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 Woodworm - Anobium Punctatum     
    Identification , Prevention , Treatment  and Restoration
                 for Violins and other stringed Instruments by Brian Roche.




Life Cycle

Food Sources

Detecting Infestation


1.   Introduction:-

Woodworm is a beetle which rains fear upon the population as it slowly disintegrates
the Violins, homes and furniture around us.

Woodboring beetle like the
Woodworm, encompasses many species and families of beetles whose
larval or adult forms eat and destroy wood (i.e., are xylophagous). Larval stages of some are
commonly known as

What is it ?,

Where does it come from?,

How do we protect our precious possessions from its unstoppable jaws?,

      In my day to day work as a Violin Maker, repairer and restorer I encounter the
destructive effects of this small beetle upon the Violin's, Viola's, and Cello's of the musical world.
Anyone who lives in an old house will see the tell tail signs of the beetles flight holes peppering the
rafters, doors, and even furniture.
In my work it is important to understand the insects
behavior and physiology in order to
effectively counter its devastating effects upon the violins I restore.

( You may find the following information helpful to you , but you use it at your own risk.)

( The Proper use of solvents and chemicals requires the use of Personal Protective Equipment, in
order to apply them safely.)

( For Personal Safety , when handling any chemicals or solvents ,

ALWAYS read the instructions for use, and take the appropriate manufacturers safety measures.

ALWAYS wear chemical Proof gloves, Safety Goggles, Protective clothing, and carry out the work
in a VERY well ventilated Room. )

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2    Anatomy:-

The common woodworm
(Anobium Punctatum) exists in 4 stages throughout its life cycle.
(a) Egg:-     The Eggs are approx 0.5mm long and 0.3mm wide

Larva:- The Larva is approx 6mm long- Cream to greyish white in colour, with a dark band over the mouth
                    area, Brownish mandibles and 3 pairs of legs. With a gold-brown head.- The body is covered in
Setae. ( Setae is a bristle).

Pupa:   A pupa is the life stage of the beetle undergoing transformation. The pupal stage is found
holometabolous insects, those that undergo a complete metamorphosis, going through
                   four life stages,   Egg, Larve, Pupa, Adult.

(d) Adult:- Cylindrical brown beetle 2.5mm  to  4.5mm in length- Identifiable with the humped (hooded)
prothorax, which covers the head.- Antenna with 3 segmented club.- The body is covered with
                   fine yellowish
setae and longitudinal rows of pits on elytra. ( Elytra is the leathery forewings of
                   the beetle)

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3     Habitat:-
(a) Wide spread in temperate climates and common throughout Europe.

(b) Exhibits a preference for damp timber and poorly heated rooms.
Humidity plays a
     very important part in the incidence timber infestations.
Relative Humidity above 65%
         leads to infestation problems.

(c) Common infestation in attics, cellars, kitchens, bathrooms and outhouses.

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4      Life Cycle:-  ( 4 Stages - EGG - LARVE - PUPA - ADULT )

(a) After mating , the woodworm beetle lays approx. 30 to 60 eggs, injecting them into the open pores of the
      timber, often open grain sawed ends. Eggs are never laid onto sealed or varnished surfaces. It is common
      for the beetle to lay the eggs down the old "Flight holes" , and tunnels , often well below the surface. The
      Eggs are laid singly or in rows of two, three or four.The Egg has a life of 14 to 28 days after

(b) The
Larvae live eating away within the wood for approx. 3 to 4 years. Symbiotic
yeast's enable the larvae to convert cellulose to protein in their gut, and  this
      process is assisted by a secretion of
enzyme which breaks down the plant cell walls
      to simpler sugars. Factors which contribute to the rate of Larval
      development are :(i)
Temperature: (ii) Humidity:  (iii) Nutritional value of timber.

(c) At the end of the 3 to 4 year feeding cycle the
Larvae pupate into an Adult beetle in chambers just below
      the surface.The
Pupa has a life of 21 to 60 days.  Pupation generally ends in Mid Summer or Easter, with
      the Adult beetles emerging to the surface and exiting the wood through the " Flight-Holes". The exiting
      urge is of such magnitude that they have been known to gnaw through paints, varnishes, plasters, sheet
      lead and Formica to the surface from the wood.

(d) The efficiency of the search for a female beetle  by the is male beetle is increased by the release of a sex
pheromone from the female body, which can be tracked by the male beetle.The female will mate 3 or more
      times during the course of the egg laying period.

(e) The Adult beetle lives for about a 4 week period,  during which time it lays its eggs
    . Both mating and egg laying can take place within the emergence hole
     (" Flight-hole") itself.Females shelter in flight holes periodically after emergence and hence there
          are many opportunities for  re-infesting  attacked wood.

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5    Food Sources:-

Woodworm prefers softwood, ( sawn rather than planed), and European hardwoods.

(b) It Likes
Coniferous and non-coniferous wood.

(c) They are found in aged timber with
starch present in the wood.

(d) The
Larvae eats and absorbs the cellulose only when it has been rendered
      digestible by
Fungi and microorganisms present in the wood itself.

(e) It will never lay eggs in
Starch Free wood.

(f) They are Seldom found in Fresh cut timber.

(g) Tunnels randomly but mainly in the
Grain Direction.

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6    Detecting Infestation:-

(a) Exit holes ("Flight-Holes) visible on the surface. Approx. 1 to 2mm in diameter.

(b) Expulsion of fine gritty powder (Frass) through the exit holes.

(c) Knocking sound from the wood during the mating season.

(d) The Gnawing of the
Larve in the wood.

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7    Treatment:-  USED ON NEW STOCKS OF WOOD.

For Personal Safety, when handling any chemicals or solvents,
                           ALWAYS read the instructions for use, and take the appropriate safety measures. 
                           ALWAYS wear chemical Proof gloves, Safety Goggles, Protective clothing, and carry out
                           the work in a VERY well ventilated Room.

(a) Prevention:

       (i)Application Time:-     Interrupting the life cycle by applying a chemical to the surface of the timber will
                                              kill off the woodworm beetle as it emerges and also prevents any visiting beetle
                                              from laying its eggs. Applying methods should contain a "Contact Chemical". The
                                              insect does not need to ingest the substance , only for the beetle to come in
                                              contact with it.
                                            - Application time for prevention substances is best in Spring , March to May,
                                              when the pupae is close to the surface of the wood, and the Adults are emerging
                                              from the wood.
                                            - The preventative substance penetrates the wood to approx. 2 to 6mm depth.
                                              Killing any surface layered Larvae or beetles coming into contact with it. Those
                                              Larvae remaining beneath the treatment zone will survive and continue to grow.

      (ii)New Wood : ( Violins )- Treat all new Wood before storing it with your Wood Stock.
                                                 - Generally apply 2 coats of woodworm preventative substance
                                                 -  Once the wood is treated Wax or paint the Ends. This will prevent the wood
                                                    from drying out too fast at the ends thus splitting and cracking.

      (iii) Practiced Methods of WoodWorm treatment on
            Violin &  stringed instrument making.

BORAX: (Preventative Measure ONLY) 
                                 -  Dissolve the
Borax powder in warm water. (Approx. 2 large tablespoons per Litre
                                -  Wet the wood completely , by submerging the wood in a container for
                                    2 to 3 minutes  (MAXIMUM).
                                - Remove the wood and allow to dry.
                                - The
BORAX is Odourless, Colourless, and safe to humans.
                                - Best results are obtained by applying Annually.
Borax is a natural mineral , mined from the ground, and has the lowest
                                  environmental effect when compared to the other methods of treatment.

              === :
PARAFFIN:    ( KILLS but does NOT Prevent Infestation.)
-  Apply by brushing the concentrated paraffin onto the infested surface of
                                   the wood.
                              -  Do Not Apply the
PARAFFIN onto Varnished or polished surfaces, as it
                                  may remove or damage these surfaces.
                              -  On NEW WOOD STOCKS the entire surface of the Wood should be
                              -  This method is used by Museums, as a method of protecting valuable wooden artifacts.
                              -  Best results are obtained by applying Annually.

Micro-Emulsions: (KILLS and Prevents Infestation.)
- Dilute in Water   25parts water to 1 part
                              -  On NEW WOOD STOCKS the entire surface of the Wood should be treated.
                              -  Do Not Apply the
Micro Emulsion solution to Varnished or polished surfaces as
                                  it may remove or damage these surfaces.
                              -  Apply once every 10 years.

WoodWorm Killer: (KILLS and Prevents Infestation.)
- Paint onto the surfaces of the Storage area for the removal of any
                                 woodworm already in the wood.  ( Spray into the corners)
                              -  Cover all total surface of the NEW wood stock, twice for good measure.
                              -  Do-Not allow the Woodworm killer to touch any varnished or polished
                                  surface as it may remove them.
                              -  Great care must be observed while using this substance , as it is
                                  hazardous to humans.
                              -  Best results are obtained by applying Annually.

Wood Preservative : (Preventative Measure ONLY)
- Paint stored wood with the preservative.
                               - Do Not apply the
Wood Preserative solution to Varnished or Polished surfaces
                                  as it may remove or damage these surfaces.
                               - Great care must be observed while using this substance , as it is hazardous to
                               -  Apply once every 3 to 5 years.

Pheromone Traps(KILLS Woodworm adult Beetles ONLY)
The History and Use  of Pheromone Traps   
  Locate close to the stored wood.
                               -  The
Pheromone trap will lure the Male Adult Beetles to there deaths.
                              -   Presents a minimal risk to Human Health.

(b) Removal:

        (i)  Anoxic
                         -  Treatment with NON-Toxic gases like
Nitrogen, Carbondioxide.
                         -  This method suffocates the insects , however it is a very slow process taking several weeks
this method is unreliable.
                         -  The use of
Fumigation with Toxic Gases presents too great a hazard to Humans.
                         -  High doses of
Gamma Rays, about 10000 R are necessary .This method is very
                            effective and quick.  This method is recommended by the
Hans Weisshaar book.
                         -  This  is the Best method available to treat Violins and Stringed Instruments as it
                             does not damage the Instrument.

                        - There are no harmful side effect's, or residue and kills the insects in all stages
                            of development.
                        -  However Great care must be taken to control the
temperature and humidity in
                            order not to damage the wood.

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8   References:-


The Strad magazine 1982 article “Woodworm in Violins” by Dennis Plowright.

B.V.M.A. Article “ Woodworm in the wood store”

Hans Weisshaar & Margaret book: “Violin restoration: A Manual for Violin Makers

Wikipedia:-  Picture of a Woodworm furniture_beetle

Images of the woodworm beetle.

Web site for anyone interested in wildlife and the countryside. Pictures

Kendal Bioresearch Pictures

Mc Gill Consultancy Ltd

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