Detection and Eradication of Termite Nests starts first with the identification of the termite that is definitely the first thing that you do as there are approximately 30 kinds of termites in the ACT region.
Nasutitermes exitiosus is almost invariably a mound builder in Canberra. If N. exitiosus is found it is likely there is a mound within 30-50 metres of the infested area, often in adjacent bushland. Nests can be destroyed by physically breaking up the nest and spraying with a registered insecticide and filling the cavity with clean soil. Coptotermes frenchi, Porotermes adamsoni and occasionally C. acinaciformis mostly nest in old eucalypt tree trunks.
If these termites are detected, all large eucalypt trees (trunks greater than 30 cm in basal diameter) or stumps within 60 metres should be checked. One indication of termite activity within trees is the presence of hollow broken branches. This is only indicative and a more reliable method is to test by drilling the tree. A drill auger (not larger than 19 mm diameter) should be used to bore holes towards the centre of the tree. If termites are present the centre will be hollow or filled with ‘mudguts’ and the auger will suddenly penetrate the tree easily. A thermometer may be used to determine if the nest has been located. Nests are a constant temperature of 300C.
To determine if termites are still active within the tree, termites may appear on the auger or a length of dowel or long piece of grass can be inserted into the auger hole and left in place for several days. The dowel or grass is then withdrawn and checked for termites.
Trees found to harbour termites should be treated with insecticidal emulsion administered through the auger hole or with arsenic trioxide (only by licensed operator) or other registered products. All auger holes drilled in trees on public land (including trees inspected and treated for termites) must be plugged with a non-toxic acrylic caulking compound, such as bathroom sealant or anti-fungal agents specifically designed for this purpose.
Do not use dead wood such as dowelling as it prevents the tree from healing or silicon sealants as they contain harmful solvents which can damage the tree. A drop-off in termite activity in the feeding area should occur within a few months of nest treatment. If termites still persist for twelve months or more alternate treatment such dusting with arsenic trioxide or the installation of barriers will be necessary.
Installation of barriers
The installation of barriers, either physical or chemical, prevents termites from entering buildings. Houses with suspended floors can have termite caps fitted to piers and shields fitted on foundation walls. Also the soil under and/or around the house can be treated with insecticide. Termite caps should be checked regularly (every six months) for the presence of galleries around the caps. If galleries are present termites should be identified leaving the infested area as undisturbed as possible. Once termites are identified, a strategy for control can be developed usually in the following priority order:
- detect and destroy nest;
- apply registered termiticide (by a licensed operator) to the infected area, with minimal disturbance, to kill a distant colony that cannot be located; and
- installation of barriers.
It is rarely feasible to fit termite caps and shields to an existing building, but installation of a chemical barrier is reasonably straight forward if the building has a suspended floor with adequate clearance. A 30 cm strip of soil 30 cm deep around all walls, piers and pipes should be treated with insecticidal emulsion. If there is insufficient space to work under a building floor there are two main alternatives:
- Spraying with insecticide. The disadvantage is that spraying contaminates the whole under floor area and dosages at vulnerable points cannot be controlled closely.
- Lift floorboards and treat around exposed walls and piers. This may be a feasible option where flooring has been damaged and needs replacing.