.

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