Drywood Termite Control Services

Drywood termite control encompasses the detection, treatment, and prevention of infestations caused by termite species that colonize dry, sound wood without requiring soil contact or an external moisture source. Unlike subterranean species, drywood termites establish smaller, self-contained colonies directly inside structural lumber, furniture, and framing members, making them a distinct challenge for property owners across the southern and coastal United States. This page covers the classification of drywood termite species, available treatment methods, the regulatory environment governing those treatments, and the decision criteria used to select an appropriate service approach.

Definition and scope

Drywood termites belong primarily to the family Kalotermitidae. The two species most significant to US structural pest control are Incisitermes minor (western drywood termite), prevalent along the Pacific Coast and in the Southwest, and Cryptotermes brevis (West Indian drywood termite), the most widely distributed drywood species globally and a priority concern in Florida and Hawaii. A third notable species, Marginitermes hubbardi, inhabits Arizona and adjacent desert regions.

These termites colonize wood with moisture content as low as 3–12%, which means neither soil contact nor plumbing leaks are prerequisites for infestation — a defining contrast to subterranean termite control services. Colony sizes are characteristically smaller, typically ranging from a few hundred to 2,500–3,000 individuals at maturity, compared to the hundreds of thousands common in subterranean species (University of California Agriculture and Natural Resources, Pest Notes: Drywood Termites).

The geographic scope of drywood termite risk in the US is mapped through the termite risk by US region framework maintained by pest management researchers, with highest pressure in USDA Hardiness Zones 9–13. Termite species identification is a prerequisite for any treatment decision because methods effective against subterranean termites often differ substantially from those optimized for drywood infestations.

Regulatory oversight applies at two levels. The US Environmental Protection Agency registers all termiticide products under the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA), and individual states license applicators through their lead pesticide agency — typically the state Department of Agriculture. Structural fumigation additionally falls under OSHA's respiratory protection standard (29 CFR 1910.134) and, for sulfuryl fluoride fumigants, EPA's tolerance regulations under 40 CFR Part 180.

How it works

Drywood termite control services divide into two operational categories: whole-structure treatments and localized (spot) treatments. The choice between them depends on infestation extent, structural accessibility, and the confirmed species.

Whole-structure treatments expose the entire building to a lethal agent, eliminating all colonies regardless of their precise location:

1. Structural fumigation (tenting) — A sealed tent enclosures the structure, and sulfuryl fluoride gas is introduced at concentrations sufficient to achieve a minimum lethal dosage (expressed in oz·hr/Mcf as required by EPA label). Clearance monitoring with a gas analyzer must confirm safe re-entry levels ≤1 ppm before occupants return. Termite fumigation and tenting services represent the most reliable method for widespread drywood infestations.
2. Heat treatment — Core structural temperatures are elevated to 120–140°F for a sustained dwell time, targeting the thermal death point of termite colonies. No chemical residue is deposited. Heat treatment for termite control is an increasingly selected alternative where fumigant use is restricted.

Localized treatments address accessible, discrete infestation sites:

1. Orange oil (d-limonene) injection — Extracted from orange rinds, d-limonene is injected into infested galleries through drilled access holes. Its efficacy is contact-dependent, limiting it to confirmed and accessible colony locations. Orange oil termite treatment carries a lower regulatory burden but requires accurate infestation mapping.
2. Microwave treatment — Electromagnetic energy heats wood tissue in the treated zone to lethal temperatures without chemicals. Microwave termite treatment is suited to small, surface-accessible infestations.
3. Wood treatment products — Borates (disodium octaborate tetrahydrate) applied to bare or exposed wood create a toxic barrier that disrupts termite gut fauna. Termite wood treatment services using borates are registered under FIFRA and commonly specified in new construction termite protection plans.
4. Desiccant dusts — Silica aerogel or diatomaceous earth dusted into wall voids destroys the insect's cuticle through desiccation.

Common scenarios

Drywood termite control service engagements cluster into four recurring situations:

• Pre-purchase inspection discovery — A termite inspection service ordered during real estate transactions identifies active drywood colonies or evidence such as characteristic hexagonal-faceted frass pellets (see termite frass identification). The extent of the infestation determines whether spot treatment or full fumigation is specified in the wood-destroying organism report.
• Swarm event response — Reproductive alates (swarmers) emerge inside the structure, typically in late summer months in California or in spring in Florida. Swarm identification differentiates Incisitermes minor from flying ant species (see termite swarmers vs. flying ants) and triggers a formal inspection.
• Recurrence after spot treatment — Localized treatments that missed satellite galleries lead to re-emergence, prompting escalation to a whole-structure method. Re-treatment policies and warranty terms govern whether the initial service provider covers this escalation.
• Historic or specialty structures — Buildings with irreplaceable finishes, antique furniture, or moisture-sensitive materials may exclude fumigation or high-heat methods. Termite control for historic structures requires alternative protocols, often with structural engineer coordination.

Decision boundaries

Selecting between treatment approaches follows a structured decision path:

A termite damage assessment establishing infestation severity should precede this decision. The termite infestation severity levels classification used by professional entomologists provides a consistent framework. For properties where cost is a primary constraint, the termite control cost guide outlines typical price ranges by method and square footage.

Licensing requirements for fumigation applicators differ from those for general pest control. Structural fumigation in California, for instance, requires a Branch 2 fumigation license issued by the California Department of Pesticide Regulation. Applicator credentialing requirements by state are catalogued at termite control service licensing requirements. A comprehensive method-by-method comparison — including efficacy data and label restrictions — is available at termite treatment methods comparison.

References

• US EPA — FIFRA (Federal Insecticide, Fungicide, and Rodenticide Act)
• US EPA — Termiticides and Pesticide Registration
• OSHA — Respiratory Protection Standard, 29 CFR 1910.134
• University of California Agriculture and Natural Resources — Pest Notes: Drywood Termites (Publication 7440)
• California Department of Pesticide Regulation — Structural Pest Control Licensing
• USDA Forest Service — Wood Handbook: Wood as an Engineering Material (Chapter on Biological Degradation)
• EPA — 40 CFR Part 180, Tolerance Regulations for Sulfuryl Fluoride