These microorganisms include surface moulds, blue stain fungi, fungi causing wet and dry rot and bacteria. Some (e.g. blue stain) mar the appearance but not the strength, whereas the fungal rots can completely destroy affected timbers, reducing them to soft, spongy material with no strength.
Often misnamed 'white ants', termites prefer moist, dark conditions and are extremely destructive to timber. They eat out the inside of wood, along the grain, leaving only a thin shell of wood.
This destruction can be avoided by using termite-resistant timbers, and by isolating timber from the ground, through which termites travel. Subterranean termites travel inside tunnels, as they avoid light and preferred darkness.
Air gaps have been proven to be an effective way to deter termites, which must as a result build mud tunnels to avoid desiccation wherever they travel through air gaps.
Metal ant caps on top of walls do not prevent termite infestation but they do deter attack and they can make it obvious as the termites must build over the projecting metal angle.
Powder post beetle (Lyctus)
This wood-boring beetle infests cut timber. It lives off the starch in the sapwood of pored (hardwood) timbers and, although confined to sapwood, can cause considerable damage. In NSW, before being marketed, most susceptible timbers are required to be treated with a preservative that is toxic to this beetle.
Furniture beetle (Anobium)
This borer, which also lives off starches in the wood, chiefly infests the sapwood of seasoned softwoods and can cause extensive damage in untreated wood. The tunnels that are bored out form a honeycomb appearance in the timber, leaving a deposit of fine gritty dust. Affected timber should be treated or removed and destroyed, to prevent spread.
Pinhole beetle (Ambrosia)
These beetles attack almost any tree species but only the green timber. The beetle is killed off as the timber dries out with seasoning. Various chemicals are used to prevent or destroy infestation.