Look out of the window and you can see trees bearing obvious signs of termite infestation. Most gardens will have some of the pests chomping away somewhere or other. You can almost guarantee that if the fence looks rotten - termites will be to blame.

Australia's subterranean termite species (white ants) are the most destructive timber pests in the world. In fact it can take "as little as 3 months for a termite colony to severely damage almost all the timber in a home".

A question often raised is whether it is best to destroy the homes they have built in your garden - where at least you know where they are - or whether to leave them alone.

Leaving them alone allows the colony to increase in size. Springtime sees the flying termites milling about in areas with big infestations, as they collect the new queen and fly away to pastures new. Thus are other areas infested.

White termites are sensitive to temperature, humidity and light, and once exposed to the air, will die, but the few you see as you destroy that fence or step are just the tip of the colony. Where you see a dozen, millions will be scuttling around in the underground nest. A single colony can scavenge up to a hextare in search of food.

Termites, needing to keep away from light, build mud tunnels up to 50 meteres long to travel from one place to another. These tunnels are visible - if you look - and can be found running up brick pillars, over concrete slabs, and across your fence. If they travel up the inside of the supporting joists, you are less likely to find them until massive damage is caused. And they can practically demolish a house in 3 to 6 months if undetected.

Once installed, they eat away at the woodwork from the inside - outside all looks well, only a heavy tap on infected timber shows their presence. An experienced termite inspector easily recognising the different sound infected timber makes when knocked.

You can help protect your house by ensuring sufficient ventialtion through the brick piers, and keeping the underside of the house dry. Check regularly for the termite mud tunnels. Don't allow the concrete slab to touch the mud outside, and keep fence posts off the ground by using metal supports, or something similar. And if you are building a new house, consider a steel frame. Remember, prevention is better - and cheaper - than cure.

If in doubt, call in the experts, and have your home treated to prevent infestation.