Drywood termites are oftentimes a big problem, especially in coastal regions that are in tropical or semi-tropical zones. They seem to prefer coastal climates that are not too wet and yet breezy at the same time, and are the second most destructive termite type after subterranean termites. They nest inside wood that is often a part of a building’s foundation or structure. Or else, they nest inside wooden furniture and this often damages the furniture beyond repair. Their colonies are small, usually less than 1000 individuals, and scattered, making locating their nests quite hard.
Usually the only times they are detected is when they swarm, or when they eject their feces in the form of small pellets that can be seen on the floor. Species belonging to Cryptotermes, Incisitermes, and Kalotermes are some of the more common ones seen infesting wood in houses.
The fecal pellets are merely an indication that drywood termites once existed in the wood nearby, but not necessarily proof that they still exist there (the colony may have died out). The main way to be sure is if the fecal pellets continue to increase in number or after wiping away all the previous old ones, new pellets continue to appear. This would indicate an active colony.
Learn more about the signs of drywood termites here.
Preventing Drywood Termite Infestations
Prevention is always better than cure, so the saying goes. Well how do you prevent drywood termite infestations in the first place? A bit different from subterranean termites because they don’t travel through soil, drywood termite prevention mainly focuses on treating wood either pre-construction or post-construction, by applying chemicals, pressure treatment, or installing barriers, all of which have their pros and cons.
Chemical treatment may wear or leach off after some years, and if they are applied unevenly due to inadequate drilling, protection is of course not guaranteed. Last but not least, these chemicals used to treat the wood may also be toxic, so make sure to discuss thoroughly with the pest control company if you are going for preventive measures.
Drywood Termite Treatment Methods
Once it has been determined that an active drywood termite infestation is occurring, treatment is often best left in the hands of a reliable termite control service, due to the difficulty in locating and eradicating them. Treatment methods are basically of two forms:
- Localized treatment
- Whole-structure/building treatment
Maybe you wonder what the differences between these two methods are.
Localized treatment is much cheaper than whole-structure treatment, but is limited to the particular areas of application. In military speak, it is like “precision bombing”, so it’s essential to get the accuracy right for the exact location of the colony. Whole-structure treatments would be much more costly, and be likened to “carpet bombing”; crude but quite effective nonetheless.
Localized treatments include the usage of chemicals injected, sprayed, or pumped into the wood, or more rarely, the use of heat, microwaves, or electrocution. Chemicals need not be toxic, and can comprise natural substances like orange oil or neem tree oil.
A relatively “safer” chemical used these days for localized treatment is Chlorantraniliprole, of which, a commercial brand called Altriset which contains Chlorantraniliprole, has proven quite effective. Chlorantraniliprole is quite new, and was developed by DuPont. In various tests it has been found to be only minimally toxic for mammals, while still being highly toxic towards invertebrates like termites and other insects, thus making it an increasingly popular choice for termite control.
The efficacy of all such localized treatments all depends on whether the nest location is accurately detected. If yes, the treatment will certainly be successful in killing the termites exposed to the treatment agent used. But if not, then it’s just a waste of time and money, even if a small number of termites did get eliminated by the treatment. Also, the wooden structures will get damaged due to drilling or excessive heat/microwaves,electric current/etc. applied.
Whole-structure treatment involves treating the entire building with either heat or fumigation. Fumigation (or tenting) is often effective but costly, and you would need to vacate the building along with all your pets and plants for at least several days. The chemical sulfuryl fluoride is sprayed into the building, and this is effective in simultaneously getting rid of all infestations of drywood termites lurking within the building.
Heat treatment involves heating all the wooden structures in the building to temperatures above 50°C by pumping in hot air and maintaining the temperature for more than 30 minutes. Heat treatment is less of an inconvenience compared to fumigation; you just need to vacate the building for a few hours. But its drawback is that the heat often is not dispersed evenly, and some areas of wood behind tiles or concrete may not be heated sufficiently. Also, the heat may damage some of the less heat resistant components of the building, such as the outer rubber casing of wiring.