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Old 12th Aug 2014, 9:12 am   #21
David G4EBT
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Default Re: Another woodworm question!

Quote:
Originally Posted by Audio1950 View Post
This illustrates exactly what I have been thinking - just because there are flight holes, indicating that one or more generations have departed, surely that doesn't mean there are no more still happily chomping away inside?
Don't wish to sound contrary or argumentative, but it's highly unlikely that any would remain in residence when you consider the life cycle - they will have been laid as eggs at the same time, several years ago, will mature into beetles at about the same time, and when one generation has matured, you can be assured that there will be nothing left inside that a beetle would consider a suitable place to lay her eggs. (If you ever see a piece of timber split lengthways that's had woodworm in it, you'll see that it's dry as dust with hardly any cellular structure left). To apply woodworm treatment and to have beetles emerge would mean you've caught them just at the instant they've matured from the larval stage and are about to leave, sometime between April and July. But yes, such a coincidence is possible. If perchance there are any larvae still present, and if the treatment did kill them, we might get a slight frisson of satisfaction at gaining revenge on a few hapless larvae, but all too late - the damage has already been done.

The wood-worming beetles lifecycle, (the most common of the four wood-worming beetles in the UK being the furniture beetle), is as follows:

The pregnant female starts the lifecycle by laying her eggs directly into the timber through cracks, crevices and holes. (To protect the eggs they arent left on the surface of the timber). The female beetle lives for only 10 - 14 days - her male counterpart - whose only role in life is to mate with as many females as possible, doesnt even eat - it lives for only 3 -4 days, so the beetles themselves cause little or no direct damage to timber its their offspring that are the culprits, when the eggs become larvae.

After a few weeks the eggs hatch downwards into the timber and produce larvae - that's the 'worm' stage of the lifecycle. The larval phase continues for anything from 2 to 5 years as they munch their way up and down inside the timber, but this goes on undetected as they dont emerge, having no reason to. Its during this long unseen phase of their lives that the structural damage is done, which is of course far more serious in load bearing structural timbers such as roof and floor beams, than in radio cabinets. (The fine wood dust that they produce when they emerge is known as frass).

Towards the end of the woodworm beetle lifecycle, the larvae pupate from the larval stage into adult beetles. The adult beetle then eats its way through the surface of timber producing the round exit holes that we see as evidence of the infestation that has taken place unseen over many years. Once the beetles emerge from the timber, in their brief life of just a few days, they meet, mate, lay their eggs inside the nearest piece of suitable wood, (ie, previously un-infested and with a high moisture content), to continue the life cycle. Then they die - not much of a life if you think about it!

When a radio set has been infested, the radio would have been in a very different environment from that when it is our possession - a damp garden shed, cellar or whatever. If by some slim chance any of us have a woodie radio which still has live larvae in it, close to becoming beetles, and if the beetles do emerge, assuming that we live in a heated and ventilated house, the beetles won't find anything to detain them - they've got just a few days to find a suitable environment in which to perpetuate their species. (Like an old woodie radio in a damp garden shed which hasn't previously been infested. (Or even the shed itself!).

I'm not holding myself out to be an expert - this info is based on knowledge I've gained over the sixty years that I've had an interest in woodie radios, many of which I have to admit, through ignorance, I've doused in all sorts of chemicals and preparations, not appreciating the futility of what I was doing - trying, but failing, to put paid to a non-existent foe! I was given the first such set in the early 1960s by a neighbour. (I still have it - a small Defiant). I've found it difficult to disguise woodworm exit holes and make a cabinet look respecatable and in several cases with simply boxy cabinets, if I've like the set I've either re-veneered it, or discarded the cabinet and made a new plywood cabinet which I've then veneered.

Interesting and relevant topic, that tends to generate more heat than light.
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Old 12th Aug 2014, 8:55 pm   #22
whyperion
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Default Re: Another woodworm question!

April to June - how they know that date or how close they are to the surface is beyond me. I think it relates to age compared to when they hatched, general warming and longer light hours.

Been clearing the in-laws which had an escape of water/damp storage, the wood-boring beetles had liked the damp wood, but more more so the ?cellulose? glues of the plywood furnishings, it seems they find the glues more easy to consume as food source than the wood.
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Old 13th Aug 2014, 10:40 am   #23
brenellic2000
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Default Re: Another woodworm question!

"Longer light hours!" - ah, yes, clocks go forward an hour!! Just kidding. But buried deep in the wood, light can't penetrate and as wood is an ideal insulator, they would't know its getting warmer. It is real mystery... where's Columbo? Interior plywood is historically of birch (sweet sugary life supporting sap) bound by animal glues (edible fats). Modern ply uses inedible resins of various form and although birch is still the best furniture and aeroplane ply it will still be attacked whereas most cheaper plywoods use tropical semi-resinous timbers less susceptible to attack. BS1098 Marine Ply, for example, used timbers which are inedible to marine borers such as toredo worms and inedible waterproof resinous glues. But using marine ply for interior cabinet work is bit OTT... as is using natuarally resistant Western Red Cedar... except for clothes cabinets.. and WRC has its own allergic reactions with some people. The whole point of fungicides and insecticides to make the sugary cells inedible or not life supporting while oils/tars and waxes make it water resistant to stop it becoming life supporting... but poorly applied, it can cause 'soft-rot', a structural breakdown such as when using acid rich used engine oil as opposed to a proper exterior preservative.
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Old 14th Aug 2014, 9:21 pm   #24
Audio1950
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Default Re: Another woodworm question!

The gramophone arrived from France today, and sure enough, the motor board has about twenty holes scattered over it, but still seems strong enough for purpose, so will drench will fluid and fill the holes.
When I removed the speed control and handbrake from the motorboard, underneath were several holes packed solid with their gritty dust. Rather sad to think they spent all that time eating their way out, only to suddenly hit solid metal. All that effort in vain!

Barry
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