Holes in wool garments have three distinct causes, each with a different prevention mechanism: moth larvae, enzyme-based detergents, and mechanical damage from washing. Understanding which is responsible - and why - is the starting point for effective prevention.

Cause 1: Moth Larvae

The common assumption is that moths eat wool. The more precise answer is that moth larvae eat wool - specifically the keratin protein that wool, silk, and other animal-derived fibres are composed of.

Adult clothes moths (Tineola bisselliella) do not eat fabric. They lay eggs on natural fibre garments, and it is the larvae that hatch from those eggs that feed on the fibre, creating irregular holes as they move through the fabric.

What attracts moth larvae to wool:

- Keratin is their primary food source - natural protein fibres are far more susceptible than synthetics

- Garments with residual body oils, sweat, or food stains are significantly more attractive than clean garments - the organic residue provides additional nutrition

- Dark, undisturbed, warm environments - the typical conditions inside a closed wardrobe or drawer - are ideal for egg laying and larval development

- Larvae are most active from spring through autumn, but can cause damage year-round in heated indoor environments

A secondary pest: silverfish also damage wool, though differently. Rather than consuming fibre for nutrition, silverfish feed on surface starch and organic residue, weakening the fabric structure and causing surface damage that can develop into holes under stress.

Cause 2: Enzyme-Based Detergents

This cause is less widely known and is responsible for a significant proportion of the small, scattered holes that develop in wool garments over multiple washes.

Many laundry detergents - including those marketed as natural or eco-friendly - contain proteolytic enzymes, most commonly protease. These enzymes are designed to break down protein-based stains: blood, sweat, egg, food residue. They are effective, biodegradable, and environmentally preferable to synthetic surfactants for most laundry applications.

The problem is that protease cannot distinguish between a protein stain and a protein fibre. Wool and silk are both keratin-based protein fibres. Repeated washing with protease-containing detergent progressively breaks down the fibre structure of wool garments, creating small holes - typically appearing after multiple washes rather than immediately, which makes the cause difficult to identify.

How to identify enzyme damage: holes caused by enzyme breakdown tend to be small, multiple, and distributed across areas of the garment that receive the most friction or agitation during washing. They differ from moth damage, which tends to be more localised and irregular.

How to avoid it: check detergent ingredients before using on wool or silk. Avoid any detergent listing protease, amylase combined with protease, or simply "enzymes" without specification. Purpose-formulated wool washes - such as those using soap-based rather than enzyme-based cleaning mechanisms - are safe for repeated use on protein fibres.

Cause 3: Mechanical Damage During Washing

Wool knits are susceptible to snagging on other garments, zips, fasteners, and the drum of a washing machine during agitation. A single snag on a loosely knitted garment can pull fibres and create a hole or run that worsens with subsequent washing.

High agitation cycles also stress the fibre structure of wool over time, even without visible snagging - particularly at seams and high-friction areas like underarms and cuffs.

Prevention:

- Use a mesh laundry bag for all wool garments in the machine

- Fasten zips and turn garments with metal hardware inside out before washing

- Use the wool or delicate cycle only - never a standard or heavy cycle

- Hand wash knits rather than machine washing where possible

How to Store Wool to Prevent Moth Damage

Storage conditions are the primary variable in moth prevention. The goal is to make your wardrobe inhospitable to egg laying and larval development.

Wash before storing

Clean garments before putting them away for the season. Moth larvae are significantly more attracted to garments carrying body oils, sweat, or food residue. A clean garment stored correctly is substantially less vulnerable than an unwashed one.

Use cotton storage bags

Moths avoid cotton and synthetic fabrics - their interest is in wool, silk, cashmere, and other keratin-based natural fibres. Storing wool garments in sealed cotton bags creates a physical barrier that prevents moths from accessing the fabric to lay eggs.

Use cedar or lavender - not mothballs

Cedar and lavender both act as natural moth deterrents. Cedar contains oils that repel adult moths; lavender's strong scent similarly discourages egg laying. Place cedar blocks or lavender sachets inside each storage bag.

Conventional mothballs contain either naphthalene or paradichlorobenzene - both classified as possible human carcinogens, both requiring ventilation to off-gas safely, and both leaving a persistent chemical odour on garments. They are not necessary and are not recommended.

Keep the wardrobe open and disturbed

Moths prefer dark, undisturbed environments. Regularly opening and airing your wardrobe - and keeping it reasonably well-lit - discourages egg laying. Rotating garments so nothing sits completely undisturbed for extended periods is an effective passive deterrent.

Avoid damp storage

Moisture accelerates both moth activity and mildew. Store wool in dry conditions, and ensure garments are fully dry before folding and putting away.

What to Do If You Find Moth Larvae

If you discover moth larvae or eggs on a garment - small, grain-like eggs or tiny cream-coloured larvae - the most effective treatment is freezing.

Freezing method:

1. Place the affected garment in a sealed plastic bag, removing as much air as possible. Sealing is important - it prevents condensation forming on the garment when it is removed from the freezer.

2. Place in the freezer for a minimum of 72 hours. This kills larvae and eggs at all developmental stages.

3. Remove from the freezer and allow to return to room temperature before opening the bag.

4. Inspect the garment and brush off any dead larvae before washing or airing.

Check other garments stored nearby - moths move between items, and finding larvae on one garment suggests others may be affected.

Hole Prevention: Summary

For specific care instructions for your Nui garment, check the care label or the product page. Explore the Nui merino collection.