Drywood Termites

Drywood Termite Facts
Drywood termites generally live (feed and nest) in undecayed wood which has a very low moisture content. Unlike subterranean termites, they do not require any contact with the soil in order to live. Thus, they can seriously damage movable wooden objects such as furniture. In the United States, drywood termites are found in a narrow strip from Virginia, south to Florida, along the Gulf of Mexico and from Mexico to northern California on the Pacific coast.

Shading represents areas where drywood termites
are commonly found in the United States

A male and female pair work their way into the wood chosen for the nest. The opening through which they enter the wood is sealed with a plug of brown cement-like material about 1/8-inch in diameter. Behind this plug they excavate a chamber where the queen lays the first eggs. The nymphs which hatch from these eggs perform the work of the colony. Soldiers and reproductives develop from these nymphs. There is no distinct worker caste as in subterranean termites.

During the swarming season, nymphs make round holes 1/16- to 1/8-inch in diameter through which the reproductive forms leave the wood. When swarming is completed, these holes are plugged in the same way as the entrance holes. Damage done by drywood termites is entirely different from that caused by subterranean termites. These termites cut across the grain of the wood, excavating large chambers which are connected by small tunnels.

Typical drywood termite damage.
Note that the galleries are extensive and
that they cut across several annual rings.

The chambers and tunnels being used by the colony are kept clean. Excreta and other debris are stored in unused chambers or cast out through small openings in the wood.

Drywood Termite Fecal Pellets Frass
Excretal pellets (frass) are a distinguishing characteristic of non-subterranean termites. These pellets are hard and have six distinct concave surfaces on the sides; only the ends are rounded. Certain anobiid (powder post) beetles also eject pellets from wood in which they feed. These pellets can easily be distinguished from those of drywood termites because they have rounded, convex surfaces.

Drywood termite fecal pellets "frass".
Often these materials are pushed out of the
galleries through "kickout" holes.

Entrance into wood is usually made from a crack or crevice which the termites can enter before boring into the wood. This may be a crack in the wood itself or may be the joint between two pieces of wood or even the space underneath roofing or sheathing paper.

Because of their ability to live in wood without soil contact, drywood termites are frequently carried in infested furniture and other wooden objects into geographical areas where they are not normally found. For this reason, you should be aware of their habits so as to recognize them when they appear.

Drywood termites may attack wood products of all kinds. Structural timbers and woodwork in buildings, as well as furniture and other wooden objects, may be damaged. Although serious damage is done to buildings and other wood products in some areas of the U.S., these termites are usually less injurious than subterranean termites simply because they are less widespread. In fact while a typical subterranean termite colony can contain more than 500,000 termites, a typical drywood termite colony only contains about 10,000.

The dark western drywood termite, Incisitermes minor (Hagen), is the most destructive drywood termite in this country. It is found from California east to Arizona and Utah. In this area, it causes extensive damage to structures as well as to wooden derricks, piled lumber, furniture and telephone poles. It may infest any dry wooden portions of a structure from the foundation to the roof.

Small swarming flights occur during April through July, frequently after rains. Winged adults are dark brown and about 1/2-inch long. The white, soft-bodied nymphs remain in the galleries and are not seen unless the wood is broken open.

The light western drywood termite, Marginitermes hubbardi, is found from California to Arizona. It is also referred to as the southern drywood termite. This termite is very similar in habits to the western drywood termite but prefers drier conditions and higher temperatures.

Three species of drywood termites are most often found in the southeastern part of the U.S. The light southeastern drywood termite, Incisitermes snyderi (Light), is found from South Carolina to Florida and west to Texas. It is the most injurious species of drywood termite in that area. A second drywood termite, Incisitermes schwartzi (Banks), is a common species in southern Florida occurring as far north as Pensacola. Thirdly, the dark southeastern drywood termite, Kalotermes approximatus (Snyder), occurs along the Gulf Coast west to New Orleans and on the Atlantic Coast north to southern Virginia. It attacks wood in structures, posts and utility poles.

Drywood Termite Treatment Recommendations:
Treatment for control of drywood termites consists of 1) structural fumigation, or 2) localized or spot wood treatment. The localized or spot wood treatment treatment method should only be used in the case of limited infestations. If you are interested in doing it yourself you may want to check out our Do-It-Yourself Drywood Termite Spot Treatment Kit. Extensive infestations should only be controlled by fumigation with Methyl Bromide or Vikane. Both Methyl Bromide and Vikane are restricted use products and cannot be purchased without a Certified Structural Fumigator (or similar) license.

1. Drywood Termite Structural Fumigation
Fumigation is done with sulfuryl fluoride (Vikane) or methyl bromide gas. The entire building is covered tightly with a fumigation cover and the gas is introduced. Vikane has the advantage of rapid and uniform dispersion within the temperature range for climates where drywood termites are found. Such fumigations should be done only by professionals thoroughly trained in the use of gasses. Both Methyl Bromide and Vikane are restricted use products and cannot be purchased without a Certified Structural Fumigator (or similar) license.

2. Drywood Termite Spot Direct Wood Treatment
In order to effectively use a liquid, aerosol or dust formulation, holes are drilled into the infested timbers through the termite galleries or kickout holes, using a 3/16 inch drill bit. Insecticide is then forced through these holes to be dispersed through the galleries. Silica gel such as TriDie is an example of a dust that is used. Dusts should be injected into the termite galleries in small amounts. Too much dust will plug the galleries, and the termites will wall off and isolate these areas.

When treating limited infestations, aerosol's such as Invader HPX and dust formulations such as TriDie are used most often. While there may be a fire hazard created when oil-based materials are used, the injection of a water-based insecticide in a wooden beam may create a favorable site for decay fungi. After an insecticide has been injected into wood, the openings should be plugged with wooden dowels or at the very least sealed with Dap TM.

dampwood termite picture

Dampwood termites
Are controlled by the same methods as drywood termites when they are in wood not in contact with the ground. Where there is ground contact, structural changes to eliminate moisture may be necessary, together with ground treatment as recommended for subterranean termites. However, control consists primarily of eliminating the moisture problem in the wood, often involving replacement of damaged and moist wood.

Powderpost termites
Can be controlled by direct wood treatment or by fumigation, as described for drywood termites.
When drywood or powderpost termites are infesting furniture, insecticides can be injected into their galleries or the furniture can be fumigated. Some professionals control these termites in furniture by using a hypodermic syringe to inject a fumigant into their galleries. This method has the advantage of getting the insecticide inside the wood without making disfiguring holes on the surface of the furniture.

Powderpost and drywood termites infesting furniture can be killed by holding the furniture for 1-1/2 hours in a chamber heated to 150�F, or for four hours in a chamber heated to 140�F. Kilns or special vaults equipped with heating units are used for this purpose. Cold may also be used to control these termites. In northern climates, infested furniture and crates may be moved outdoors, while refrigeration chambers can be used in warmer areas. Exposure at a temperature of 15�F for four days will kill termites in wood. Care must be taken to determine that cold or heat will not damage the article involved.

There are a number of measures that should be considered for prevention of drywood termite infestation. All lumber, especially secondhand lumber, should be carefully inspected for evidence of infestation before being used for construction purposes. Infested lumber should be destroyed. Do not use moist or moisture-damaged wood. In existing buildings, all doors, windows (especially attic windows) and other ventilation openings should be screened with 20-mesh non-corrodible metal wire cloth. Screening will prevent the entrance of winged termites into areas where colonies can be established. Chemically treated wood will also prevent attack. Lumber treated with wood preservatives such as Timbor is also effective. Termite-resistant woods such as cedar, bois d' ark and redwood can also be used.

Recommended Drywood Termite Control Products:

Drywood Termite Spot Treat Kit

Kills - Drywood Termites

Designed For
Homes, Apartments, Condominiums,
Offices, & Small Businesses.
(Not For Food Handling Establishments)

Number of Treatments - 5+***

QTY	PKG	PRODUCT		AMT
1	LB	Timbor (Sodium Borate)	$	17.95
1	CAN	Invader HPX (Baygon)	$	18.95
1	SGL	Centrobulb Mini Duster	$	7.95
		Complete Directions For Use		N/C
		FREE SHIPPING	$	(9.95)
		Individual Item Total Cost	$	54.80
		Your Total Cost	$	39.95
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