While many homes have been damaged by termites, the ideal situation is to prevent such problems from occurring in the first place. To this end, building guidelines and standards are being improved all the time to ensure new buildings are protected from attack. Many of the same requirements can be implemented to protect older buildings.
All home owners have a responsibility to themselves and their neighbours to avoid making life easy for termites. Many termite problems can be avoided before they start by removing old wood or tree stumps and by being observant. This may not always be possible, so pest controllers can offer advice on how best to protect the property when this is the case. No protective measures are 100% effective, so all owners of homes and businesses should be encouraged to have annual termite inspections.
- Chemical Soil Barriers
One of the most common protective methods is the chemical soil barrier. We looked at this when discussing treatments earlier in this chapter. Typically, the barrier will be established by digging a trench around the foundations of the property, and treating the soil before replacing it. Sometimes high pressure jets are used to inject the chemicals directly into the soil at regular intervals to avoid trenching.
Holes are also drilled in concrete slabs and paths to treat the ground below. Where necessary paving stones will be lifted to allow soil to be treated and then re-laid. The chemical often used to treat the soil is an organophosphate, such as Chlorpyrifos. Even a small building can require the use of a large amount of chemical.
Soil composition, moisture content and other factors affect the efficacy of the chemicals. In soil that is regularly sodden, a chemical barrier may offer only limited or no protection.
The barrier must be 100% complete. If any gaps exist they can be exploited by termites. These breaches may be caused by paths, cables, pipes, tree roots or anything that gives even the smallest opportunity for a termite to pass through.
If applied correctly, chemical barriers are highly effective but many things can reduce its protection. New building work or repairs, cables being laid and other soil disturbance inevitably allow termites to access the home. Even items propped up against the building, if left long enough, can provide a bridge across the barrier.
On its own, a chemical soil barrier can deliver valuable protection for many years but it shouldn’t make the home owner complacent. The best results are achieved when the barrier is used in conjunction with other methods.
- Physical Barriers
Where possible physical barriers can be installed. This may be difficult for existing older buildings but any extensions or outhouses added to these can benefit. The materials recommended are covered in the Building Code of Australia (BCA). These involve metal shielding along walls and at the top of piers. The physical barriers don’t always stop termites but make them visible when they build their mud channels to bridge the barriers.
Concrete slabs laid to Australian Standards will minimize termite intrusion. With access to the building only possible around the edges of the slab, any invasion also becomes visible.
Due its small size and shape, finely divided granite can restrict termite access and is used to fill spaces around pipes and cables that go through concrete slabs. Stainless steel mesh can be placed along the building perimeter or around plumbing and cabling installations. The mesh is so fine that termites cannot pass through.
Bait traps serve two purposes:
- They can be used to monitor the presence of termites.
- They make it possible to poison individual termites which return to the nest and contaminate the colony.
Bait traps vary in size and design but, basically, they are containers placed in the soil with small openings that allow the termites to easily enter and exit. Depending on the species involved different baits may be required. The term ‘bait’ may be misleading as it does not attract the termites but acts as a food source. Different species feed on wood and other materials in various stages of decay and dampness, and this should be taken into consideration when being used as bait.
Aggregation is a term often used in connection with bait traps. The idea is to draw as many termites to the feeding station as possible, to get them to aggregate or gather. If the number is small, then any toxins used on them will have minimal effect on the colony. The greater the aggregation, the more effective the eradication. The size of the traps can play an important part in the success of aggregation. Termites have a control mechanism that determines how many will forage at one spot. This varies by species. If the size of the trap restricts the number of foraging termites, insufficient workers will carry the poison back to the nest.
Initially, the bait is designed to attract the termites not to kill them. Regular inspection of the traps will show the termites’ presence. Only when termites are feeding on the bait is the control agent or poison added.
Bait traps are useful tools in the detection and control of termites but they have drawbacks. Unless enough traps are put in position and, in the correct places, termites may simply bypass them, unaware of their existence.
Some species of termite are less sensitive to the poisons used in traps than others. This ability and their tendency to avoid any area that has been regularly tampered with, make traps good but not without their shortcomings.
Coptotermes acinaciformis will often be found in the traps and take the bait back to its nest but its close relative, C. frenchi, will rarely do so. Schedorhinotermes species often avoid traps due to the regular disturbance needed to check them. Normal bait poisons are ineffective against Mastotermes. A large colony of any species will need a larger dose of poison than a small one but simply increasing the amount may scare off the termites.
Due to the different habits of each species and the varying nature of the colonies, the size and type of traps used, as well as the bait and the chemicals involved will need to be given careful thought.
Naturally termite-resistant timber or wood that has been treated against termites can impede an attack. The recommended timber and timber treatments are covered in AS 3660.
A common feature of most barriers, either physical or chemical, is that termites become visible when they try to avoid them. This reinforces the need for an annual inspection. It also demonstrates that the threat from termites is a never-ending one. Barriers are good but not perfect. The home owner should be observant, regularly looking for any tell-tale signs of the presence of termites – droppings, mud channels, wood damage, etc.
Monitoring stations positioned around the grounds of the property work exactly the same as bait traps. Their purpose is not to kill termites but check for their presence. Monitoring stations typically have transparent plastic lids that make it easy to see inside, minimizing disturbance. A monthly check of these stations should only take a few minutes but will alert the home owner if pests have arrived.