Wood Borer in the building structure

Wood Borer is a very common invader pest in New Zealand – many pre seventies homes have Borer to some extent in the structure somewhere. Often Borer is found in damper areas where there is some airflow. Damp conditions can make wood more susceptible, however most homes in New Zealand are at the desirable moisture content range to host Borer comfortably. The wood type utilized in the home plays a role in the infestation progress- some timbers are more acceptable to Borer having more available sugars in the wood. Bare wood and sawed  timber allow easier penetration and will often be attacked initially over harder wood with a smooth surface as will Timber with higher moisture content.

Wood borer

There are several known Borer types in New Zealand with only three generally found in structures. The Two toothed long horn is the most infamous- it is a close relative to the Huhu grub, it is large in size and will seriously damage a site structure in one life cycle- their presence is obvious and infected wood should be cut out and burned- the surrounding unaffected timber should be professionally preserved. This species is relatively rare inside the home but the Common house Borer is not. Much smaller in size their damage is less aggressive but their life cycle is much shorter and they multiply faster- damage is often more intrusive than observed.

Modern day timber treatment effectively prevent infestation, however this was not always the case, in the fifties it was becoming common the heat treat timber at the mill. This is said to be effective at killing Borer, however this does not protect even marginally against post milling introduction. This is where most Borer’ is suspected to originate in the home.

Post milling treatment- many homes in New Zealand need to be treated at some stage for Borer infestation, in order to preserve structure strength and mitigate further damage. There are four common treatment methods utilized for structural Borer.

Boron treatment

This is a method often referred to as wood preserver. This treatment usually in dry powder form and mixed as a suspended solution with water and is either sprayed or painted on wood – The ingredient is usually Boric acid with the addition of Boron- it is considered safe for humans and can be purchased without a license. This is a common do it yourself method and commercial pest controllers offer this method for general borer control in both ceiling cavities and subfloors with Borer activity. Effectively this is a suspension treatment which remains fixed to the outside surface of the treated timber.

Boric acid will only control Borer when the wood treated is ingested. Borer spend much of its time inside timber chewing around for years without feeding on the timber, rather making more space to be occupied by offspring. Boric acid will kill the Borer when it finally exits your home, it may prevent further eggs being laid as a result. This treatment is less suitable where there is water run off of high levels of moisture retention as it may be removed by contact with the water. In dry conditions it does not degrade quickly and can remain an active control for ten to fifteen years.

Water applied insecticide

This is by far the most common method employed by Pest control companies in New Zealand. It is the most practical to apply and a cost effective method. The insecticide should be applied only by a professional. EcoSan Solutions will utilize a selection of an Organic Pyrethroid. This synthetic Pyrethroid is considered a safe solution for long term control in the family residence. It is fortified to resist breakdown from moisture and sunlight. Unlike Boric acid these treatments will kill Borer on contact, there is no need for Borer to ingest the product. This results in a faster and more reliable control.
Water applied insecticide will penetrate 5mm into the timber in most Borer infected wood, this increases the chance of Borer making contact with the treatment earlier. The deeper the penetration of the product, the faster and more reliable the control will be.

This treatment is similar to Boric acid but has an advantage-of killing without the target ingesting the ingredients. It may control the borer before it exits the timber decreasing the Borers opportunity to lay eggs before it is killed. When professionally applied it is very feasible control will be gained over time- however it may not prevent Borer from further damage before the target makes an exit.

  • Insecticide is oil borne and even in water will penetrate slightly deeper than Boron by comparison

  • It kills on contact and does not require ingestion to control the target

  • May control Borer inside the timber more quickly than Boron.

Re treatment of the timber is recommended every five years with this method.

Solvent suspended insecticide

This method is hands down the best control available and is superlative to other options. Solvent suspension is the only method which can guarantee a complete control to timbers treated- insecticides utilized for Borer control actually have a considerably longer life when mixed with solvents as opposed to water- hydrolysis will induce early inefficacy in both organic and synthetic insecticides this is not an issue with solvents. Testing has confirmed where solvents are utilized in timber control- within seven hours the majority of the timber is saturated with the product- in other words, the control treatment absorbs into the wood almost all the way! A twenty four hour period and the timber is over 90% completely saturated. The downside of this treatment is the cost of the materials and ingredients are higher and specialized equipment is required with the application.

The upside of this treatment method is the control is complete – in many cases it will kill the adult Borer and it’s full life-cycle 24 hours post treatment, period. The residual qualities of this treatment will remain for several years.

Ethylene suspended Alkali salts

Ethylene suspended Alkali salts is a highly effective method for Timber pest such as Borer, Termites, Fungus, Mould and Dry rot. These treatments are most suitable for applications during home and building renovations where original untreated timbers are preserved or where treated timber may require maintenance prevention against Timber Pests and Rot.

These treatments are often used to satisfy council sign off conditions. In these cases they are applied using a dye marker to indicate the timber has been treated sufficiently.

These treatments can be painted on for smaller areas or for spot treatment or sprayed on to timber for larger or difficult to access areas.

  • Ethylene is highly hygroscopic. Even in wet wood in will penetrate through water, absorbing deeply

  • Acts as a penetration agent, binding to insecticide and carrying it into the timber

  • A very strong Fungicidal agent. It kills and give years of protection against all types of timber Rot

  • An excellent option for treating under the house where dry rot is an issue

  • Higher tolerance to extreme temperature so remains stable in any environment

  • Adds anti Fungal and anti rot qualities to Boron and insecticide treatments

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