New Zealand Native termites
New Zealand currently has three identified native species of termites
Kalotermes brouni (Drywood Termite)
Stolotermes inopinus (Dampwood, or Wet wood Termite)
Stolotermes ruficeps (Dampwood or Wetwood Termite)
All species can be found in the same wood material.
Viable moisture levels vary for them to survive in timber, but I have found that 16% moisture is at the lower end of tolerances for termites in timber.
The native termites live in colonies within the timber, unlike the Australia Subterranean species which occasionally find their way here, and, which live in the soil below the timbers. Therefore trench treatment as carried out on Australian subterranean termites, are ineffective against the NZ Native Termites. New Zealand Termites are far more common in NZ houses, than people are aware. Their damage is often mistaken for borer, or two tooth long horn Beetle damage.
Unlike the Australian Subterranean Termites , the Native Termites do not use earth tubes, relying exclusively on wood tunnels through the timber.
Native timbers used in construction, and some introduced species , such as Cedar and Pine are eaten by these species. Generally, only the sap timber is eaten. Any insect damage in heart timbers is generally confined to Two Toothed Long Horn Beetle which also eats sap timber.
I have noted two examples recently of NZ Termites eating cedar, one in Wadestown and the other in Churton Park.
In the Wellington region, termite signs have been noted recently in the following areas among others , Pukerua Bay, Paremata, Eastbourne, Tawa/Linden, Ngaio, Kelburn, and Karori.
Fecal pellets, slits in timber, and large hollowed out timbers, are often an indication of termites. Elates (King, and Queen Termites) flying during Summer/Autumn, are also good indications, and often the first ones the home owner sees.
The types of structures that termites prefer have a higher moisture level than 16%. These houses include those in damp shady areas, in poor maintenance, and those that have an exterior cladding other than weatherboards, which traps the moisture in the timbers behind. These include, Brick, Plaster, Stone, Stucco, Fibrolite, Concrete and more.
Weatherboards tend not to trap in the moisture, so infestations are less common, but nevertheless do still occur.
Treated timber generally is highly resistant to termites, although some types of treatments over a period of time can loose their resistance to attack.
Exceptions also apply to treated timbers used in areas where they are not intended, e.g Boric treated timbers used in weather exposed areas. .Kiln dried (no treatment) timbers are subject to rot in high moisture areas, and vulnerable to attack
Termites are usually found in wall cavity timbers behind the exterior claddings, or below this in the substructure. As one moves towards the middle of the interior of the house (where it is generally dryer) termite infestations are less common. Areas where the houses show signs of leaking are also prone to attack.
Treating of NZ Termites, involves, treating the timbers they are living in, and the replacement of badly infested timbers with treated timber such as Tanalised Timber like H3.1.
Various termite treatments can be applied directly to the infested timbers and drilling into timbers to treat, where appropriate, will assist.
The use of a Termite Detector (set on high) and a Thermal Camera are also helpful in identifying areas requiring treatment.