Innovation: Woodworm's fatal attraction

HOUSEHOLDERS will be able to do annual checks for woodworm with a DIY kit to be launched next spring. The kit will also tell prospective house purchasers if the characteristic holes in wood are old and can be ignored, or if they are the result of live infestations.

Woodworm is a common pest accounting for between 70 and 80 per cent of all boring insect wood damage in the UK.

The kit uses a synthetic version of the pheromone, stegobinone - a compound released into the air by female woodworm to attract male partners. When the synthetic pheromone is released, males are attracted to the source and are then trapped on a sticky base.

The possibility of using stegobinone to attract and trap males was demonstrated and patented by scientists in Oxford University's Zoology Department in the late 1980s. But the mass extraction of the compound from female woodworm is not commercially viable - it would take 100,000 insects to produce a few milligrams.

The pheromone has a very complex structure, so it has taken the biotechnology company Oxford Asymmetry several years to develop a synthetic version. The company is working with Agrisense in Cardiff, which specialises in pheromone traps, to commercialise the development.

Oxford Asymmetry specialises in chiral compounds. These are chemicals that exist in two different molecular forms that are identical apart from being mirror images of each other. The left- and right- hand forms of chiral compounds often have very different properties. For example, the difference between the smell and taste of an orange and a lemon depends on whether the molecule limonene is right- or left-handed. So it is with stegobinone, where one form attracts males and the other repels them.

Oxford Asymmetry's managing director, Dr Edwin Moses, says this made the job of producing a pure synthetic version much more difficult. Any contamination meant the males were initially attracted to the source of the pheromone but turned tail when they sensed the repellent form of the molecule. The company is trying to produce the repellent form to see if it could be used to pre- empt woodworm.

The synthetic version was as effective as naturally occurring stegobinone in trials carried out in a number of buildings across the country this year. A single trap attracts males over a range of 10 to 20 metres, so one could be used to assess the timbers in the roof space of a house.

The stegobinone lure will first be sold as a diagnostic test for woodworm. Insecticides can then be applied if the worms are present. There is currently no way of telling if woodworm holes are old and can be ignored or are evidence of live infestations. So the wood is treated to be on the safe side.

Dr Moses says the traps could eventually replace insecticides as the means of controlling the pest. Either the males could be caught en masse in the pheromone trap, leaving the females without mates and unable to reproduce, or the pheromone could be sprayed around the infested area, inciting confusion in the males, and putting them off the scent.

This approach is already used in agriculture where pheromones are replacing chemical insecticides.

'Conventional treatment of woodworm is a reactive, non- specific and costly process,' said Dr Moses. 'Stegobinone traps offer significant advantages in terms of cost and safety.'

(Photograph omitted)