Masa’s expertise in termite treatment is unrivalled
Pretreating wood prevents losses
Dr Natalio A Mercado, company entomologist at Masa’s research and development department describes in detail the pests that attack wood and effective methods for their control and elimination.
01 May 2012
WOOD can be treated for termites and other wood-destroying organisms either as a preventive measure or to eliminate existing above-ground infestations, with the opportune time being prior to construction in the form of preservative-treated lumber and plywood.
Most lumber in Saudi Arabia and other part of the world is not pre-treated, making it vulnerable to termite attack and causing damage valued at millions of dollars each year. Hence, treatment of structural wood already in place is often necessary.
Most termiticides used for soil treatment can also be applied to wood. In addition, a number of general pest control insecticides are also labelled for this purpose. Typically, the formulations are sprayed or injected under low pressure into the galleries of termite-infested wood through small holes drilled in the wood. Pressurised aerosol systems have been used in the past to aid dispersion throughout the gallery system.
None of the above applications is intended to be a substitute for soil treatment or necessary mechanical alterations as their primary purpose is only to provide supplemental control of above-ground areas of termite activity. If the wood is sufficiently moist, these termites could survive several months or perhaps indefinitely if moisture is present due to a leak or condensation. Treating infested wood in conjunction with the soil can also lessen the risk of post-treatment swarms and their associated callbacks. Another opportunity for wood treatment is around wells, cisterns, or sensitive locations where conventional soil application is inadvisable.
While wood treatment alone may not solve the problem, it can fit nicely with other approaches, including the use of baits.
Soil treatment is the principal method used in control for widely varying types of construction and even within small regional areas, making it necessary for the termite control specialist to think in terms of the principles of control involved in each situation and to adapt control methods to fit the situation.
The major objective of the specialist in soil treatment for subterranean termite control is to establish a chemical barrier between the termite nest – usually in the ground – and the wood in a structure. In buildings under construction, this is accomplished by keeping wood out of contact with the ground and by penetrating the soil below the foundation with insecticide to establish a chemical barrier.
In completed buildings, the barrier is made either with termiticides or by modifying the existing structure to create a mechanical barrier. Nonetheless, the goal should be a thorough application, because gaps of untreated soil are generally associated with treatment failures. It is particularly important to place the liquid termiticide in a way so as to deny termite access to entry points and that termites attempting to penetrate through the treated soil are either killed or repelled.
A crucial factor that determines the performance of all products is the thoroughness of treatment. Regardless of which termiticide is used, the most common reason for re-treatment especially within the first year of application is because of a failure to deliver the chemical to the termites or termite entry points. This should come as no surprise, considering that termites are able to enter buildings through cracks and holes no bigger than pinheads or more precisely, about the width of a termite head capsule, which for most species is less than 2 mm.
Control methods
A complete termite control treatment may involve any of the following basic steps: mechanical alteration, soil treatment, foundation treatment, and wood treatment.
• Mechanical alteration involves modifying the structure so as to provide a barrier that cannot be penetrated by termites, or to eliminate conditions that are conducive to termite invasion.
• Soil treatment consists of the application of termiticides to the soil under and adjacent to a building to create an impervious chemical barrier. A continuous barrier should be established along the inside and outside of the foundation, under slabs, and around utility entrances.
• Foundation treatment is the application of termiticide to a foundation to make it impervious to termites. The objective is to place termiticide in all cracks at the footing as well through cracks in the foundation wall that may lead to the ground outside. Treating the inside of hollow concrete block walls is another example of foundation treating.
• Wood treating is the application of insecticide directly to wood to eliminate existing termite infestation or to make the wood impervious or resistant to termites.
As a general rule, the first three methods are used in termite control practice, with wood treating being a pretreatment or supplemental measure. Pressure-treated wood is frequently used in the construction of buildings and provides effective termite control if it is used for all wooden construction or, at least, to the ceiling level of the first floor.
Spraying insecticides on wood already in place provides only surface protection and doesn’t penetrate to the centre of the wood, where it is most needed. In badly damaged wood, insecticides can be injected into the cavities made by termites. This will provide better control than will a brush or spray application.
Alteration of environmental conditions might one day be the only procedure necessary to eliminate some infestations of wood-boring insects. As wood-boring insects in buildings cannot proliferate in wood that is dry, the use of vapor barriers, ventilation, and central heat to keep wood dry, would render other control measures unnecessary. However, as this is not a rapid means of control, it probably would not completely replace others.
Regardless of the method used, it is wise to recommend that every effort be made to reduce the moisture content of the wood to be protected to below 20 per cent. Moisture meters can be used to determine moisture content of wood, walls, and other materials suspected of harbouring termites.
Where economical and practical, infested wood should be removed and replaced and any adjacent wood must be carefully inspected to ensure that it is free from wood-boring pests.
Electric current and heat treatment have uses in some wood-boring pest infestations. However, every situation should be evaluated before making a decision on the treatment method(s).
In chemical treatment, there are certain similarities in measures recommended for the control of wood-boring pest, but in many instances specialised techniques are required. In addition to determining the type of wood being attacked, each problem must be analysed in light of the severity of infestation, possibility of re-infestation, the area of the structure being attacked, the speed of control needed, and the property owner’s budget.
Residual insecticides approved for use against wood-boring insects are effective when applied properly. In the past, it was thought that oil formulations result in better control than water-based emulsions because of the greater penetration into wood, but this is not the case. Furthermore, oil solutions are a possible fire hazard, are more expensive, cause discomfort to the applicator, and endanger plants near the treatment area.
To obtain the best results, the pest management professional must combine knowledge of the wood-boring pests with knowledge of insecticides. Another problem is ensuring that the insecticide reaches the insects concealed and well shielded in their burrows. Although materials with a long residual life would kill wood-boring insects shortly after they emerge, it is preferable to kill them in their tunnels so they don’t mar the surface of the wood with holes when they emerge.
Fumigants are most effective in penetrating tunnels. However, the danger in handling these materials and the fact that they have no effective residual life limits their desirability.
Periodic inspections are needed to determine the condition of wood and the presence of any pests. It is necessary to visually examine all exposed surfaces of painted and unpainted wood and to probe them for evidence of internal hollow damage, which is the only way to make a positive identification of the attacking pests and avoid unnecessary treatments. Since termites and beetles cause damage very rapidly, any delay in treatment is risky. The inspection will also help reveal whether the infestation is still active through finding fresh frass of newly sawed wood, or live larvae and adults in the wood.
Decay of wood in buildings is a problem in moist, humid parts of Saudi Arabia. The moisture promotes the growth of fungi that cause rot and hence when wood is used in the construction of a building, it should be well seasoned, to ensure it does not contain enough natural moisture to support these fungi. As wood in unventilated crawl spaces under houses is prone to be damp, pest controllers can address this situation by providing proper drainage and ventilation, installing a vapour barrier, and treating the wood.
The pest control management programme by Saudi-based Masa Establishment for Pest Extermination, Maintenance and Contracting, adopts only the most effective and proven techniques and practices in pest control as well as standard operating and quality procedures incorporated in the company’s policy guidelines that are designed to meet customers’ requirements and satisfaction.
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