Moths. You’re probably scared of them. And you should be.
It’s not the adults, but the moth larvae that eat our precious wool. Did you know that one female can lay up to 50 eggs at a time, and the resulting larvae can live for up to 50 days, eating every day? Horrifying.
There are different types of moths. The ones we’re worried about are called Tineola bisselliella. [Editor’s note: Tap the link if you live a blessed life and have never seen one of these pests. We used beautiful old entomological charts as featured images here because it seems like a bad omen to post the real critters.]
- The adults: about the size of a grain of rice, a shiny tan or gold color.
- The larvae: creamy-white worms with dark heads.
- The eggs: little black or white lumps, about the size of a pinhead, dotting the yarn or fabric.
- Yarn that’s broken in multiple places, and the breaks are rough or fuzzy.
- Multiple large-ish, rough-edged holes in fabric.
- If it’s a sock, or other item that gets worn a lot, don’t panic just yet. If the fabric around the hole is thinning, it’s a sign of wear and tear. (Consider learning more about reinforcing your socks.)
- If it’s a single small hole, it might just be that the yarn got caught and broke—look for pulls in the fabric around the hole. Moths don’t tug on the yarn, they just eat it.
- If it’s where yarn was joined, it might just be an end that’s come undone. Breathe easy and perhaps review my guidance how to weave in ends.
What to do if you see danger signs
Step 1: Get everything that’s directly affected, or has been stored with the affect items, outside. Immediately.
Step 2: Sit down and cry. (The next step will be painful.)
Step 3: Get rid of it. Anything with obvious signs of larvae or eggs, or with multiple breaks or holes needs to go. And stuff that’s been stored with infested items has to go, too. Sorry, but you can’t necessarily detect the eggs when they are very new, and you just can’t guarantee you’ll get it clean.
You can clean items, but that requires extreme heat or extreme cold. For cold, you need industrial-freezer or winter-in-Minnesota temperatures—below minus 20°C/0°F. (And there are reliable reports of the larvae not dying in the cold, just becoming dormant, the little monsters.) For heat, use a professional steamer, or get them into a washing machine with water least 55°C/130°F. (Some knitters have successfully used an oven for this, but that has its own risks.)
Step 4: Thoroughly clean the storage containers you were using, with soap and hot water. Dust and clean cupboards and shelves, with a damp cloth and a cleaning solution. Vacuum carpeted areas.
Protect your stash and your woollies
It’s a good idea to inspect your stash and woollies a couple of times a year, outdoors if possible. Let everything get a good airing, ideally in the sunlight. When the adults are looking for a place to lay their eggs, they look for dark corners where they aren’t likely to be disturbed. Shine a light, move things around, shake things out—disturb the beasties!
Use air-tight plastic boxes and bags. Isolate things. You don’t know how yarn was stored before it came to you, so I recommend a quarantine policy—each set of skeins goes in its own bag. If yarn does bring moths into your home, you only lose those skeins.
Woollies and FOs
Moths eat protein, so they’re after protein fibers like wool and silk, but they’re also after other types of protein that might gather: food crumbs, discarded skin cells, sweat, the oils from your hair and skin. (Ick.)
Therefore, items should be clean before they’re put away for any length of time. Like, wash them. And again, I recommend air-tight storage. Things won’t get smelly if you put them away clean and dry. When you unpack, let items air out for a day or two—again, outdoors if possible—before putting them into your wardrobe.
For items in regular rotation, store clean items together and keep items that you’ve worn but aren’t ready for a wash elsewhere.
In the MDK Shop
Products to help
Keep pheromone traps in your closet and yarn storage areas. They are non-toxic and odorless; they attract the adult moths and stop them from laying eggs. Make sure they’re specifically for clothing moths, and change them on the recommended schedule.
Old fashioned moth balls smell terrible and they’re toxic. They’re actually banned in some parts of the world. Don’t use them.
On cedar, eucalyptus, lavender, other scents: These are deterrents. Moths don’t like these scents, but you have to keep the scents at a decent concentration and replace sachets and blocks because their scent will dissipate over time. One strip of cedar just isn’t strong enough to keep an entire shelf of yarn safe. Sorry.