The primary insect threat to wool textiles is the clothes moth, Tineola sp and in particular, the Webbing Clothes Moth, Tineola bisselliella. Damage is only caused by the larval stage of this moth, but an amazing amount of wool can be consumed during the larval stage. Adult clothes moths are small, about 1/8 inch long, usually a light grey to brown in colour and do not like light. When disturbed they will flutter for a few seconds and settle back down.
Moth larvae prefer dirty, soiled wool and will consume these areas of an artifact and may leave clean wool untouched. Wollen artifacts should be inspected at regular intervals, at least once a month and suspect artifacts isolated. Freezing infected artifacts at a temperature of -20C for 10 - 14 days is usually effective in killing moths in all stages of their life cycle. Following freezing, the artifact should be cleaned by brushing or vacuming.
Paradichlorobenzine or napthalene mothballs, crystals or flakes are effective in protecting against moths. They should not be in direct contact with the artifact. Mothballs in a cloth bag in a jacket pocket or suspended from the clothes hanger will provide protection as long as the jacket is in a closed environment.
A graphic example of improper storage, this First World War Canadian Tank Corps officers jacket has the appearance of being hit by several shotgun blasts, but was in fact severely moth infested. Large areas of material have been consumed by moth larvae. That the jacket was stored in a damp environment is evident from traces of mildew and that dye from the medal ribbons has migrated to the jacket. This jacket was said to have been stored by the original owner in a basement. The jacket was deemed not recoverable and was stripped of badges and insignia.
Detail of the left side and lower pocket. Evidently the pocket material was badly soiled as evidenced by the amount of damage to the bottom and side.
Detail of the underarm area. The major damage is where the wool was dirty and sweat stained.
Closeup of a Second World War detachable shirt collar. Note that the wool is heavily damaged but the cotton lining is untouched.
A Second World War RCAF wool lined leather flying suit heavily infested by moths. Although packed in an archival quality storage box by a museum, it was stored in an open environment with little humidity or temperature control. The box and it's contents had gone uninspected for at least 1 year.
The villains. Moth larvae were busily consuming the wool when the storage box was opened for inspection.
The result of improper storage and neglect. A great deal of the wool lining has been consumed. The small white specks are "frass" (moth larvae faecal debris). This rare flying suit was considered not recoverable and was destroyed.
Damage to artifacts by moths can be avoided or minimised by:
1.Inspection of the artifact immediately upon acquisition.
2.Freezing suspect artifacts.
3.Cleaning the artifact(including dry cleaning if the artifact is stable).
4.Storage or display in a proper environment.
5.Inspections on a regular basis.