Why does cashmere get holes?

The appearance of mysterious holes in cashmere is almost always caused by one of two factors: biological attack (insects) or mechanical failure (friction).

As a manufacturer, it is crucial to help your customers distinguish between these two, as “moth holes” are often blamed for what is actually “friction damage” from daily wear.

Here is the technical breakdown.

1. Biological Attack: The “Invisible” Enemy

This is the most common cause of holes that appear after a garment has been in storage.

The Culprit: It is rarely the adult moth you see flying.¹ The damage is caused by the larvae of the Clothes Moth (Tineola bisselliella) or the Carpet Beetle.²
The Diet (Keratin): Cashmere is made of animal hair, which consists of a protein called keratin.³ Moth larvae feed exclusively on keratin.
The “Attractant” (Vitamin B): Larvae cannot hydrate themselves; they need moisture and Vitamin B to survive. Human sweat, skin oils, and microscopic food stains are rich in Vitamin B.
- Key Insight: Moths will almost always target the dirty spots first (underarms, cuffs, neckline) rather than the clean fabric. This is why “washing before storage” is the single most important prevention step.

2. Mechanical Failure: Friction & “Short Staple” Weakness

If a customer claims a hole appeared after only a few wears, it is likely mechanical.

Tensile Strength: Cashmere is warm but structurally weak. To make it soft, the yarn is often spun with a “loose twist.” This reduces tensile strength compared to a tightly twisted Merino wool.
The “Desk Job” Hole: A common phenomenon is holes appearing near the stomach area. This is caused by the soft cashmere rubbing against a desk edge, a seatbelt, or the metal button of a pair of jeans (the “zipper friction” point).
Staple Length: Cheaper cashmere often uses shorter fibers (under 30mm). These fibers slip out of the yarn twist easily. When the garment pills, and the customer pulls the pill off, they are physically thinning the fabric. Eventually, this spot becomes so thin it disintegrates into a hole.

3. How to Diagnose the Hole (The “CSI” Approach)

You can tell the difference by looking closely at the hole itself.

Feature	Insect Damage (Moths)	Mechanical Damage (Friction)
Edge Appearance	Jagged / Chewed. The edges look irregular, like they were nibbled.	Clean / Frayed. The thread has snapped cleanly or unraveled.
Location	Random spots, often near stains, underarms, or chest.	High-friction areas: Elbows, stomach (button rub), cuffs.
Surroundings	You may see “webbing” or tiny sand-like pellets (frass/droppings) nearby.	You will often see thinning fabric or heavy pilling around the hole.
Timing	Appears after storage (Summer/Autumn).	Appears during active wear (Winter).

4. Prevention & Care Strategy

For Moths: The only true defense is to starve them. Store cashmere only after it has been washed. If there is no sweat/food residue, the larvae are less likely to survive on the dry fiber alone.⁴ Cedar blocks and lavender help repel adults, but they do not kill larvae.⁵
For Friction: Encourage customers to use a fabric shaver rather than pulling pills by hand. Pulling a pill drags the fiber out of the core yarn, weakening the structure. Shaving it cuts the excess without disturbing the structural integrity.⁶

Summary

Small, random holes after summer storage? It’s moths/larvae.⁷
Holes near the waist or elbows during winter? It’s friction against a belt, desk, or zipper.