Pressure Treatments

• Wood is pressure treated by placing it in a horizontal cylinder that can be up to 150 feet long and 7 feet in diameter. There are two processes used in pressure treating wood: empty cell and full cell.
  
  In the full cell process, a vacuum is drawn on the cylinder after the wood is placed in it. After air has been evacuated from the cylinder, it is filled with a wood preservative and pressure is applied for several hours. At the conclusion of the pressurization period, the preservative is drained from the cylinder and another vacuum is applied. This second vacuum cleans excessive chemical from surfaces of the lumber.
  
  Applying pressure to the treatment cylinder is the first step in the empty cell process. A chemical is applied to the cylinder while it is pressurized. After the cylinder is filled with the chemical, the pressure is increased and held for several hours. At the end of the pressurization period, a vacuum is drawn on the cylinder to remove excessive preservative.
  
  Wood preservatives used in pressure treatment of dimensional lumber include chromated copper arsenate (CCA), ammoniacal coper zinc arsenate (ACZA, disodium octoborate tetrahydrate (DOT) and copper naphthenate. Lumber, pressure treated with one of these compounds, can be purchased at most home centers.
  
  

Trenching and Injection

• Application of insecticides by trenching and injection are effective on subterranean termites that nest in the soil.
  
  In trenching, a ditch is dug completely around the outside of the foundation and deep enough to expose pipe and conduit that run under the slab. The chemical is mixed with water according to the instructions on the product label. The mixed solution is applied to the bottom of the trench while taking extra care to thoroughly treat the foundation around pipe and conduit. To be effective, the chemical must be applied so that it provides a continuous barrier around the foundation.
  
  Injection treatments are made by forcing a chemical solution through holes drilled either into walls or floors of a structure. Usually, upon completion of the treatment, the holes are repaired to restore the original appearance of the structure.
  
  A family of chemicals approved for trenching and injection treatments are the pyrethroids such as permethrin and cypermethrin. These insecticides repel termites so they act as a barrier. Imidacloprid and fipronil are two additional insecticides that control termites, but are not repellents. Termites get the chemical on their bodies and carry it to the colony queen. Once the insecticides kill the queen, the entire colony dies.
  
  Various formulations of borate are available for injection treatments, and many of them can be purchased by individuals. The pyrethroids are also sold across the counter and several pest control companies advertise do-it-yourself products. These products can also be purchased on the web.
  
  

Drywood Termites

• Drywood termites spend their entire life cycles above-ground, so their control methods are entirely different from subterranean termites, which live in the soil and only feed above ground. The most effective treatment of drywood termites is whole-structure fumigation. The entire structure is covered with a plastic tarpaulin, which is sealed at ground level with sand bags. Once the building is completely covered with the tarp, sulfuryl fluoride fumigant is released through a plastic tube into the structure.
  
  Before the structure is covered, all foods must be sealed or removed. All indoor plants, pets and people have to remain out of the building until the tarpaulin is removed following fumigation and aeration is completed. Natural gas or propane/butane must be turned off before fumigation and not turned back on until after aeration and no fumigant is detected within the structure.
  
  This treatment can be performed only by professional applicators.
  
  

Baits

• The most extensively tested bait is the Sentricom Colony Elimination System, which entails a three-step process. A hollow, green plastic cylinder, with slits along the sides for termites to enter, is placed into an augured hole with the cover flush to the soil surface. These cylinders are placed around the outside perimeter of a building's foundation at 10 to 20 foot intervals. Additional stations are installed in suspected termite foraging areas.
  
  Initially, an untreated wooden block is placed in the cylinders to monitor termite activity. When termites start feeding on the blocks, they are removed and replaced with a perforated plastic tube containing the bait. The bait consists of a white paper towel treated with hexaflumuron, a slow-acting termite growth inhibitor. Once termites quit feeding on the bait, it is removed from the cylinders and replaced with untreated wooden blocks so that monitoring can continue.
  
  Recruit AG termite bait is an above-ground station of the Sentricon Termite Colony Elimination System. These bait stations are placed on interior and exterior surfaces of buildings, crawl spaces, fences, utility poles, decks, landscape wood, trees or other areas that could be damaged by termites. Bait stations must be left in place as long as there is termite feeding. If one-third to one-half of the bait is consumed and feeding continues, an additional station should be attached to the one in place.
  
  FirstLine Termite Bait Station is another available system intended for installation on active termite tubes. The station consists of a 4-by-4-by-1-inches plastic housing with slots at the base. It contains corrugated cardboard treated with diflubensuron. These stations are installed on flat surfaces at the leading edge of broken, active termite tubes. Termites rebuild their broken tubes into the bait station and feed on the treated cardboard. New stations need to be installed when bait is depleted.
  
  The Sentricon in-ground system is only available to professional pest control companies. The above ground systems are available to the general public.
  
  

Precautions

• A decision to apply your termite treatments should seriously be considered. Professional applicators receive continuous training on detection of termite infestations, their biology and the newest available methods of treatment. When attempts are made to save a small amount of money by applying termiticides ourselves, we are gambling with the value of our homes and the possibility of expensive repairs due to structural damage caused by termites. Without the proper training, it is easy to apply termite treatments in the wrong places and incorrectly.