What Timber Pests does PestWISE cover?
Termites
General Description of Attack
Timber hollowed beneath; some cracking at the surface of timber; earthen channels present; or pale faecal spots present.
IMPORTANT NOTE. As a delay may exist between the time of an attack and the appearance of telltale signs associated with the attack, it is possible that termite activity and damage exists though not discernible at the time of inspection.
Treatment
After discovery of an active infestation, it is imperative that the species of termite is accurately identified before costly (and sometimes unnecessary or inappropriate) methods of treatment are initiated. Only economically important species which are known to attack timber structures should be treated.
In the case of economically important species, it is important that the termite workings are not further disturbed until the proposed method of control has been determined by a licensed pest control operator. Premature attempts to repair or replace infested timber may cause the termites to withdraw from the area temporarily, thereby hindering effective treatment. Any repair or replacement of infested timber should be carried out after the appropriate treatment has been completed.
Where evidence of active termites is detected within a building or within 50 metres of any building, it must always be assumed that the termites may also be active in areas of the property not inspected. Accordingly, where the termites are known to be of economic significance, a further (more invasive) inspection is strongly recommended of areas which were inaccessible, not readily accessible or obstructed at the time of inspection.
Termite Workings and Damage
Where evidence of damage to building timbers exists, competent advice (e.g. from a licensed or registered building contractor) should be obtained to determine the extent of any structural damage and as to the need or otherwise for rectification or repair work.
Where evidence of inactive termites is located within the building, it is possible that termites are still active in areas of the property not inspected and they may continue to cause damage. A further more invasive inspection is strongly recommended of areas which were inaccessible, not readily accessible or obstructed at the time of inspection.
Where evidence of an inactive termite infestation exists, it is not possible, without benefit of further investigation and inspections over a period of time, to ascertain whether any infestation is active or inactive. Continued, regular, inspections are essential.
Where evidence of termite attack exists to any trees or tree stumps a more conclusive search should be undertaken. This may require the tree or stump to be drilled to determine the existence of a termite nest. In addition, the soundness and stability of any standing trees identified as being affected by termite attack should be confirmed. Always seek further advice from the Consultant.
Previous Treatments
Where evidence of a possible termite treatment was located, the Client should obtain and keep on file all relevant documents pertaining to the extent of the treatment, any service warranties and advice in regard to the building owners obligation to maintain the treatment and/or barrier. If evidence of a previous treatment of termite infestation is noted, and appropriate documentation is not available, the Client must assume that the termite infestation may still be active in areas of the property not inspected. Accordingly, a re-treatment may be required. Always seek further advice from the Consultant.
Frequency of Future Inspections
Australian Standard AS 3660 recognises that regular inspections will not prevent termite attack, but may help in the detection of termite activity. Early detection will allow remedial treatment to be commenced sooner and damage to be minimised.
Inspections at intervals not exceeding twelve (12) months are recommended. Where the termite risk is high or the building type susceptible to termite attack, more frequent inspections (3-6 months) should be undertaken.
Wood Borers
General Description of Attack
As the attack proceeds, borer larvae eat through the wood leaving a dust called "frass". Ejection of the frass occurs through the adult beetles flight (exit) holes, and it is usually present beneath any timber that has been attacked. The presence of frass however, does not indicate whether the attack is active or not. Borer larvae cannot be sighted unless the susceptible timber is broken open.
IMPORTANT NOTE: As a delay may exist between the time of an attack and the appearance of telltale signs associated with the attack, it is possible that borer activity and damage exists though not discernible at the time of inspection.
Economic Significance
With the exception of the European House Borer (Hylotrupes bajulus) evidence of borer activity is rarely cause for alarm, but rather for careful consideration of three main points, namely the identification of the particular borer responsible, whether the infestation is still active, and the extent of the damage. Full consideration should be given to each of these items before any action is taken.
- European House Borer
- This borer was discovered in January 2004 in Western Australia and most likely entered from overseas in imports of seasoned timber or timber articles such as furniture. It is considered one of the world's most destructive pests of seasoned softwood timber including untreated pine, fir and spruce. Roof timbers are most often infested.
The following wood borers cause damage most frequently encountered by building owners across Australia.
- The Lyctid Borer
- The most common lyctid borer in Australia is Lyctus brunneus (powder post beetle). Attack usually takes place during the first six to twelve months of the service life of timber. However, the powder post beetle is not considered a significant pest of timber and treatment of infestation is not usually required. As only the sapwood of certain hardwoods is destroyed, larger-dimensional timbers (such as rafters, bearers and joists) in a building are seldom weakened significantly to cause collapse. In small-dimensional timbers (such as tiling and ceiling battens) the sapwood may be extensive, and its destruction may cause collapse. This may require the support or replacement of the affected battens. Competent advice (e.g. from a licenses or registered building contractor) should be sought to determine the extent of any structural damage, and as to the need or otherwise for rectification or repair work.
- The Anobiid Borer
There are many different species of Anobiid borer, the most frequently encountered being Anobium punctatum (furniture beetle) and Calymmaderus incisus (Queensland pine beetle). Attack mainly occurs to softwoods especially pine timbers such as floorboards that have been in service for at least ten years. Should any structural timbers be attacked by Anobiid borers it is often difficult to determine what extent the borer damage has weakened such timbers and replacement is often the only way of ensuring safety from collapse.
In the case of Anobiid borers, once an attack is initiated it is unlikely to cease or die out of its own accord without some sort of eradication treatment. Therefore, unless proof of treatment is provided, evidence of an attack must always be considered active. Although a chemical treatment is an option, replacement of infested timbers with non-susceptible, or treated timber, is the most effective method of treatment. Before any option is considered, competent advice (e.g. from a licensed building contractor) should be sought to determine the extent of any structural damage, and as to the need or otherwise for rectification or repair work.
- Other Borers
- A further (more invasive) investigation is strongly recommended to determine whether infestation is still active and to positively identify the borer species responsible for the attack. Always seek further advice from the Consultant.
Management Program
Wherever practical, remove any conditions conducive to attack (e.g. Anobium borer thrive in badly ventilated subfloor areas). Regular inspections are recommended at intervals not exceeding 12 months. However, in the case of the European House Borer, susceptible building timber in a known geographical area of infestation in Western Australia should be inspected (preferably between April and July) after emergence/flight season to help monitor susceptible timbers. Always seek further advice from the Consultant.
Fungal Decay
General Description of Attack
Decaying wood contains sufficient moisture to retain its original shape and may have sufficient strength to withstand normal loads. In contrast decayed wood is reduced both in moisture content and size as indicated by cracking either along or across the grain or fibres coming apart in a stringy manner. Decayed wood will have undergone considerable strength reduction.
Economic Significance
Fungal decay can cause at one extreme, structural failure of the affected timber, and at the other purely superficial surface damage. The most critical determination is that of which timber is affected and decaying, because decay will most likely spread (unless sources of moisture are quickly removed). Affected and decayed timber may warrant timber replacement, but the rot should not spread unless a new moisture source becomes available in that area.
Where evidence of decayed timber exists, competent advice (e.g. from a licensed or registered building contractor) should be sought to determine the extent of any structural damage, and as to the need or otherwise for rectification or repair work. It is important to correct any condition conducive to attack prior to replacing decayed wood.
Where evidence of decaying timber exists, competent advice (e.g. from a licensed or registered building contractor) should be sought to remove the condition(s) conducive to attack, and to determine the extent of any structural damage, and as to the need or otherwise for rectification or repair work.
Where the full extent of damage or the overall condition of the timber is undetermined a further inspection is strongly recommended by a competent person (e.g. from a licensed or registered building contractor). This may require monitoring of the timber over a period of time and include the assessment of conditions conducive to attack in different weather conditions (e.g. to determine the adequacy of existing drainage).
Management Program
Remove any conditions conducive to attack (e.g. lack of ventilation or the presence of excessive moisture). Regular inspections are recommended at intervals not exceeding 12 months. Always seek further advice from the Consultant.
Chemical Delignification
General Description of Attack
Surface of timber appears very hairy; and wood and "hairs" separate.
Economic Significance
Chemical Delignification of wood in service is only rarely encountered and then only in certain areas. Small dimensional timber members such as roof tiling battens may collapse when the wood becomes defribrated. However, in large dimensional timber members such as rafters, bearers and joists, delignification takes many years to affect the strength of timber to the point of collapse.
Where evidence of Chemical Delignification exists, competent advice (e.g. from a licensed or registered building contractor) should be sought to determine the extent of any structural damage, and as to the need or otherwise for rectification or repair work.