Destructive Termites in northern California
Identification of the main destructive species

IMPORTANT: It is critical to identify the species and habits of destructive termites in order to formulate an appropriate control program. The species that cause severe structural timber damage to homes in northern California are (1) Western subterranean termites (2) Western drywood termites, and (3) Pacific dampwood termites.
CONTENTS: updated - the destructive termite species in nothern California; where they are found; their destructive nature and capabilities; the life cycle of each species; the fascinating life of a queen termite, king, armoured soldiers and the colony's tireless worker termites that do all the damage; identification tips and consumer protection advice on how to protect your home from a termite infestation.

Western subterranean termites

Western subterranean termites regularly infest homes in British Columbia, Washington State, Oregon, Idaho, California, western Nevada and western Mexico.

They cause severe economic loss to homeowners in northern California, particularly in and around the San Francisco Bay Area, Santa Rosa, Sacramento, Fresno and Monterey regions.
The Western subterranean termite is a serious economic timber pest causing millions of dollars of damage throughout northern California. It is estimated that more than 1 in 5 homes in the urban areas of most northern California cities have been or will be attacked at sometime by these voracious little insects.
AREAS of HIGHER RISK in NORTHERN CALIFORNIA include Alameda, Antioch, Berkeley, Carlsbad, Chico, Chino, Citrus Heights, Clovis, Concord, Cupertino, Daly, Danville, Davis, Elk Grove, Fairfield, Folsom, Fremont, Fresno, Gilroy, Hayward, Lake Forest, Livermore, Lodi, Madera, Manteca, Merced, Milpitas, Modesto, Mountain View, Napa, Newark, Novato, Oakland, Palo Alto, Petaluma, Pittsburg, Pleasanton, Redding, Redwood City, Richmond, Rocklin, Rohnert Park, Roseville, Sacramento, San Francisco, San Jose, San Leandro, San Mateo, San Rafael, San Ramon, Santa Clara, Santa Cruz, Santa Rosa, South San Francisco, Stockton, Sunnyvale, Tracy, Turlock, Union, Vacaville, Vallejo, Walnut Creek, Watsonville, Woodland, Yua and surrounding areas.

Identification of Timber Damage

Western subterranean termites are highly destructive to douglas fir and other common building timbers widely used in the construction of homes in northern California. In large numbers, the subterranean worker termite will rapidly devour the internal spring wood sections; preferring to leave the harder summer wood sections.

  As`a result, infested timbers are often left as a thin external shell, with layered "honey-comb" hollow sections (as illustrated) packed with moist soil. Western subterranean termites thrive in a moist dark environment. Moisture and humidity control are essential for their survival.

The life-cycle of subterranean termites

Biology of Western subterranean termites

Western subterranean termites are a secretive, yet highly social insect. They develop huge underground nests, containing a queen, king, winged reproductives (young kings and queens) or "alates", soldiers and workers.

Queen, King and attendant Workers

Worker Termites - do all the damage

The queen termite is an egg laying machine, her body is enormous compared to her off-spring and she can live more than 25 years and produce more than 2,000 eggs a day.

The king and queen live in a central chamber and are feed and attended to by the worker termites.

Worker termites are by far the largest caste in the Western subterranean termite colony and
the one that does all the damage. They carry out all work in the nest, including gathering food (timber and other cellulose), constructing tunnels, repairing and enlarging the colony nest, grooming and feeding the soldiers, the king, queen and young nymphs in the nursery.
Identification: Western subterranean worker termites are small in size, about half the size of match-head or 1/8" long. They are a creamy translucent colour, soft bodied, have no wings, are sterile, blind and work 24 hours a day for their entire adult life-span.

Soldier termites are the defenders of the colony, particularly against marauding ants - with whom they have been at war for more than 250 million years.
Identification: the soldier termite has an orange coloured, rectangular armoured head, with mandibulate pinchers which they use to crush the ants. On their forehead is a fontanelle (frontal gland hole) used to squirt a sticky latex to ensnare the ants. The soldier's mandible pincers are curved at about 70 to 90 degrees. The body of the Western subterranean termite is flat, with the width of approx 1/32”.
Consumer Note: If you open termite infested timbers or their mud tunnels or shelter tubes, it is the soldier termites that rush out to guard the area whilst the workers repair the breach. The identification of these insects as "termites" means an immediate professional inspection and protective measures are essential to avoid further ongoing or extensive damage. Remember: the standard home insurance policy in northern California, does NOT cover the costs of repairs or replacement of termite infested timbers in a home.

Swarmers or the reproductive termites - scientifically called "alates" are commonly seen by homeowners in northern California, when they swarm in large numbers, generally in the spring, during daylight. They have eyes, are poor fliers but can be swept hundreds of yards, by the wind. When they land, they drop their wings, find a mate to become king and queen of a new termite colony.
Identification: Western subteranean termite "swarmers" are about 3/8" in length, including wings. They have a dark brown body and a small fontanelle (frontal opening) on it's head. Their wings are a brownish grey, with two dark solid veins along the forefront of the front wings, which are distinctly larger than hind wings.
When do they swarm? In the northern part of their range, swarming takes place in the spring, but without rain. In the southern areas, swarming usually follows rain. Occasionally, a few smaller swarms may occur during the summer. Swarming most often occurs during the morning following a warm rain shower whereby the soil temperature is around 70°F. The swarmers are emitted in their thousands when a mature termite nest is large and well established.
Consumer Note: If you find swarmer termites in or around your home, it is a sure sign a large nest is close by and that your home is at high risk of a termite infestation.
The termite colony may contain more than a million termites foraging over a 12,000 square feet range, and actively feeding on trees, buildings and other timber structures.
Colony nest development is slow in the first few months, with the egg-laying capacity of the queen termite peaking after a few years, producing up to 10,000 offspring a year. The queen may live for many years and workers up to two years.
The colony nests of Western subterranean termites are usually located in the ground below the frost line, but above the water table. Mud galleries or "shelter tubes" are constructed across hard objects in order to gain access to timber food sources.
Western subterranean termites constantly search for new food sources. They are known to enter buildings through cracks in concrete flooring or to travel under parquetry or tile flooring through gaps of less than 1/16" wide.
Where moisture regularly collects inside the wall or other cavities of a building, say from faulty plumbing or broken roof tiles, the Western subterranean termite can develop a subsidiary colony nest which may not require contact with the ground to ensure it's survival.

They build a central colony nest from which they construct underground tunnels that radiate within a 100 yard radius from a central colony nest in search of a timber (cellulose) food source.
termites can build a sub-nest in a wall cavity of a home
The picture left, shows a termite inspector examining an above ground termite subsidiary nest built inside a wall cavity of a home.
Termites often build such nests if moisture is allowed to regularly collects inside the wall cavity, say from leaking pipes, shower recess, faulty plumbing, guttering, broken roof tiles, etc.
Termites - the silent destroyers of timber
Termites travel in humidified mud-shelter tubes or galleries...
The picture on the left shows a mud shelter tube that subterranean termites have constructed over a solid object, in this case, a brick foundation wall in the sub-floor of a cottage.
Subterranean termites travel in these mud shelter tubes as protection from predators, sun-burn, dehydration and to maintain a high humidity environment which is essential for their survival.
Western subterranean termites are highly secretive, preferring to enter a building through areas inaccessible to inspection, such as, through in-fill patios, fire heaths, expansion joints and cracks in concrete slab (on-ground) flooring.
Western subterranean termites can pass through a 1/8" crack or an expansion joint (eating through the rubber compound) between adjoining concrete on ground flooring. They can also travel under parquetry and floor tiles to get to the wall framing timbers.

Only the worker termite caste can digest timber by the use of symbiotic protozoa in their gut. Worker termites feed their partly digested semi-liquid food, regurgitated from their mouth or passing from their anus, to the other termites, a process known as trophallaxis.
Western subterranean termites have a well ordered social system with amazing engineering capabilities and an acute survival instinct; they obtain moisture from the soil and moist decaying timber, and communicate using pheromone signals.
The mutual feeding, constant grooming and close social habits of termites are used to advantage in modern termite control baiting systems.

Certain hi-tech termite baits are now on the market that have a delayed lethal effect on termites which readily pass on the bait to other termites in the central colony nest during the mutual grooming and feeding.
Western subterranean termites need to maintain a high level of humidity and temperature (75 to 95F) in their central colony nest.
Western subterranean termites eat through the centre of susceptible timbers leaving nothing but a thin veneer of timber and/or paint. They will pack mud in cracks and joints in timber to prevent loss of humidity and resultant dehydration.

As noted above, termites constantly groom and feed each other. A valuable technique for the termite controller is to instal and monitor a termite baiting system next to any live activity found in and around the premises where termite foraging is most likely to occur. Subsequent inspections (preferably monthly) may reveal dead or sick worker termites, they change colour to a mottle look, and spread of the termite bait to other termites leading to elimination of the colony.
The termite baits are designed to be non-repellant to the termites and has a unique delayed effect. Time enough to be passed onto the other termites in the colony including the queen, with a sufficient dosage leading to the elimination of the entire colony. This process is explained in detail in the Termite Control section of this website.

If You find these termites do NOT disturb them

Western subterranean termites have acute survival instincts. If they are shaken up or disturbed, the termites often will abandon the associated area and move on to secretly cause damage in other areas in the building. If you find Western subterranean termites in or around your property, it is essential that you do NOT disturb them and promptly arrange for a professional inspection and application of a termite bait to the live termites, if present in abundance.

Subterranean Termites...
Mother Nature's most prolific builders

This is an above-ground termite nest in tropical Australia. In the USA, the destructive subterranean termite species build their nest completely below ground level. A large Western subterranean colony northern California is most often unseen, until a serious problem is encountered.

Modern subterranean termite control methods include termite baiting systems; installation of a treated soil zone around the base of a building; and a range of maintenance measures to make the building less susceptible to infestation.

Learn How to Protect Your Home
Subterranean Termite Control

Western drywood termites

Where do You find them ? Native to the US, the Western drywood termites are found accross the southwestern states, and as far north as Sacramento, with a heavier incidence along the coastal areas.
Drywood termites are considered non-subterranean termites, as they do not live in the ground, require no ground contact, and do not build mud shelter tubes.
Can you bring them into the home in furniture ? YES - Western drywood termites can be transported in infested timber furniture or even picture frames. This termite can survive inside timber with a low moisture content and can branch off to form multiple independent colonies, each containing up to 3,000 termites. They are known to cause extensive damage in buildings.
Are all types of buildings prone ? Western drywood termites more likely to be in a structure made completely of wood with poor workmanship demonstrated by poorly fitted corner joints. The termites typically inter the ends of wood and seldom enter the sides of the section in question.
After the mating flight, they seek cracks or knotholes in nearby wood and chew a small tunnel which they close then excavating a chamber after which they mate.
Swarming drywood termites fly into structures and infest wood directly. When swarming, they often reinfest the same structure. They typically first infest exposed wood such as window/door frames, trim, eaves and attics. They do so by finding a protected crevice or other area, such as the joint between 2 pieces of wood, where shingles/paper overhang timber or moulding, etc., and then attack the wood.
Evidence of infestation include swarmers, shed wings, piles of pellets, termite plugs that seal all openings in infested wood, and surface blisters caused by older, enlarged galleries very close to the wood surface.
Identification: Swarmers are about 1/2'' long including wings, which are approx 3/8" long. The head and pronotum of the swarmer is an orange brown and its abdomen is dark brown - see picture on left.
Key identifier: The front wing has 3 dark, heavily hardened veins in the front portion.
When the colony is about four years old it will, when the time is right, emit hundreds of reproductive swarmers from the nest. It is amazing how all the mature Wester drywood termite colony nests across an entire region, will swarm several times a year, but all at the same time. This is essential to produce new nests, to continue their 250 million year evolution.
Swarming typically takes place about mid-day on sunny, warm (80°F) days, with the peak of the swarm occurring shortly after a sudden rise in temperature. The swarming season usually occurs during September and October. Swarmers usually number in the dozens, occasionally the hundreds. Night swarmers are attracted to lights.

Identification: Soldiers, the forehead of which slopes down gradually from top of head. The head is flattened to slightly rounded in side view. The head is orange to reddish brown with the eye spot whitish - see picture on the left.
Soldiers have mandibles with unequal number of teeth on each member of pair, and antenna with the third segment greatly enlarged and club-like - as indicated by the red arrow in the picture to the left.
The soldiers are the defenders against intruders so if you open up timbers containing a drywood infestation it is the soldiers that first rush out to guard and defend the other colony members.
Although the colony development is slow, severe structural damage may still be caused by the presence of multiple-colonies. Their gallery and tunnel walls are velvety smooth, and no soil is present, unlike subterranean termites.
Another key identifier is that there is no workers present in Western drywood termite infestations; it is the nymphs perform all tasks typically done by workers.

Identification: Timber Damage: Drywood termites eat across the wood grain and create chambers, or galleries connected by tunnels. Although the colony development is slow, severe structural damage may still be caused by the presence of multiple-colonies. Their gallery and tunnel walls are velvety smooth, and no soil is present, unlike subterranean termites. A distinctive indication is no presence of a worker caste and the nymphs perform all tasks typically done by workers.
Identification: Faecal pellets are found throughout their tunnels. Generally, there are faeal pellets present. They are hard, less than 1/32'' long, elongate-oval with rounded ends. One of the unusual distinctive signs of their faecal pellets is that they have 6 concave sides.
Termite Control: Western drywood termites - firstly, obtain a professional termite inspection to determine the extent of an infestation and locations of other possible drywood termite colonies. The results of the inspection will dictate the best treatment options as no single control method is best for all situations.
Where the infestation is severe and extensive - the entire building may need to be fumigated wtth sulfuryl fluoride (Vikane.). Fumigation is a highly technical procedure which involves surrounding the structure with a gas-tight tarpaulin, releasing the gas inside the seal, and aerating the fumigant after a set exposure time. Before fumigation, the homeowner must remove all plants and animals from the house, remove or place food items inside special protective bags, and insure that there is sufficient tarp clearance between sensitive landscaping and exterior walls.
Where the infestation is only loacalised - it may sufficient to effect localise spot tretments of the termute colony. An insecticide is injected into small holes drilled in the timber and into termite galleries. This is the simplest and most direct method of treatment. The amount of drilling required and the effectiveness of this treatment depends on the chemical used and the nature of the infestation.
Links to other websites: Clemson University - Drywood Termites - TAMU University - Termite Control Pesticides - University of Arizona

Pacific dampwood termites

Where do You find them ? The Pacific dampwood termite is the largest and most significant dampwood termite in the United States. They have been found up to 6,000 feet above sea level, but more commonly in the cool and humid coastal areas of northern california.
Where do they build their nests ? Pacific dampwood termites build nests of up to 4,000 in a colony in damp timber. Direct contact with the soil not necessary when if the timber has a high moisture content. pacific dampwood termites are a common problem found in beach homes, in cool, humid regions. The Nevada dampwood termite occurs in the higher, drier mountainous areas of the Sierra where it evident in mountain cabins and other forest structures; it also occurs occasionally along the northern California coast.
How destructive are they ? Pacific dampwood termites will attack most species of timber in buildings throughout its range. Timbers in contact with the soil or structures built near or over water are common targets. Pacific dampwood termites are highly tolerant of moist conditions - sometimes found infesting piers to tidal flooding. A well established colony will produce winged reproductives "swarmers" which may infest nearby timber.
Identification: Swarmers may be seen throughout the year, but most often from August through October. Swarming usually will occur on warm humid evenings just before sunset and are attracted to light. Swarmers are up to 1" in length and of a light to medium brown color with dark brown wings. Nevada dampwood termites are slightly smaller and darker than the Pacific species; reproductives are about 3/4 inch long.
Identification: Soldiers have a large head armed with long black toothed mandibles. The anterior portion is black generally shading to a dark reddish-brown in the posterior position. The abdomen and thorax are a light caramel color, the abdomen varying according to the stomach contents at the time. The largest termites in the United States, soldiers may be very large, reaching 5/8 to 3/4".
Identification: Workers / Nympths are cream-colored with a characteristic spotted abdominal pattern caused by food in their intestines.
Identification: Timber Damage caused by Pacific dampwood termites varies greatly in size and shape and in sound timber may be concentrated upon the softer springwood.
Identification: Faecal pellets are found throughout their tunnels. The pellets are of a similar color as the timber consumed, hard, oval shaped, like a rice grain and about 1/25" long. By contrast, the pellets of the highly destructive drywood termite has a distinct longitudinal ridge - like a pumkin seed in shape. If in doubt contact the experts.
Termite Control: If the infestation is small, destroy accessible nests by removing infested wood. Where practicable, removing excess moisture from the timber will also destroy dampwood termite nests. If colonies are numerous or inaccessible, contact a professional pest controller to carry out a detailed inspection using specialised equipment and provide an estimate and specifications in writing for a termite control program.
Links to other websites: Dampwood Termites - Washington State University - University of California - Canadian Wood Council - Environmental Protection Agency

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