Consuming Interest
Worm the Wood
By LESLIE ADRIAN
IT may be an ill draught that blows down your neck as you sit by the fire, but at the same time it will be discomforting to ,iwrulius lacrynjans, our old ( I ) enemy dry rot, who hesitates to settle and reproduce himself in well-ventilated houses. Ap- parently it is the sounder construction of modern houses that makes them liable to attack by the dry-rot fungus, which flourishes in conditions that keep the moisture content of woodwork above 20 per cent. The winter is a time of apparent inactivity on the part of the so-called woodworms, better known as the death-watch beetle and the furniture beetle, although the dry- rot and other fungi continue to flourish, but the summer's outbreak of tiny holes in furniture and beams which are infested ('flight holes') is the culmination of a long period (anything up to thirty-three months) of tunnelling and eating by the larvae of the beetle. In the summer the beetles emerge and fly freely, the females alighting on other timbers near by and laying up to fifty eggs at a time; but the winter is the time to launch a counter-attack.
The life-cycle of the death-watch beetle starts when the eggs are laid invisibly in tiny flaws in the timber surface. Four to five weeks later the grubs, the woodworms in fact, begin to bore their way into the wood, eating as they go. For nearly three years they tunnel happily about, finally arriving just under the surface again to enter their Pupal stage, after which the baby beetle bites its way out, leaving the characteristic hole. The furni- ture beetle's life-cycle is similar, and the effective counter-attack is very much the same.
If ,help is needed in identifying a particular pest or fungal infection, the Timber Development Association (21 College Hill, EC4), an independent organisation, will give free diagnosis and advice on treatment to anyone who sends (in an air-tight tin, box) small samples of the affected. wood. Treatment of the affected woodwork can be a tedious task, and if the job seems impossibly large the Woodworm and Dry Rot Centre (23 Bedford Square, London, WCI) will offer effective advice, on the spot if necessary. 'The advice is free for isolated areas of infection, but a charge of. £5 5s. is made for a complete survey of a house, its furniture and outhouses. They also have branch advice centres in Birmingham, Bristol, Leeds, Manchester, Glasgow and Belfast. The centre, which houses a hair-raising exhibition, open to the public, of the ravages caused by dry rot and the wood-boring beetles, is maintained by Rentokil Ltd., whose timber fluids will be recommended for the disinfestation. A furniture preservation service will be available at the centre from next week.
. Wood preservation and protection is a highly technical matter, and it is virtually impossible for a layman to tell if an outbreak, whether of 'worm' or dry rot, is really small, and not a visible sign of a larger, invisible attack. Conversely, the layman may alarm himself unnecessarily by mistaking wet rot for dry rot, or the sight of the relatively harm- less pinhole beetle may give rise to groundless fears of infestation by his more destructive cousin. But where there has been an attack of either dry rot or worm, penetration into the wood is essential to wipe out the eggs as well as the insects, and where possible the insecticide should be-injected into the flight holes. With furniture, inside surfaces should be treated as well as outside ones, and insecticidal wood dyes and polishes can be used to protect the vulnerable surfaces. Where floor- boards show signs of attack one or two should be prised up so that the joists can be seen. The death- watch beetle will frequently infest timber which has been previously softened for him by fungal infections, particularly dry rot. The dry-rot fungus enters the surface of the wood when it is still lying in the forest, and like many germs in our bodies, it only becomes active in 'ideal' surround- ings. It is unlikely to flourish in well-ventilated, dry conditions, but the fungus, and therefore the beetle, are most common where wooden beams are embedded in masonry or brickwork. .
Dry rot inhabits cellars and basements and hollow floors especially, which is the reason why a well-built house should have ventilators and air- bricks at strategic points, as well as damp courses (which are kept free of obstructions), to keep the moisture content of the wood as low as possible. One of the remarkable things about dry rot is the distance which may be covered by the mycelia, a network of fine white threads, like roots, thrown out by the fungus as it seeks Cellulose upon which to feed. A polished surface or a layer of paint may conceal the fungus at work. Points to look for : fine cracking and a buckling of the surface, the cobweb-like mycelia, traces of the red-brown spore dust, wood so softened that it is easily pene- trated by a penknife and a characteristic musty smell. Signs similar to these (although there is no unpleasant smell) are shown by wet rot, also a fungal infection of timber, but much less serious in its consequences.
Treatment for dry rot has to be drastic. Wood- work showing obvious signs of fungus must be cut out and burned. (Unfortunately it is not illegal for such wood to be chopped up and sold as kind- ling, bringing dry rot into the home of the luck- less purchaser.) The cutting should extend to a radius of three feet around the affected place and two applications of dry-rot fluid applied to the entire area, including the new timber put in to re- place the affected wood. Faulty ventilation should be corrected and all surrounding surfaces scrubbed (brick and metal as well) with a wire brush. Brickwork is best treated with a blowlamp to burn off the mycelia.
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