Wool Moths - Twin Willows Farm

Wool Moths
by Pegg Thomas

The most dreaded of all insects from a spinner’s point of view is the moth. They are nasty little monsters that infect and infest our precious fibers. They leave behind eggs to hatch into wiggly little worms that eat our fibers. UGH!

Some facts to know are:

1. there are 3 types of damaging moths
   the webbing clothes moth
   the casemaking clothes moth
   the carpet or tapestry moth
2.   the lifecycle of a moth includes four stages, egg, larvae, pupa and adult
3.   moths do not eat fibers, the larvae (worm-like stage) do
4.   female moths rarely fly until after their eggs are laid
5.   moths seen flying around the house are generally male
6.   eggs can hatch from 4 to 30 days after laying, depending on temperature and humidity
7.   dry cleaning kills moths in all stages of their life cycle
8.   freezing for at least 3 days kills the larvae
9.   cedar, lavender, pennyroyal and other natural repellents do not kill the moths
10.   moth larvae cannot survive on clean wool alone

The first sign of a moth problem is typically seeing little “cigar” like things in the wool or on a garment. These are the cocoons of the pupa stage of the moth’s life cycle. The color of the cocoons will depend on the color of the wool the larvae consumed. Holes may be seen or the wool or garment may have a gritty feel to it. That “grit” is the tiny eggs. Pulling the wool apart over a piece of dark paper will usually allow the eggs to drop through and be seen clearly.

The best way to avoid moth problems is to store only clean wool garments and washed unspun wool. Moth larvae need more than clean wool to thrive, they require the nutrients found in urine, sweat, lanolin, and food residues. Wash, brush and air out your wool garments before storing away for the summer.

The best way to treat a moth problem in clothing is to thoroughly clean the infected garments and the storage area. Dry cleaning is the best for killing the moths at any stage of life, but is not recommended for all garments. Total immersion in hot soapy water is also good. Vacuum the storage area carefully with attachments to get into all the corners and crevices. Completely clean the vacuum afterwards to avoid spreading eggs. Chemical treatments for clothing are not recommended, but some chemicals can be used on the storage containers depending on the material of the container. Read all labels carefully.

Unspun wool found infested should be sealed up in a plastic bag and frozen for at least three days. Allow wool to return to room temperature and wash in hot, soapy water. Rewash if the fleece was clean. There will probably be eggs in the plastic bag, so care should be taken in transferring the wool from bag to washing, and the bag removed and burned if possible. After thoroughly drying, again place in a clean plastic bag and freeze for another 3 days. Be aware that eggs may fall out of the now clean wool and carefully clean the surface the wool dried on. Freezing will not kill moth eggs. However, the hot water wash and drying will allow any surviving eggs to hatch and refreezing will kill off any new larvae. Therefore, your wool should now be fully cleaned of moths.

Moths are not a death sentence for your fibers or garments. Catching the problem early and quickly taking action can prevent major damage. Small holes can be patched more easily and slightly chewed wool or roving won’t affect the finished yarn. Moths are part of nature and can’t be totally eliminated so handspinners need to be aware of them.

Twin Willows Farm - Wool Moths