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Killing Termite Colonies

Killing termites is dead easy.

They are soft and susceptible to any insecticide; just breaking apart their workings will expose them to the hostile climate and they will die.Killing termite colonies requires some knowledge but not as much skill compared to years past.

If you know for sure exactly where the nest is, you can physically or chemically destroy it. (Details further down this chapter). However, most termites are discovered by accident or as the result of an inspection. And, even if you’ve found hundreds of termites, that is not the same as finding the nest with a queen.

Do-it-yourselfers can purchase a product containing chlorfluazuron.

This bait is available for unrestricted sale to homeowners. It is registered as Colony Killer Termite Bait and can be bought online.

This bait is available for unrestricted sale to homeowners. It is registered as Colony Killer Termite Bait and can be bought online.


This is safe for homeowner use. It can be used to feed termites in monitors set in the ground or to feed termites inside timbers above ground level. This same chemical is used by the majority of the professional service industry but anyone can use it.

This bait is not suitable for controlling Mastotermes, the Great Northern Termite. You can easily identify them: they are 13-15mm long, (that’s more than half an inch) and their distribution is generally North of the Tropic of Capricorn. There is a special section on Mastos further on in this section.

The first termite killer
It is almost 100 years since Bill Flick, a dairy farmer near Byron Bay worked out that termites were social insects like bees which left the hive to bring back honey. He reasoned the termites must be taking food back to the nest, so, if he could puff a light dusting of  arsenic into their working galleries, the workers would not die before they got all the way back because arsenic is a slow-acting poison. The termite workers would then feed the arsenic along with the chewed wood to those in the nest. It worked. At that time if termites got into a house, you repaired it and sold. Bill changed all that. The Flick family built the largest pest control business in Australia.

Bills principle of adding a contaminating chemical to the internal feeding areas is the basis of the modern use of insect growth regulators. The process is most effective, almost foolproof and there are no human toxicity issues at all.

Chlorfluazuron inhibits the production of chitin which is the hard outer shell of insects. It is also known as an Insect Growth Regulator (IGR). The effect is on the nymphs in the nursery area surrounding the queen in a subterranean nest. The nymphs can’t produce the new shell they need to grow to the next stage so they die… thousands of them. The decomposition gases and the resulting fungus makes the nest uninhabitable. The queen dies and the workers and soldiers out in the food areas survive for only a few more weeks.

You can be more confident of a successful kill using the baiting/feeding method than dusting or foaming methods.


As one technician explained it: “If termites are harvesting the bait over a few weeks, they are definitely taking it back to their nest; if you dust or foam and there are no termites in the affected area after a couple of days, it could be they have abandoned the workings because you made it too dusty or too wet or the chemical was too strong.”

A cautionary note:  There can be another reason for empty galleries: if anyone digs outside or in some other way accidentally severs the underground connection tunnel back to the nest, there won’t be any termites visible in the galleries, but it’s not because the nest is dead.

Chlorfluazuron may take longer to kill than the dusts and foams but the nest is just as dead and there is no hazard to people or pets (because we don’t have an outer shell). As reassurance, once termites begin eating the treatment they don’t usually stop until the colony is dead (or you let them run out of the treatment). What you don’t use will keep for years.

Feeding termites in monitors is a mainstream approach used by the industry since 1998 when the IGRs were approved for termite control. Professionals use monitors and baiting because it works.

The three main subterranean termites nest below soil level or in hollow trees. They forage for food through and above the soil. If monitors are placed around buildings, the chances are in the high probability range that scouts will find one. The more monitors you put around, the more likely and the sooner you could expect to intercept a termite colony. These foraging scouts may be from a new colony in its first or second year, but it might also be a decade old colony that is still trying to find a way into your house over or through a degrading chemical barrier.

You can’t make the termites find your monitors. But once they do find them and you know they are there, feeding them is easy… and hard to get wrong.


Buying monitors specifically designed for DIYers

There are two basic designs available: those that are buried in the ground and those that sit up on the surface. In-ground monitors can be placed in lawns or gardens, the on-ground monitors can be placed anywhere but on lawns. This means they can be placed over the cracks in pavers, on concrete paths or slabs over expansion joints against the wall or in sheds. And because they don’t need digging in, there is no battle with tree roots or rocky soil.

The real reason for using monitors is to intercept termite scouts looking for new food sources so which type, in- or on-ground, does the job best?

Every timber that has ever been found and attacked in a building was first found by termite scouts leaving the soil to explore. Except for pole homes, all other home construction types have timber well above and without any connection to the soil — yet termites get to it and begin their attack.

There is also scientific backing. Food attractive to termites was  put in thirty places on the surface of a test area  where termites were plentiful and thirty were buried just below soil level. All thirty on the surface were found before any of the ones below the surface.

If you want to know if there are any termite colonies in the vicinity of your home, it makes sense to put plenty of monitors containing  attractive timber in places where termite scouts go looking. The very high probability is that they will find at least one such  monitor before they find a way to timber up inside the building. Then you can add the chlorfluazuron bait to kill the colony they’ve come from.

Remember we said the more monitors the more likelihood of intercepting scouts? Most homeowners will stop at just a few but mass produced monitors are cheaper and come in cartons of up to 22 such as these TermiTraps.

above ground monitor

The TermiTrap is a UV protected polypropylene box that is guaranteed to stand up to sunlight for at least 10 years. It comes already loaded with Tassie oak timbers which CSIRO declared the most attractive to termites.

Bottom of termite trap

From underneath, the timbers are readily found by foraging termites, or, if placed on a path adjacent to a wall, scouting termites can come up through the expansion joint and through either of the holes in the back. The Trap is about the size of a housebrick.

The open hole in the lid is there to let the humidity in and out. Once termites find this monitor, they will seal around the base and use the timber inside as a scaffold to reach and block this hole so they can control their climate. Its instinctive.

The signal hole is blocked. Termites are busy eating. Push in the mud with your finger and stick a bag of bait on top after aligning the hole in the bag with the now-open signal hole. This provides direct and secure access and the termites begin taking bait rather than timber back to the nest. (Its much easier to harvest).

The foil bag of bait has been activated with water and the label on the underside has been removed opening the access hole. The adhesive stays on the foil on the underside allowing it to stick to the top of the trap. The top label retains its adhesion so you can peel back and check baiting progress then reseal as with a pack of wipes.

This is a DIY Trap was placed on a garden against a wall. The hole in the lid has been filled with termite ‘mud’ mixture to prevent loss of humidity and to exclude ants. The blocked hole is the signal to tell you they’ve arrived and to begin the baiting process.

See the commercial details for the monitors and the chlorfluazuron bait on www.termitetrap.com.au

Termites and temperature
If you check your monitors when they are hot from direct sunlight, you may not see live insects. Checking again when the monitors are shaded may reveal termites working merrily away once more. In-ground monitors that are set right into the ground may fill up with water after rain and it may be several days before termites return. Always confirm live termites before adding the bait.

Feeding termites feeding inside timber is still a matter of following the same principles.

See the uneven surface of the window frame. Termites have eaten it out, in some areas leaving only the paint.

See the uneven surface of the window frame. Termites have eaten it out, in some areas leaving only the paint.

DO NOT waste bait by adding it to timbers that do not contain live termites. The colony is killed only if workers take enough of the bait back to the nest. And they will only take it if they can harvest it, undisturbed, from inside the damaged timber you have found.

Should you find termites in timbers such as the window/door frames, skirting boards inside, or in studs, posts, roof and foundation timbers of any structure, you need to make a small hole into the timber. Ensure you see live termites then add the bag of bait, covering the hole in the timber.

With a pointed knife or small screwdriver, make a hole about as big as your little fingernail. Make sure there are living termites inside.

With a pointed knife or small screwdriver, make a hole about as big as your little fingernail. Make sure there are living termites inside.

Here’s how:

Make an opening in the thinnest area. You can also pick away at any of their ‘mud’ used to fill up joints cracks or splits in the timber. It is only as a last resort you should attempt to open a tunnel on a timber or foundation surface. Phone for advice before you try this… 1800 20 30 20.

Once you have broken through into where it is hollow, wait for a minute or so. If termites are there, the soldiers usually come to guard the opening while workers repair it. You will see their antennae and their heads blocking the hole. If no live termites appear, leave the hole open and come back later or check next day. If they are still using the timber, the hole will be repaired and this confirms they are ready to be fed.


Termite Research - Termites eating termite bait

This shows how termites will come out from the infested timber into a foil bag of bait fixed to the surface.

Check progress by peeling bag the label every three weeks. Multiple bags are usually necessary to kill a big colony. Unopened bags will keep of years.



Killing termites in trees

The termites you may see as dark brown nests high up in a tree are seldom pests of significance. But the main subterranean termites that do that 99% of the damage in Australia, will often nest inside the central ‘pipe’ or hollowed out heart of a mature tree. Mastos, the giant northern termite, don’t always wait for the decay of the pipe. They kill palms and healthy mango trees. (See the special box on Mastos).


If at colonising flight time a termite couple find their way into a hollow tree through maybe a dead/broken-off branch or in through a scar from fire at the base, they could not possibly have better conditions. There’s plenty to eat, moisture and protection. A 50 metre travel to your home would not be out of the question.Termites In A Tree

If you have a large eucalypt, peppercorn or a mature fruit tree nearby, you should check it. Use an 15-20mm auger bit long enough to drill into the centre of the trunk at about shoulder height. Drill at a slight downward angle and when you feel less resistance it will be because you have reached the pipe. As you pull the bit out, look to see if any termites are in the fluting. If not, you could slip in a long thin grass leaf into the drill hole, leave it there for a minute and withdraw it slowly. Termites may be found holding on, ‘attacking’ it. If still no live termites are found, come back in half an hour or next morning; if there is termite life inside, they will be repairing or have repaired the opening using their ‘mud’ mixture. In this situation you don’t need to see live termites.

Here is a treatment process:

Termite Bait Applied Through A Funnel

  1. Re-open the drill hole if it has been repaired
  2. Using a funnel, plastic tube and watering can/bucket, pour at least 30-40 litres of a bifenthrin, permethrin or chlorpyrifos solution down into the tree. These insecticidal concentrations can be purchased from a local hardware store. They may be known by various brand names but the active ingredients are on the front panel of the label. They are poisons and you should read the label for dilution and safety directions.


Killing termites in mounds

Termites that build mounds are subterranean but not included in the termites that do 99% of the $damage to homes. This is because mounds are very visible, not tolerated in home circles and it is very easy to kill these colonies by physically destroying the mound. If you are on an acreage property, make it your rule not to allow any mounds to develop within 200 metres of a building or other structure. Use a crowbar, a pick/mattock to break open the top/sides.


The outer is often very hard. (Years ago, mounds were used for building homestead tennis courts). The less dense and crumbly interior is easier to break. The queen and the nursery are at the base of the mound and if you can’t physically get down there, use 30-40 litres of the dilute insecticidal mixture as above. If you don’t finish off the queen, the colony will be re-built in weeks and you’ll have to try again.


Killing Mastotermes

The Giant Northern Termite Mastotermes darwiniensis destroys houses, trees, vehicle tyres and many other materials, faster than any other termite. They don’t cause the most dollars worth of damage in Australia; that title goes to the Coptos, simply because Coptos distribution covers all the mainland (including where Mastos thrive) and consequently they run up their dollars in the high population cities/suburbs.

Termites - MastotermesIdentification is pretty easy: they are 13-15mm long (that’s more than half an inch). Most other termites are less than 10mm. They don’t build big mounds; those magnetic (north-south) mounds up that way are grass eaters.

Mastos are easy to entice into monitors. Inspect monitors every week or two. If you find live Mastos, the IGR (chlorfluazuron) baits are ineffective, you will need to call in a professional who will probably use a fipronil product. If you are apprehensive of chemicals, do not worry unduly. Fipronil is the chemical in Frontline which is put directly onto the skin of dogs to kill and prevent fleas. So a diluted 3 ml/litre solution of fipronil is even less toxic.



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