Got Worms?

Got Worms?

Subject: Identification and treatment of "wood worm" infestation.

At least eight families of beetles bore into wood, one of the most common being anobiids (furniture beetles). Larvae of the furniture beetle (Anobium punctatum) are more commonly known as woodworms. When holes in wood are first visible, infestation has been present for at least two years and as long as five years. In many instances, antiques are needlessly destroyed. Irreparable damage will not occur for a long time and would need to be neglected for many years after evidence of infestation is apparent.

Preventative measures should be taken to protect any valuable wood product against the larvae of furniture beetles. Examine any new piece thoroughly for signs of infestation and treat before introducing into your home. Do not store firewood inside your home only bring in what will be burned that day. Remove any wood product found to be infested immediately and treat. Treat all wood pieces in your home with woodworm oil annually. Woodworm oil should be applied in the spring prior to the furniture beetle larvae hatch and subsequent boring through to the surface of an infested piece. Caution should be taken when applying any product to valuable antiques, starting with a test spot is recommended. Apply a small amount of worm oil in an area not seen in the course of daily use and allow several days to dry in a ventilated area. Examine the spot closely for untoward effects in the character of the original finish.

The initial worm oil treatment should be thorough, examine the piece carefully for woodworm holes. Recent woodworm activity is indicated by fresh holes that are easily recognized by the sharp edges and a pale or clean appearance to the wood inside the hole. A fine powder produced by the insects boring activity known as frass will be present in the vicinity of fresh bores.

Generally seen in mid summer, wood beetles can be enticed to hatch and bore to the surface during any warm spell. Furniture beetles are approximately 1/8" long, narrow and reddish-brown in color with longitudinal ridges on the back. Search for the center of activity if a furniture beetle is discovered. Treatment is simple and effective.

Woodworm fluid, an oil-based insecticide, is injected into the wood worm holes using an injector with a sealing ring at the end of a fine nozzle and fitted onto a squeeze bottle. The insecticide is injected into the larval community, penetrating all infected areas, as well as uninfected areas for long term preservation. This process will end larval activity and make the wood unpalatable to future generations. Proper safety precautions for the application of worm oil include goggles, and chemical resistant rubber gloves

Corners, crevices, and woodworm holes should be treated with a prolonged squirt of woodworm oil. Pressure from this application may cause fluid to exit a worm hole at high pressure up to several inches away from the worm hole being treated, making eye protection essential. The application of worm fluid should be gradual and pressure
increased evenly while watching intently for the insecticide to exit at another location. Increase the pressure on the squeeze bottle until fluid begins seeping to the surface along the woodworm galleries. After treating all woodworm holes and crevices, distribute the excess fluid over surface of the surrounding wood. Remove any oily residue from the surface of the piece with a clean rag and allow the piece to dry for several days in ventilated area.

After this initial excessive treatment and subsequent drying, pack the woodworm holes with matching beeswax stopping. Although time consuming and tedious, this procedure will significantly improve the appearance of the piece and aid in detection of future woodworm activity. Annual treatment should include a thorough examination for new woodworm infestation, and precautionary injections of worm oil into crevices where wood Beatles prefer to lay their eggs.

Treatment for woodworms in a piece that requires repair should be done after the repair is made and all gluing and refinishing is complete because worm oil impedes the repair process. Fumigation should precede repair to prevent infestation of wood products in and around the work area. After the repair is complete, a worm oil treatment should be applied because fumigation only kills active larvae and worm fluid provides long-term protection.

In the case of extreme infestation and inaccessible locations, general fumigation of the home may be necessary. Whenever applying dusts, liquid insecticides, or fumigants, be sure to read instructions completely before starting application, and wear the required protective clothing and respiratory equipment.

Sources: Bennett, M. 1990 "Discovering and Restoring Antique Furniture." Cassell Publication, London, England Lippert, G. 1994 "Powder Post Beetles & Furniture Beetles" Kansas State University, Cooperative Extension Work, Publication MF1125, Manhattan, NY Marer, P. 1991. " Residential, Industrial, and Institutional Pest Control." University of California DANR Publication 3334, Oakland, CA.