Woodworms are the larval form of any wood boring beetle. They leave little trace when they enter the wood and their presence often goes undetected at this stage. They remain until they mature into adults and emerge through the characteristic exit holes. They attack most types of untreated wood and, under favorable conditions, can quickly reduce it to sawdust. The following steps will show how to eliminate woodworms.
Identify vulnerable wood. This varies by species but most species such as the common Furniture Beetle eats only dead sapwood timber. Older buildings that were constructed with untreated timber are especially susceptible to attack. Woodworms thrive in timber with a moisture content greater than 20 percent.
Locate woodworm infestations. The exit holes are circular and usually 1 to 2 mm in diameter but may be as large as 5 mm across. Recent activity may be identified by fine dust around the holes.
Block the holes during the winter with painting with an emulsion coat or applying masking tape. Check for holes in the spring to see if the infestation is current.
Control infestations by thoroughly applying a residual insecticide containing 0.1 to 0.2 percent permethrin in the spring. Repeat the treatment each year until there is no more new activity. Treatment of house timbers usually requires professional fumigation or even replacement of the timbers. Kill the adult beetles with aerosol insecticides or smoke generators.
Apply a commercial wood preservative. These chemicals have solvents that penetrate the wood and may be brushed or sprayed on. Mixtures of wood preservatives and insecticides are commercially available.