Gulf Construction Online - Masa tackles pests that destroy wood

Timber

A Masa operator treating termite infestation.

Masa tackles pests that destroy wood

01 May 2016

MOHAMMAD ARIF HUSSAIN, entomologist at Masa, warns that termites could do extensive damage to buildings and their contents and the best time to tackle the problem is pre-construction.

From the earliest times, timber has been used as a component of traditional buildings – for floors, walls, windows, doors and roofs.

A variety of factors can lead to its breakdown and decay, including attack by insect pests – the most damaging of which are termites, followed by beetles.

On the basis of distinctive habits and problem-solving challenges, beetles rank near the top. These are of two kinds: those that will reinfest the wood they have emerged from until the wood can no longer be used and must be replaced; and those that emerge from wood after it has been milled (and installed for whatever use it was intended).

Third in importance, depending upon geographical location, are bees, wasps, and ants. Fungi are also an important source of damage to wooden structures in areas where the climate is warm and humid.

All pests of timber have one thing in common: they attack wood and cause damage worth millions of dollars each year.

Termite behaviour

Focusing on the most damaging of these pests, termites hate light and heat, preferring dark moist environments because their bodies are very prone to desiccation (drying out). They will never be found in the open and their activity is always well inside the timber they are feeding on. In severe infestations, they may eat most of the available timber, leaving only a very thin veneer on the surface. Commonly, they will completely gut a piece of wood leaving no evidence on the outside.

They dig underground galleries in their quest for wood. These galleries preserve the moist atmosphere of the nest, shield the termites from light and protect them from predators (largely ants). Their network of galleries can stretch up to a hundred metres from the nest in search of food.

Termite prevention

If there are termite problems in the neighbourhood or the area is termite prone, it may be wise to obtain a pest inspection. The cost of such an inspection compares favourably with the cost of eradication and replacement of affected timbers. Saudi-based Masa offers a free-of-cost inspection of the area under termite infestation.

To safeguard against termite attack, several precautions should be taken:

• Remove all timber debris from under the house, since its presence encourages foraging termites. Move piles of timber or firewood (potential food source for a new colony) away from the house, and store the timber in a dry, well-ventilated location. Old decayed tree stumps should be removed to below ground level. If termite activity is suspected, arrange an inspection by an expert.

• Never disturb an area suspected of termite activity. This prompts the termites to move elsewhere which makes future detection and eradication more difficult. It may also result in the damage being increased elsewhere.

• Provide good ventilation under all suspended floors. The reduced humidity and moisture makes the subfloor area vastly less attractive to termites. Leaking water pipes or bad drainage encourages termite presence so these faults should be remedied.

• Examine new constructions. For example, verandahs and timber decking, if built on stumps, may not have ant caps. These constructions, and concrete additions to the house, may also bridge previously laid chemical treatments, permitting unobserved termite entry. The underside of a concrete slab is a popular place for termite nests. If concrete is laid next to the timber frame of a house, damp conditions may be promoted and termite entry would be extremely difficult to detect.

Termite control

For many infestations, insecticide treatments are needed to control established termite colonies. However, most subterranean termite control is done by applying either termiticides to the soil or termite monitoring/bait stations in or around the structure. Liquid termiticide treatment involves applying termiticide to the soil beneath and adjacent to a building to create a barrier. These barriers are not applied to eliminate the termites nesting in the ground, but rather to kill any termites that would tunnel up to it, thereby protecting the structure. For optimum protection, a complete barrier should be established around and under the structure.

Trenching around the structure and drilling into the slab must be done to establish a continuous barrier. The actual length of time a termiticide treatment remains effective around a structure depends on the thoroughness of the application, termite foraging intensity, conducive conditions and environmental conditions. The effectiveness of liquid termiticides varies due to soil and climatic differences.

Control measures against termites that can guarantee results is the development of chemical barrier around and below the building. This can be accomplished by several ways, including rodding, trenching, spraying, drilling, injecting, plug-in, and patching. Soil treatment against termite infestation can be done in two stages:

• Pre-construction: This refers to the application of termiticide emulsion during the construction stages of a building, starting from the foundation footing and the outside perimeter. This treatment depends on the manner a structure is going to be built as well as the structural composition of the building. Also termed as termite-proofing, this method guarantees a complete chemical barrier.

• Post-construction: This treatment is done in existing buildings, mainly by drilling, injection and patching. Sometimes trenching and rodding is also done, with the focus being on having a continuous chemical barrier that will block termite entry. The main entry points for termites are foundations, expansion joints, the outside perimeter wall, and cracks in flooring/foundation walls and footings.

The pre-construction treatment is more effective in controlling the termites than the post-construction treatment. Chemical barriers remain the standard method of controlling termites. There is no single technique among the newly-developed ones that can claim to be a standalone method of termite control – and all these new methods provide extra tools for integrated pest management (IPM).

Masa, which has a selection of termiticides, recently registered a new termiticide of the Neonicotinoid family, Raslan Plus, with the Saudi pesticide regulatory authority SFDA (Saudi Food and Drug Authority). Raslan Plus has the active ingredient, Imidacloprid 30 per cent SC, which is a systematic and contact insecticide that is ecofriendly and has low toxicity towards people and animals. It is odourless and creates a non-detectable treated zone that functions not as a repellent zone/barrier, but as a “killing field” whose effects may be transmissible to other termites and leads to contamination of the colony.

Dampwood termites

These termites are not considered to have significant economic impact on timber in service. These generally tend to feed only on damp or rotting timber. Dampwood termites are rarely found in dry timbers in buildings and do not attack buildings unless there is timber-soil contact that allows access to other timbers. They pose little hazard once the wood is isolated from the ground and conditions become dry. The risk of infestation is reduced significantly by isolating wood from the ground and preventing dampness. Affected timbers should be replaced.

Timber borers

There are several types of timber borers, some serious and some not, so it is important to identify them. Borers are actually the larval form of different families of beetles – generally powderpost, deathwatch, and false powderpost, and invade and damage wood furniture as well as structural and decorative wood inside buildings. The beetle larvae feed in and do most of the damage to wood, and when they reach the adult stage, they emerge through round exit holes, which they create by chewing through the wood surface.

Fungal decay

Timber may also be affected by fungal decay. Timber-affecting fungi reproduce via the release of microscopic spores, which can be carried long distances by wind, air currents, water or even on animals. Spores will germinate on damp wood – with a moisture content of 30 per cent – using the timber cellulose as a food source.

Fungal activity will be determined by the type and durability of the timber, its level of protection – for example, paint or finish, and environmental conditions, although activity may continue within the already decaying timber even with reducing moisture levels. Environmental conditions conducive to fungal attack are similar to those conducive to timber pest infestation. Rectification of these conditions may prevent local, as well as invasive, attack by both types of timber pests.

Masa Establishment for Pest Extermination, Maintenance and Contracting, a pioneer in pest control management in Saudi Arabia, has a comprehensive knowledge of the way insects live as well as safety measures to control the insect pests.