Drywood Termites, Dampwood Termites, and other Wood Destroying Insects
Unlike the Subterranean termite, dry wood termites do not require any contact with the soil. They live in undecayed wood with a low moisture content.
Drywood termites are in distinct forms or castes - reproductives, workers, and soldiers. Each performs a separate biological function. Only the reproductive dry wood termites are winged (4 wings).
Their are no workers in the dry wood termite group - instead the young reproductives and soldiers serve as workers until they mature. The vast majority in the dry wood termite colony is the worker caste and the workers, and the reproductives have chewing mouthparts especially adapted for chewing wood. In dry wood termites, it is the workers who do the wide-spread destruction. The soldiers have powerful mandibles to attack their enemies (usually ants).
Male and Female reproductives up to 1/2 inch long. Drywood termites have bodies soft and cylindrical in shape, usually pale brown in color; six-legged; they have compound eyes and chewing type mouthparts. During the winged stage, there are four equal size wings that extend longer than the body by 1/8-1/4 inch. Drywood Termites - Soldier 3/8 inch;
Wood and occasionally other cellulose materials. They eat wood in houses, utility poles, furniture and dying trees. They can not digest the cellulose directly. They have other microorganisms (protozoans and bacteria) in their stomachs that help break down the cellulose that then can be digested by their metabolism.
Drywood termites live in small social colonies in dry wood. They mate and fly to new dry wood areas; enter a small hole in the wood and start to form a colony. In the first year, colony size may be only around 50. After four years, there may be as many as 700 individual dry wood termites in one colony. At this time, the colony may swarm to start the cycle over again. After 15 years, the dry wood termite colony will have grown to approximately 3,000 individuals. Drywood termites do not need a source of water and live off of the water that is produced from the digestion of the cellulose.
Drywood termites infest dry, undecayed wood. This includes structural lumber as well as dead limbs of native trees and shade and orchard trees, utility poles, posts, and lumber in storage.
The Drywood termites variety has a low moisture requirement and can tolerate dry conditions for prolonged periods. They remain entirely above ground and do not connect their nests to the soil. Piles of their fecal pellets, which are distinctive in appearance, may be a clue to their presence.
From these areas, winged reproductives seasonally migrate to nearby buildings and other structures usually on sunny days during fall months.
Drywood termites are usually found in the humid coastal and subtropical regions. These include California, Hawaii, Florida, Arizona, South and North Carolina, New Mexico, Texas, Alabama, Mississippi, Louisiana and Puerto Rico). They usually infest attic spaces or exterior wood members exposed to them when they swarm in early spring or summer.
Typical signs of drywood termites infestation include:
- Shed wings
- Ejected pellets
- Galleries inside wood are typical signs of a dry wood termite infestation.
- Swarming ants are many times confused with dry wood termites, but their differences are easy to recognize. At: Differences between ants and termites , you will find a list and chart showing you the difference.
- Piles of their fecal pellets, which are distinctive in appearance, may be a clue to their presence. The fecal pellets of dry wood and damp woody termites
Fecal pellets of damp wood and dry wood termites are elongate (about 0.03 inch long) with rounded ends and have six flattened or roundly depressed surfaces separated by six longitudinal ridges.
Recommendations for treatment with drywood termites:
PO Treatment for drywood termites consists of:
- Structural fumigation: A certified pest control operator provides structu . The entire building is covered tightly with a fumigation cover and a sulfuryl fluoride(Vikane), or methyl bromide gas is fumigated.
- Direct Wood Treatment (Spot treatments:
To prepare for use of a liquid, aerosol, or dust formulation, drill hol into the infested timbers through the termite galleries. Use a 1/2 " drill in larger timbers and smaller drills elsewhere. Termite insecticide is dispersed through the galleries thru these holes. Drione Dust is labeled for such use. Dust should be injected in the galleries in small amounts.
Too much dust would clog the galleries, and the termites will wall off and isolate these areas.
When treating limited infestations, aerosols like Phantom Aerosol and Drione dust may be used. If you inject a water-based insecticide in a wooden beam, it may produce a favorable site for decay fungi. From: UC Pest Management Guidelines - Drywood Termites, you will find information on detection, whole structure vs. spot treatments, eliminating existing infestations, whole structure treatments and long-term preventive treatments.
Because of their ability to live in wood without soil contact, non subterranean termites, like the dry wood termite, powder post beetles, or damp wood termites, are frequently carried in infested furniture and other wooden objects into geographical areas where they are not normally found.
As the name implies, dry wood termites establish in dry, sound wood that may have as little as 3 percent moisture content. Drywood termites are not dependent upon a constant moisture supply as are the subterranean termite types.
One of the common symptoms of dry wood termites attack is the accumulation of tiny, straw-colored fecal pellets inside or beneath infested furniture. These pellets shift from small holes in the surface of infested wood or are pushed out through small round openings maintained by the dry wood termites for this purpose. The hard fecal pellets have six distinct, concave surfaces. The presence of pellets does not prove damaged wood is currently infested, as pellets continue to sift from furniture for many years after dry wood termites are controlled or die. However, large, consistent accumulations of pellets are a convincing sign the termites are still active.
If the furniture is untreated, use Timbor or Boracare.
Spray and allow it to penetrate the wood. It will last the life of the wood and kill the active beetles. If the wood is painted or varnished, you will need to strip the finish to use either one of these products. Drywood Termites and Powder post beetles can be killed by either extreme heating or freezing. It would need 1.5 hours in a heated chamber of 150°F or 4 hours in a chamber of 140°F. You can also use freezing temperatures to kill these insects. Exposure to -4°Fdegrees F for seven days will kill them. You will need to take care that either extreme of temperature would not damage the article.
Winged damp wood termite
Dampwood termites don't require contact with the soil to obtain moisture, but wood with a high degree of moisture is needed. They are usually associated with wood decay. Because of their high moisture requirements, they most often are found in cool, humid areas along the coast.
Pacific damp wood termites (at times called a "rotten wood termite") is a major pest at low altitudes along the coastal areas of California, Washington and Oregon.
Dampwood termites winged reproductives are dark brown with brown wings. Soldiers have a flattened brown or yellowish brown head with elongated black or dark brown mandibles. Nymphs are cream-colored with a characteristic spotted abdominal pattern caused by food in their intestines.
Dampwood termites nest in wood buried in the ground. In nature, they are commonly found in tree stumps and fallen tree branches. In your home, the most likely areas to find them would be an older wood deck, leaky roof eaves, leaky showers or tubs, or substructures with inadequate ventilation or plumbing leaks.
The Dampwood termite is much larger than the subterranean and dry wood termites, measuring in at 3/8 to 3/4 of an inch. They can swarm periodically throughout the year, and it is common to see the swarming reproductives caught in spider webs next to exterior lights since they are instinctively attracted to light.
The work of the colony is done by the immature soldiers or reproductives, there is no worker caste. Dampwood termites swarms are small.
They produce a fecal pellet similar to dry wood termite, but it is slightly larger and has a more irregular shape. Damage in wood can be identified by a velvety appearance in the galleries.
Dampwood termites produce distinctive fecal pellets that are rounded at both ends, elongate, but lacking clear longitudinal ridges common to dry wood termite pellets; flattened sides are noticeable.
The Nevada damp wood termites are slightly smaller and darker than the Pacific species; reproductives are about 3/4 inch long.
The Nevada damp wood termite occurs in the higher, drier mountainous areas of the Sierras where it is an occasional pest in mountain cabins and other forest structures; it also occurs along the northern California coast. It differs from the Pacific damp wood in being subterranean in "habit". It attacks only moist wood. This termite is of horticultural importance because it frequently attacks the underground parts on shrubs andd young trees. It often occurs in citrus groves. It is also found in fence posts, baseboards and door frames of buildings. Flights occur in July and August in evenings after rains.
The Florida damp wood termite is found in the extreme southeastern counties of Florida and the Keys. It lives naturally in damp( but solid) logs near salt water and is a common pest of buildings in this limited area. It is not subterranean by nature, although it may enter logs beneath the soil.
Control of Dampwood Termites:
Chemical treatment may be not necessary for the control of damp wood termites. Since the damp wood termite requires wood with a high moisture content, correction of the moisture source is necessary. This normally means replacing the existing infested and saturated wood in conjunction with elimination of the moisture source.
Common correction methods:
- Increase the ventilation in the affected area, reducing the moisture and repair leaky showers and plumbing.
- Make sure you have proper drainage.
- Construction needs to be designed to avoid contact of wood and soil.
- If the damp wood is not accessible to be removed, treatment of the soil with an effective insecticide or termite baiting systems would be necessary.
In this section we will discuss four types of Powderpost beetles in four families: Lyctidae, Bostrichidae, Anobiidae, and Cerambycidae. Adults do little damage; it is the larvae that do the major part of the damage.They go through a complete metamorphosis: adults, eggs, larvae, and pupae.
True Powderpost Beetles(Lyctidae):
The adults are very small, less than 1/4" in size. They are flattened and reddish-brown to black in color. Larvae are white, cream colored, c shaped with dark brown heads. Larvae create tunnels in the wood and become pupae. As adults, they bore out through the wood, pushing a fine powdery dust out.The shape of their holes are round , about 1/32-1/16 pinholes.
They attack hardwoods depositing their eggs. They can attack bamboo(technically a grass), but because of the large pores they will attack. Their diet is starch, sugar and protein in the sapwood of hardwoods Wood that is less than 6% moisture content is seldom attacked.The life cycle averages one year to complete.This wood-boring beetle is the most widespread in the United States. Many times infestations are built into structures from infested lumber.They can reinfest.
Lycid damage is characterized by:
- Presence of extremely fine, flour-like powder falling from the surface holes.
- The frass left by other wood borers usually contains pellets has a course texture and a tendency to stick together.
- When inspecting damage, be sure to distinguish old damage from active beetle infestations.
- Recently formed holes, and frass(sawdust like) are light in color and clear in appearance; old holes and frass are dark in color.
False Powderpost Beetle (Bostrichidae)
False Powderpost Beetles are larger than other families of powderpost beetles, so their exit holes are larger. These holes do not contain frass, but the galleries do. The frass is tightly packed, tends to stick together and is meal like( contains no pellets)
The adults are 1/8-to 1-inch long, cylindrical, and reddish brown to black. The adults bore into the wood to lay eggs, leaving a hole larger that 1/8 inch, usually in wood less than ten years old.
The larvae are curved and wrinkled. Their diet is dependent on the starch in the wood, they are more common in softwood , but can attack hardwoods. They require 6-30% moisture content in the wood and complete the average life cycle in one year.
Most of the hardwoods attacked are not those commonly found used for interior floors, woodwork or trim. Most of this species does not reinfest wood after it is seasoned, so the damage is limited to that inflicted by one generation. However, the speed of the damage can be considerable. Most of the time they do not reinfest wood after it has been seasoned. They are often found in oak, firewood, and furniture.
Anobiid Powderpost Beetle (Anobiidae)- Furniture and Deathwatch Beetles
The furniture beetle is found mostly in the eastern half of the United States, and it infests structural timbers as well. The Death-watch beetle is found throughout the United States. It attacks building timbers in poorly ventilated areas where moisture tends to collect.
The name"Death watch" comes from the ticking sound that the adult makes inside infested wood that is audible during a still night. It is a mating call.
The insect is a common pest in the southeastern United States in crawl space timbers. Infestations can become so severe, that loss of structural strength to sills, joists, and subflooring occurs.
The Adults are 1/8-1/4 inch long. They are red to dark brown in color, and their shaped is usually oval. The adults lay their eggs in the cracks and crevices of the seasoned wood. As soon as they hatch, larvae burrow into the wood where they live and tunnel for a year or more.
The larvae form tunnels in both softwoods and hardwoods They require 13-30% moisture content. The larvae are slightly curved and wrinkled, with tiny hairs on the body.
Their holes are round 1/16-1/8 inches. They can digest cellulose from the wood. They are inclined to the softwoods , for this reason, they are common in crawl spaces and basements , infesting the pine used as framing lumber.
The powder outside the holes (frass) is fine to coarse, many times with small pellets. The life cycle averages 1-3 years.
They commonly reinfest crawl space areas that are poorly ventilated, and humidity is absorbed in the wood.
Old House Borer (from the family Cerambycidae)
The Old House Borer is one of the most common from this family, with it's larvae hollowing out galleries in seasoned softwood (pine). It is found in older buildings but is more frequent in newer buildings, (in houses less than ten years old). The adults are brownish-black to black, slightly flattened and about 3/4-1 inch long. The average life cycle is usually one to three years, but can take up to twelve years if nutritional and environmental conditions are unfavorable. Because of the long life cycle, reinfesting the wood it may take years before you see any structural damage.
The exit holes are about 1/4-3/8-inch in diameter, but the damage may have occurred for several years before spotting such holes. They can digest cellulose.
When the wood has been infested with fungi, the larval development is faster. Their powder (frass) in the tunnels are like sawdust , tightly packed.
Inspection for Wood Boring Beetles
- Inspect periodically all exposed wood surfaces and probe them for evidence of internal damage.
- Evidence of attack is more common in attics, crawl spaces, unfinished basements and storage areas.
- To be certain that the infestation is active(not old damage or old frass), there should be fresh frass the color of newly sawed wood, or live larvae or adults in the wood.
Control and Recommendations:
- The first thing to do is reduce the moisture content, to a proper ventilation to less than 20%.Moisture meters can be used to determine the moisture level in the wood. Central heat, vapor barriers, and good ventilation can help control moisture.
- If practical..remove infested wood. If not,use residaul borate insecticides.
- Recommended products are two borate insecticides:
Timbor is a powder that mixes with water. One and 1/2 lbs mixed with one gallon of water and sprayed to the surface area of in infestation. When sprayed it penetrates the entire wood, where it will remain for several years. An alternative to Timbor is Boracare
Boracare: Boracare is a liquid borate that penetrates faster initially than the Timbor for first few hours but is equal after that. Timbor is considerabley cheaper per gallon use.
Carpenter ants are quite large, from 1/4 o 3/8" long; dark brown to black, but some may have a red or yellowish coloration. The usual carpenter ant is large and black, but you can have the Florida Carpenter Ant, which is smaller with a range in colors; yellow, red-brown or black.
For more information: Carpenter Ants
They eat a variety of plant and animal foods and sweets. These ants will also feed on other insects. They do not digest wood.
Being social insects,they have different forms of "castes" in their colonies. Mature colonies have winged a nd wingless queens, winged males, two sizes of wingless workers, and immature stages(eggs, larvae, and pupae).
- They swarm and mate during the springtime.
- Swarming generally occurs after three-six years,when a colony contains 3,000 or more ants.
- A single queen starts a new colony.
- Damage can occur before a homeowner is aware of the presence of carpenter ants. It takes a while to build up the colony in population before you may take notice of foraging ants or swarmers.
- Carpenter ant colonies inside homes may release swarms indoors.
- Carpenter ants in the house during the winter months or winged carpenter ants indoors at any time of year is a sign that they have a nest somewhere in the house.
- If it is just a few workers, seen during the summer months, more likely they are simply foraging from the outside; entering and exiting.
A carpenter ant colony may contain a main nest and one or more"satellite" nests. The main nest contains the queen, eggs and larvae, and workers. Ants in these "satellite" nests are the ones that normally do structural damage to homes.
During the winter months, the ones outside are inactive. The indoor nest can remain active, but at a reduced rate.
They are nocturnal. There activity peaks between 8:00 p.m. and 4 a.m.Their ideal temperature for habitation is between 71 degrees to 74 degrees F. It would be advantageous to inspect at these times and temperature conditions.
- They usually nest outside in moist wood or partially decayed wood in that they prefer the "softened wood" to hollow out their nests called "galleries".
- These galleries are quite clean and have a sandpaper appearance.
- (Termite galleries are rough looking in comparison.)
- Wood, which has been damaged by carpenter ants contains no mud-like material, as is the case with termites.
- Nests are especially common in such places as moist, hollow spaces, like the wall void behind dishwashers.
- Nests are usually found in areas where water leakage could occur, around bathtubs, sinks, roof leaks, poorly flashed chimneys, or poorly sealed windows or door frames.
- Outdoor nest can occur in stumps, hollow logs, fence posts or in dead portions of standing trees. However cracks and crevices may be used to start nests in sound wood.
They may establish nests in some different locations. It is important to understand that you can have both inside and outside nests. They construct two different kinds of nests: parent colonies which, when mature, contain an egg-laying queen, brood and 2000 or more worker ants, and satellite colonies which may have large numbers of worker ants, but no queen, eggs or larvae. The carpenter ants inside a home may have originated from the parent nests located outdoors in a tree stump, timber or woodpile for example. They may also originate from one or more satellite nests hidden behind a wall in the kitchen or bathroom, or perhaps from wood dampened by a roof leak in the attic. Although large colonies can cause structural damage, the damage is not normally as serious as termite damage.
How to detect galleries:
- Many times you can see "sawdust" near these carpener ant galleries.
- This "sawdust" or "frass", are shredded fragments of wood that has been ejected from the galleries. This is a good indication that a nest is nearby. But sometimes this evidence is not seen, taking a screwdriver, probing the wood may reveal the excavated galleries.
- Also, you could take the blunt end of the screwdriver to tap along baseboards, and other wood surfaces listening for the hollow sound of damaged wood.
- If a nest is nearby, many times the carpenter ants will respond by making a "rustling" sound within the nest, similar to crinkling of cellophane.
Foraging Carpenter Ants from the outside:
Many times the ones that you see inside your home are simply foraging for food, you won't see large numbers typically.
Foraging ants can travel 100 yards from a nest to food and can be simply found wandering throughout your house.
However, there can be indoor nest found in hollow doors, window sills, behind baseboards, or other natural hollow areas.
Their damage usually indicates water damage and wood decay.
Recommended products and treatments
PERIMETER TREATMENT, with an non repellent residual insecticide such as
- Taurus SC or FUSE would be a wise choice, stopping any new populations and other invading pests such as roaches, spiders, etc. You may spray Taurus twice a year, and Fuse may be sprayed up to four times a year. Spray around the foundation of the structure, up around 1-2 feet (depending on which insecticide you choose) as well as around the ground floor doors and windows. Both these products are non-repellent insecticides. These insecticides can not be detected by the ants, so they can not avoid it as they cross over it.
- Using ant bait is another alternative. First inspect the ant activity then place a sugar based bait, like Optigard and a protein based bait like Advance 375 A along their trails. The foraging ants will find the baits and feed it to the colonies; distributing the bait to the rest of the colony. You may combine a non-repellent insecticide with baits in the same location.
Ant trails and baiting
Inspect wooden structures associated with high moisture, where there may be water damage-producing softened wood. They like windows and door frames and sills, as well as tub enclosure walls, and kitchen and bath plumbing walls. Many times you can observe carpenter ants more after sunset, when there activity is increased, particularly in the spring and summer months. You may want to use a flashlight to observe any obvious trails and patterns.
Bait in these areas.
Possible steps for Carpenter Ant prevention:
Correct moisture problems:, roof leaks, plumbing leaks. Cut back tree limbs or branches that could serve as a bridge to your structure. Seal cracks and openings around the foundation, especially where utility pipes and wires enter from the outside. Firewood needs to be stacked away from the house, elevated off the ground if possible. They love to nest in firewood.