DIY drywood termite treatment is possible for small, accessible infestations, but it comes with a significant limitation: you can only treat what you can see. Drywood termites live entirely inside the wood they eat, and colonies often exist behind drywall or in framing members you can’t inspect. A localized spot treatment might eliminate the visible colony while others continue feeding undetected. With that reality in mind, here’s what actually works for homeowners tackling a confirmed, limited infestation.
Confirm You’re Dealing With Drywood Termites
Before you treat anything, make sure drywood termites are actually the problem. The clearest sign is frass, tiny pellets about the size of a grain of sand that look like sawdust or coffee grounds. Under magnification, each pellet has six concave sides, giving it a distinctive hexagonal shape. The color ranges from light tan to dark brown depending on the type of wood being eaten. You’ll typically find small piles of frass on windowsills, floors, or ledges beneath infested wood, pushed out through tiny openings called kick-out holes that termites use to keep their tunnels clean.
This frass is what separates drywood termites from subterranean termites. Subterranean species build mud tubes from the soil to reach wood, and their waste stays hidden inside those tubes. Drywood termites need no soil contact at all. They enter a structure as winged swarmers during mating season, bore directly into exposed wood, and establish colonies that live entirely within the timber. Their galleries contain no soil. If you’re seeing mud tubes along your foundation, you have subterranean termites, and the treatment approach is completely different.
What DIY Spot Treatment Can and Can’t Do
Spot treatment targets individual colonies you’ve located by their frass, kick-out holes, or damaged wood. It’s a reasonable approach when you’ve found one or two small infestations in accessible areas like exposed attic rafters, window frames, or furniture. The University of California’s Integrated Pest Management program notes that localized treatments make it challenging to ensure complete control because current detection methods can’t reliably determine where colony boundaries end or how many colonies exist inside a structure. If your home has drywall or other coverings concealing the wood framing, there’s always doubt about whether you’ve found everything.
For widespread infestations, or situations where frass keeps appearing in new locations, professional whole-house fumigation (tenting) is the only method that eliminates every colony, including hidden ones. Fumigation typically runs $1,200 to $3,000 or more. Professional spot treatments cost $200 to $700 and include inspection and a written report. DIY spot treatment products run $40 to $150 per application, but that price doesn’t include the professional inspection that helps ensure you’ve identified all active sites.
The Drill-and-Inject Method
The standard DIY approach involves drilling small holes into infested wood to intersect the termite galleries inside, then injecting a treatment product. In professional practice, holes are typically drilled in a diamond pattern with roughly 18 inches of spacing along the same line of wood grain. You’ll need a drill bit slightly larger than your injection nozzle, usually around 3/16 inch.
The goal is to get your treatment product directly into the tunnels where termites are living. When you drill into an active gallery, you’ll often feel the bit break through into a hollow space. Inject about 5 milliliters of product per hole (roughly one teaspoon), enough to coat the gallery walls without flooding. Work methodically along the infested timber, and plug the holes afterward with wood putty or wooden dowels.
Foam Termiticides
Foam products are the most practical option for injection because they expand to fill gallery spaces that liquid alone might not reach. Products containing non-repellent active ingredients are particularly effective for drywood termites because of how these insects behave. They groom each other constantly, share food mouth-to-mouth, and even consume their dead. A non-repellent product doesn’t alert termites to its presence, so they walk through treated surfaces and transfer the chemical to nestmates through all of these social behaviors.
Research on foam formulations tested against drywood termites found that one common non-repellent compound killed all exposed termites within two days on freshly treated wood surfaces. Even on surfaces treated 30 days earlier, it still killed all termites within seven days of exposure. The transfer effect is especially powerful in drywood termite colonies because their closed gallery system means nestmates are in constant contact. Termites that touched treated surfaces or groomed contaminated nestmates passed lethal doses to untreated colony members, even through contact with dead termites alone.
Borate Solutions
Borate-based products (sold as concentrates or powders you mix with water) work as both a treatment and a preventive. A common concentrate is mixed 1:1 with water to create a roughly 23% solution, while powder formulations are typically mixed to 10% or 15% strength. For surface application, the standard rate is about 0.2 gallons per 100 square feet. For injection into drilled holes, about 5 ml per hole is standard.
Borates have a meaningful limitation for spot treatment. Research from the University of California, Riverside found that liquid borate deposits became less effective over time because the solution penetrated into the wood, making it less available on the surface where termites would contact it. This is actually an advantage for prevention, since borate that soaks into wood makes it toxic to any termite that tries to eat it later. But for killing an active colony quickly, borates work more slowly than foam termiticides. If you use a powder-based product at the 10% concentration, plan on applying it twice, letting the first coat dry overnight before the second application.
Orange Oil as a Treatment
Orange oil (d-limonene, extracted from orange rinds) is marketed as a natural drywood termite treatment, and it does have some effect because it can be injected directly into galleries where drywood termites live. However, its track record is underwhelming. A University of California study found that under ideal laboratory conditions, orange oil delivered only a 77% termite mortality rate. In real-world conditions, where you can’t guarantee the oil contacts every termite in a colony, effectiveness is likely lower. Orange oil evaporates relatively quickly and doesn’t transfer between termites the way non-repellent termiticides do, so any insects the product doesn’t touch directly have a good chance of surviving.
If you prefer a lower-toxicity option and have a very small, fully accessible infestation, orange oil is worth trying as a first step. Just know that you may need multiple applications over weeks, and there’s a reasonable chance it won’t eliminate the colony completely.
Safety When Handling Termiticides
Federal regulations require that anyone applying a pesticide wear the protective equipment specified on that product’s label. This isn’t optional. For most termiticide foams and liquid concentrates, expect to need chemical-resistant gloves (not leather or cotton, which absorb pesticides), safety glasses or goggles, long sleeves, and closed-toe shoes. Some products require a respirator, particularly if you’re injecting foam in a confined space like a crawlspace or attic with poor ventilation.
Read the entire product label before you start. It will specify re-entry times for treated areas, which protective equipment is required for your specific use, and first-aid instructions. Keep children and pets away from treatment areas until the product has fully dried or the label’s re-entry interval has passed. Work with adequate ventilation whenever possible, and wash your hands and any exposed skin thoroughly when you’re done.
When DIY Treatment Isn’t Enough
Spot treatment works best as a targeted strike against a colony you’ve positively located in wood you can physically access, drill into, and treat. It falls short in several common situations: when frass piles appear in multiple rooms, when infested wood is hidden behind walls or ceilings, when you’re finding new evidence of activity after an initial treatment, or when the home is in an area with heavy drywood termite pressure and hasn’t been treated structurally before.
Professional no-tent whole-structure treatments, which use methods to treat an entire home without fumigation, typically cost $600 to $1,500 and include warranties of up to three years. If you’ve attempted DIY spot treatment and termite signs return within a few months, that’s a strong signal that hidden colonies remain. At that point, the cost of professional treatment is almost certainly less than the structural damage that continued feeding will cause.