This Collections Care document has been produced using information from our Conservation Development Officer, Helena Jaeschke.

This resource will provide information on identifying and dealing with case-bearing moths in your museum collection.

Case-bearing Moth Pest Information Sheet

Size 

Adult 8-10mm, larva up to 10mm long

Favourite Food

Larvae eat animal protein fibres such as wool, silk, fur and feathers. May eat dead animals especially birds.

What to look for

Larva – Dark brown head and cream coloured body, usually inside a case made from fibres, so can be camouflaged on the object. 

Adult – Silvery brown moth with fringed wings, often with two or more darker spots and a fuzzy golden head. Long, thin antennae. Often walk rather than fly.

The Case-bearing Clothes Moth is only a centimetre long, with slim, silky wings and a tuft of golden hairs on its head. 

Adults: Similar to its relative, the Webbing Clothes Moth, but can be distinguished by the colour which is more greyish-brown than golden and the presence of two or more darker patches on the wings. 

Larvae: Sometimes seen crawling up walls, dragging their fuzzy fibrous case with them. The case is made using fibres chewed from the object they were feeding on, so can be camouflaged. 

The adults may be attracted to a museum by the presence of dead animals such as mice or birds in attics or roof spaces. Having stripped it clean of fur, feathers and skin they may then invade the rest of the building looking for more animal fibres. They can tolerate damper areas than Webbing Clothes Moths.

The adults generally appear in spring but with increasing warmth they can have up to four life cycles a year and you may see them throughout the summer and autumn. 

If you spot the adults or larvae in the museum, crawling up walls, stuck in traps or fluttering near windows, it is vital that you take action to find out what they have been eating and if you have a colony that is spreading. 

Top tips:

  • Don’t forget – other moths may also be damaging the collection. We have more details on other pests, including our online resource pages.​
  • If you are unsure about how to deal with any pests in your collection or store, contact a conservator (or Conservation Development Officer in the SW) for advice.​

Actions

  • Be scrupulous about housekeeping – empty bins daily and make sure food residues are cleaned up.
  • Have traps in all areas, especially where people hang up coats and bags – they can bring moths in unknowingly (or carry them home!)
  • Deep clean areas where there may be an infestation – move all boxes, vacuum floors and wipe shelves. You can use a museum-suitable permethrin-type pesticide like Constrain to spray in cracks in walls, floors, under skirting boards but not on objects.
  • If you find infested objects, pick off any live pests you find, then isolate the objects by wrapping them in acid-free tissue and then in polythene sheet and sealing ALL the edges with parcel tape. 
  • Contact a conservator (or the CDO if your museum is in the South West) for treatment advice, quickly! 

Download the below resource for information on case-bearing moths in your collection.