pest control – termites · termites are often wrongly called ‘white ants’. this term should...

3/16/2016 Pest control – termites health.vic

https://www2.health.vic.gov.au/publichealth/environmentalhealth/pesticideuseandpestcontrol/commonpestsinvictoria/termitespestcontrol 1/8

Pest control – termites

Key messages

Termites belong to the insect order Isoptera, meaning ‘equal wings’.

The digestive system of termites contains a variety of microorganisms to assist in the digestion of theplant fibre cellulose.

There are more than 350 species of termites in Australia, and few are considered pests. Onlyapproximately 20 species cause damage to buildings. In Victoria, there are five species that causedamage to buildings and wooden structures.

Termites play important ecological roles by providing nest holes for lizards, birds and possums,breaking down organic matter, returning nutrients to soil and assisting with soil aeration.

Termites are often wrongly called ‘white ants’. This term should not be used because termites areneither white nor ants.

Termite coloniesTermites live and work together in nests or colonies. Members of the colony take different forms or‘castes’. These include:

AlatesAlates, meaning ‘winged ones’, are the true adult termites.

They have eyes, wings, darker colouring and are fertile.

Their wings are equal size and shape and twice the length of their body. They shed after the colonisingflight is made. Shed wings are a good indication of termite presence.

Reproductives

Termites need food (wood) and water to stay alive. By removing access to these needs,homeowners can reduce the risk of termite attack.Physical barriers can be built into new homes to prevent termites reaching wood structures.Additional methods of termite control include baiting, dusting and creating chemical barriersaround the building.Termites are often wrongly called ‘white ants’. This term should not be used because termitesare neither white nor ants.



These are the sexual forms of the colony including future kings and queens of colonies yet to beestablished.

The reproductive’s live in a central chamber in the nest where a female, or ‘queen’, will lay manythousands of eggs each year over her life span of approximately 10 years. Male, or ‘kings’, areresponsible for fertilising the queens. Multiple reproductives are commonly observed.

The young termites develop in the colony by shedding cuticles at the end of each growth stage,gradually changing until they reach the worker, soldier or adult (winged form). If queens die, somesupplementary reproductives may carry on the colony as neotenics.

Reproductives are generally darker than workers and soldiers. They have functional eyes and theirmore robust skin (cuticle) is able to resist the outside environment. After flight, unlike other insects, thedeciduous wings of termites are discarded and piles of shed wings are a good clue to termiteinfestations.

SoldiersSoldiers have darker, larger heads than the other castes. They are blind, wingless, and haveundeveloped reproductive organs.

Soldiers are tougher than the other castes and take longer to die from most toxins, exposure, orstarvation. It is their role to defend the colony, if disturbed, while the damage is repaired by theworkers.

Soldiers exist in different forms. Most species have soldiers, with welldeveloped jaws (mandibles)used to crush attackers, such as ants.

Nastute soldiers occur in Nasustitermes species and are only rarely found as pests in Victoria. Theyhave a snout from which they eject a sticky solution which irritates and glues attackers.

Phragmotic soldiers have a very large head, which can be wedged in tunnels to block attackers. Thedrywood termites, which use this strategy, are only occasional introductions to Victoria.

WorkersThe workers account for the largest number of termites within the colony, and are thereforeresponsible for the most damage.

They gather food, groom other termites, construct tunnels and repairdamage in addition to tending to the kings, queens and their young.These termites are believed to work 24 hours a day throughout their 4year life span. Worker termites are generally unpigmented. They areblind, wingless and have undeveloped reproductive organs.

Eggs and youngTermites hatch from eggs that have been tended by their nest mates in specially constructed nurseries.



As soon as they are old enough, the young work within thecolony where jobs change with age and maturity.

Colonising flightOnce a single colony becomes sufficiently large it produceswinged reproductives which wait in specially constructedchambers until ready to leave the nest and undertake acolonising flight.

They leave the nest as a swarm under conditions of high humidity, still air, and sometimes low light.Termites are not strong fliers and usually only fly up to 1km, although breezes and updrafts can carrythem a lot further.

Upon landing near a suitable nest site, the female sheds her wings and emits a calling scent. Malesquickly respond.

They dig in and over the next few weeks, mate and take care of their young until enough workersdevelop to take over the care roles.

New colonies are sometimes established via budding. This is believed to occur when the extremities ofthe colony lose contact and become independent.

The primary king and queen are believed to emit hormones, whichsuppress the sexual development of the rest of the colony. However,this control breaks down if the territory is too large or contact withgroups is lost.

Termite life cycle

Termites work together in nests or colonies. They hatch from eggs aslarvae, which are fed by adult termites. They then develop into four forms or ‘castes’ of termite:

Alates – have eyes, wings, darker colouring and are fertile.

Soldiers – have large, dark heads, are blind, wingless, and have undeveloped reproductiveorgans. Soldiers are tougher than other castes and may take longer to control. Some species ofsoldier termites have strong jaws (mandibles) used to crush attackers, such as ants.

Workers – are colourless, blind, wingless and have undeveloped reproductive organs. Workersare the largest caste within a colony and are, therefore, responsible for most damage.

Reproductives – that are darker in colour to other castes, have functional eyes and robust skin.This caste becomes the leaders of future colonies.

The temperature, food quality, and activity of the colony will determine how long it takes for a termite todevelop from egg to adult.



Termite nestsNests and tunnels arekept moist becauseworker termites cannotstand low humidity forlong periods of time. Thetemperature within thenursery of a large nestranges between 10 °Cand 35 °C but rarelyvaries more than onedegree a day. The relativehumidity is approximately100 per cent. Themoisture required tomaintain the temperatureand humidity is obtainedfrom the soil, leakingplumbing or decayingtimber.

Pest termitesIt is important to correctlyidentify the type of pesttermite before beginningtreatment. This will helpyou understand the habitsof the colony, locate thenest and indicate the most appropriate method of control.

Termite species are best identified by their soldier termites, which has the most prominent features.

Coptotermes

These termites are widely distributed throughout Victoria, and are responsible for more than 80 percent of termite damage to buildings.

Coptotermes’ soldiers have brown, saberlike jaws. They measure 3.5–6.5 mm in length. Whendisturbed, these soldiers eject a white, rubbery gluelike substance from their pearshaped heads.

A colony of Coptotermes typically includes half a million termites, but may include up to 1 million.

Coptotermes build nests in trees (preferring eucalypts), stumps, under concrete flooring, in wallcavities or enclosed verandahs.

These termites travel at least 50 metres from the colony via a series of underground tunnels to findfood. Coptotermes acinaciformis send large numbers to new food sources and, therefore, respondstrongly to bait. In contrast, Coptotermes frenchi explore widely for new food sources and feed lightly



at multiple points. They respond less strongly to bait.

Nasutitermes

Nasutitermes are found throughout Australia; however, thespecies are less problematic in Victoria.

Nasutitermes exitiosusis common north of theGreat Dividing Range.They construct dark,thinwalled moundnests between 30 cmand 75 cm aboveground. These mounds are up to 1m in diameter.

Nasutitermes exitiosus soldiers are most commonly found attacking garden timbers.

Porotermes adamsoni

This is Victoria’s largest species of termite, sometimes called dampwood termite. They are usuallyfound nesting in large pieces of timber (particularly older trees) and are most common in wet,mountainous areas. They may, however, also be found in the dry foothills of Melbourne.

Porotermes tend to live in smaller colonies than other species, and do not construct shelter tubes ortravel far underground. They are more easily controlled than other species.

Schedorhinotermes

These termites are found throughout Australia, but only in the north of Victoria.

A mature colony of Schedorhinotermes will have two distinct sizes ofsoldiers, referred to as ‘major’ and ‘minor’ soldiers. Major soldiers growup to 5.6 mm long, while minor soldiers are only 3.6 mm long. Bothtypes of soldier have mandibles.

Schedorhinotermes are destructive and relatively nomadic, rather thanmaintaining a fixed, central nest.

Heterotermes ferox

Heterotermes are widely distributed throughout Australia. However, they are only a major pest speciesin the Northern Territory.

The soldiers of this species are up to 4.75 mm long, with lengthy, dark jaws and parallelsided heads.

Heterotermes live in small colonies that attack fence posts, timber flooring, and paling fences within asmall radius of the nest. They are commonly found because they feed on small timbers on the soil



surface.

Pest termite control – methodsIt is preferable to control colonies before installing physical barriers.

DustsDusts work to control termites because they ingest and distribute the insecticideamong the colony during habitual grooming.

Insect growthregulator dusts (such as Triflumuron) and nonrepellent termiticides are the safestmethods of termite dust control for the human consumer.

Arsenic trioxide dust has been used since the 1930s to control termites, often with the addition of ferricoxide or another colourant. However, arsenic trioxide is a poisonous, highly toxic elemental pesticidethat does not degrade.

BaitBaiting is often the best way to kill an attacking colony when the main nest site cannot be found. Baitstations also allow you to collect samples of termites for species identification.

Bait stations consist of containers of cellulose materials such as timber, paper or cellulose gel whichare either buried in the ground near the building under attack or carefully placed inside near knowndamage.

Bait generally use slowacting, nondetectable toxins so that the nearly whole colony can be poisonedbefore adverse effects appear. Repellent termiticide formulations such as those of pyrethroids are notas colony control agents. Care must be taken not to cross contaminate baits with even tiny residues ofother pesticides.

Baiting does not provide a useful barrier. The baits do not isolate the building as termites are still ableto access the structure. For longterm structural protection, barriers are preferred.

Chemical barriersThis method tries to isolate the termite colony from the building being attacked.

Chemical barriers work by applying an unbroken boundary of pesticide around the exterior of aninfested structure. This creates a zone or band of toxic soil that the termites cannot cross. Creating aneffective chemical barrier may involve trenching around the foundations of the structure, and injectingthe chemical into the soil through holes drilled in concrete foundations.

Termites work through the treated soil unaware that they are picking up a toxic chemical. This greatlyreduces the termite population and may destroy the colony.

Repellent chemicals, such as Bifenthrin, are commonly used as barriers. Nonrepellent termiticides,such as Imidacloprid and Fipronil, may be more resilient where coverage is uncertain (for example,where the chemical is injected through concrete).

Soil may also be treated with a chemical barrier prior to building construction. Bifenthrin is commonlyused for this purpose; Imidacloprid is often used for the exposed perimeter of a new structure.



Physical barriersPhysical barriers are the leasttoxic method of termite control for new buildings.

This method isolates the termite colony from a building by creating a complete barrier around orbeneath a building’s foundations that termites cannot cross.

Physical barriers can be made of a variety of materials, including:

Crushed granite of a particular shape and size. Termites cannot get into a building if graniteparticles are too large and heavy for them to move. Granite aggregate is commonly appliedaround pipes and behind the lower bricks of a building parameter that has a concrete slabfoundation.

Marinegrade stainless steel mesh can be glued to concrete slab foundations, masonry andaround pipes through slabs. Termites cannot enter through the small mesh openings.

Strip shielding, such as metal ant caps on the tops of stumps under suspended timber floors,can also help prevent termite attack. If installed properly, termites have to construct an easilyvisible mud tube over the cap to penetrate the building.

Metal sheeting through brick piers and masonry walls.

Chemically impregnated sheets that have a repellent termiticide in polymer film or geotextilefabric held between two polymer films. The termiticide dosage is determined by the expectedlife of the building. Current examples use either deltamethrin or bifenthrin repellents.

Reducing risk of timber attackRisk of termite attack to timbers may be reduced by controlling moisture, using resistant timbers (seebelow) beneath floor level, avoiding contact between timber and ground or using nontimber elementsin construction (for example, concrete masonry and steel). However, it is notable that research fromthe Australian Commonwealth Scientific and Industrial Research Organisation (CSIRO) has shownthat rates of termite attack are not related to building frame type; steelframed homes are also attackedbecause termites find other food sources inside.

Naturally resistant timberCertain species of timber, such as Red gum and White cypress pine, are naturally resistant to termiteattack. However, all timber cut from a resistant species will not be equally resistant. Accordingly, thesetimbers may be used in ground contact or for subfloor framing, but strip shielding or alike should stillbe used to prevent termites reaching the structure above.

Regrowth timbers of resistant species tend to be less resistant than oldgrowth timbers andplantationgrown timbers.

Chemically treated timberTimber treated with copper, chromium and arsenic (CCA) is listed as a restricted chemical product bythe Australian Pesticide and Veterinary Medicines Authority (APVMA). This restricts the purchase anduse the product, and the areas where it can be used.

Other effective, nonrestricted treatments, especially quaternary ammonium compounds, are graduallyreplacing the arsenic components and have a similar green appearance.

Termite pest control – advice to homeowners



Privacy StatementCopyright NoticeDisclaimer Notice

Page last reviewed: 08 Oct 2015

https://www2.health.vic.gov.au:443/publichealth/environmentalhealth/pesticideuseandpestcontrol/commonpestsinvictoria/termitespestcontrol

https://www2.health.vic.gov.au:443/privacy

https://www2.health.vic.gov.au:443/copyright

https://www2.health.vic.gov.au:443/disclaimer

This web site is managed and authorised by the Department of Health & Human Services, StateGovernment of Victoria, Australia

© Copyright State of Victoria 2015.

Termite pest control – advice to homeownersTermites require food (wood) and water keep the humidity within their nests high, and thus, theircolony alive. Homeowners can help prevent termite attack by removing these needs.

Pest control operators should suggest ways to do this, such as:

ensuring soil is not in contact with susceptible building timbers or impinging upon inspectionzones

ensuring subfloors are well ventilated and remain dry

using only resistant timbers below floor level

avoiding storage of wood directly on soil, under, around or in contact with buildings

improving drainage and fixing leaky plumbing to reduce available soil moisture.

Acknowledgements The department would like to acknowledge the assistance and advice of Don Ewart in the productionof this information.

Contact details

Pest Control Program

Phone hours are: 9 am to 12 pm, Monday to Friday. Direct all other enquiries to the pest controlemail address. Postal address: GPO Box 4541, Melbourne VIC 3001

Telephone: 1300 767 469 | Fax: 1300 881 [email protected]

https://www2.health.vic.gov.au/privacy

https://www2.health.vic.gov.au/copyright

https://www2.health.vic.gov.au/disclaimer

mailto:[email protected]

pest control – termites · termites are often wrongly called ‘white ants’. this term should...

Documents