I Got Wool Moths or Beetles! Now What?!
i have a very important update! (June 2022)
Wool moths can eat through plastic, even freezer bags.
On the other hand, it would appear that they do not eat through paper.
I will come back and fix some things in this post with better advice on how to protect your wool based on my personal discovery, with photos for evidence this time (because I did take pictures).
Right now, I’m in a bit of a time crunch finishing up our homeschool year and getting ready to start the next, but updating this post is a priority as soon as I’m able to get to it. Since I know this is one of my more popular posts, I want to make sure that the information in here is as accurate as possible (otherwise I would’ve just written a new one, but that would be too confusing).
In the spirit of Halloween month, I thought I’d start off with a horror story…
In a dark, dark wood, there was a dark, dark house.
And in that dark, dark house, there was a dark, dark room.
And in that dark, dark room, there was a dark, dark closet.
And in that dark, dark closet, there was a dark, dark box.
And in that dark, dark box was a….
PILE OF DUST, where there used to be wool.
As well as some eggs, larvae, wool moths, droppings, etc…
Wool moths, also known as carpet moths, clothing moths, etc., are one of those taboo topics in the fiber world. They happen, but people rarely want to admit that they’ve had an infestation, or are currently dealing with one. Much like any bugs really… Except maybe butterflies. I don’t think anyone would be opposed to an infestation of butterflies.
The fact that it’s talked about as unfortunate, isolated incidents that happen rarely rather than admitting that you’ve seen them here and there is dangerous, especially to new fiber folks. One, they don’t know how to handle it if they see it. Two, if they do have to deal with it, they are afraid to admit it. Look, I get not wanting to admit it. Some people still have the incorrect attitude that it implies you’re somehow untidy, but this attitude ends up with the tidiest people securing their stash in plastic bins (which are not air tight, by the way, unless you tape them up), maybe setting it aside if life gets busy for a while thinking it’s safe, then opening the bin up to have wool moths flying out and a pile of dust where their fiber used to be. And the other option, space saver bags? That’s not good for wool, because wool holds moisture. Even if it feels dry to the touch, there’s a natural humidity in the air to some degree, and it will absorb that. It needs to breathe. It’s fine if it’s for short periods, but long periods, you could end up damaging your fiber. Would you stick a damp towel in a bag in the closet for a few months? Side note: don’t use the space savers for wool sweaters either, they will crease your sweaters. I read that for the amount of time you keep one in the bag, you need an equal amount of time to let it air out and return to its original shape. If you store them for half the year, you’ll need the other half to let it fluff back up.
So let’s get a few myths out of the way, some of which I’ll get into in my post:
Myth: only dirty, untidy people deal with wool moths - even museums deal with them
Myth: wool moths are rare (see above)
Myth: if I store it in a plastic tub, I’m safe
Myth: storing my wool in plastic bags is safe (maybe if you double bag it, but I read somewhere these f-kers can chew through thin plastic)
Myth: randomly placed cedar chips and lavender satchels will keep it safe, or keeping it in a cedar chest
Myth: newly purchased wool is clean and safe from moths, and I can just throw it in my stash
Myth: freezing them will kill them (oooh, I know this one’s going to have a few people biting their nails right now)
Myth: the moths and larvae attacking your grain products are the same as wool moths (they look very similar, but they’re not - that’s a separate problem)
My point is, even the cleanest, tidiest people in the world can get wool moths, especially if they tuck their wool into a bin to forget about it for a few months to year or more…
I want us to talk about wool moths in a matter-of-fact way, because they happen. They happen more than people are willing to admit.
I’d even be willing to bet that the majority of people who have been working with fiber for any decent length of time have either dealt with them here and there, or probably will at some point in their career or hobby. Even if they don’t want to admit it. If they’re adamant that they’ve never dealt with them, they just jinxed themselves.
I also want to define the word infestation. Seeing a single wool moth or a larvae here and there or some eggs is not an infestation. I call that a warning, and while you have some work ahead of you, you still have a chance to save your wool. I define an infestation as opening up a container of wool, seeing some wool moths freak out and try to get away, and seeing a pile of dust where there used to be gorgeous, probably expensive, top or roving. An infestation is so bad, there’s no saving it.
Yes, I have dealt with wool moths! I have had a raw fleece that I didn’t get to in time, and it ended up infested. This is why we never ever ever store raw fleeces in the same space as our clean, scoured, dyed wool supply - keep it out in the garage, another room, anywhere else but where you keep your clean stuff. I have had wool moths eat their way out of felted exchange gifts. I have had them get into a tiny pile in a corner of a shelf that had been missed and forgotten long enough for them to move in and do some damage. I have not had them attack/destroy my main stash yet, because of the preventative measures I take to keep any potential infestations in check. In my experience, the pattern has been anything that was forgotten and kept in a dark space is the stuff they went for, especially if it was dirty, not the stuff I had sitting out in the open on my shelves. Just like an old wool sweater packed away for winter.
Now that we got all that out of the way…
If you see evidence of wool moths, it is not the end of the world!
No, you don’t have to go and toss all your stash. I mean, you will want to toss anything that’s in really bad shape (an infestation, yeah, you’d wanna toss that), but if you are working pretty regularly with your wool, and/or checking it pretty regularly, it’s not going to get that bad. Chances are, if you’re using your wool, they’re going to be less likely to go for it. Wool moths tend to go for things that are forgotten. A plastic tub or bags are just a false sense of security, and enable you to “forget” about it for longer periods of time - don’t do this.
But before I get to all the things I do to keep my stash clean, let’s go over what you’re looking for, first. Unfortunately I don’t have any photos of them for ya, but I have come across them and want to help you know what to look for. If you would like to see photos, the University of Kentucky’s entomology site is a good source. Click here for wool moths, and click here for carpet beetles. How do you know if it’s one or the other? If it’s carpet beetles, you’ll likely see tiny beetle exoskeletons nearby or even still stuck on the item (I’ve come across them on clothes).
If you’re wondering why the H-E-double-hockey-sticks do these creatures even have to exist in nature - they actually help play a vital role in the decomposition of fur and carcasses in the wild, because they can digest keratin. We just don’t need them digesting the keratin of our fiber or clothing, because we’re still using it, thankyouverymuch. They go for any keratin, not just sheep’s wool. They can live off hair, lint, etc. If you have pets that shed, and there are some things you don’t quite get to vacuuming or dusting, they will be interested in that too. If you have wool rugs or blankets, they’ll go for those. They can be in your vents. Basically anything that’s made from the hair of any animal (including human). This is why it’s so easy to end up with them. This is also why freezing them won’t kill them* - if you think about why they exist, and the fact that they exist in nature even up in cold parts which have freezing temperatures for a solid few months, how would sticking wool in the freezer for a few weeks take care of the problem?
*You may notice that certain sites like the museum one and the ones I linked above mention freezing. Pay attention to the temperature required to kill them. They have freezers that can reach minus 20 degrees Fahrenheit - and they need to be kept at that temperature for a week. The freezers we use at home are usually kept around 0, give or take a few degrees. Unless you have a freezer capable of reaching these low temps, all you’re going to do at home is put them into hibernation, just like they would outside in the winter months. The best you can do at home is heat.
Wool moth lifecycle and what they look like
Eggs are probably the biggest pain to deal with, because they are incredibly tiny. Remember those microbead pillows that were really popular for a while? Did you ever have one that burst on you, or that maybe had a bad seam? That’s what the eggs look like, but the size of a grain of salt. If there’s a bad infestation, you’ll see a ton of them close together, so they’ll be easy to spot, but it’s that lone egg or two that can hitch a ride. These take about 4-10 days to hatch.
Next are the larvae. Believe it or not, it’s not the moths that do the damage, it’s the larvae. Initially the larvae are microscopic like the eggs they hatch from, and in some cases they will spin tiny matts which they hide in and feed out of. How long they remain larvae depends largely on the conditions of the environment, can go through anywhere between 5-45 molts, and this can last anywhere from a month to two years. What you’ll be looking for here, is if you have roving, or even top, or even batt that you know is a fairly smooth batt and should be without nepps, and you see teensy little matted fibers? Those could possibly be larvae. Especially if you’d never seen them in there before, and especially if the fiber around it seems broken or short. The older larvae will be much easier to spot - they will at this point have bore quite a hole in whatever it is they’re living on. There are actually two types of wool moths: webmaking and casemaking. If it’s a casemaking one, you’ll find long, skinny tubes that they’re living in, in the same color as whatever they’re munching on. The webmaking ones you’ll see nekkid, at which point they look like tiny white caterpillars with dark heads. If I had to paint a picture, I would compare it to a very skinny grain of rice. The larvae can reach up to just over a centimeter in length before the pupate (so you really can’t miss it). Pupating takes another 8-10 days once they reach that stage.
The moths themselves just lay the eggs (they’re not the ones doing the damage), and if you see any flying about… they’re probably not clothes moths, but pantry moths. Clothes moths suck at flying, they prefer scuttling about, and prefer dark areas. They’re very shy and secretive. The way you might see them is if you move some furniture or open a box or a bag of wool and see one freak out. The moths are easy to identify, about a centimeter in length and they have a shimmery khaki color.
Carpet beetle lifecycle and what they look like
I don’t think there’s any way you could spot the eggs of these things - at least the eggs of the wool moth are visible to the naked eye (if you have decent vision), so I’ll go ahead and skip this part. Nobody’s looking at their wool under a microscope.
The larvae look like miniature alien type creatures. There’s really no other way to describe it - the body is segmented and fuzzy, and the color is brown and tan. You’ll probably be more likely to recognize the presence of these creatures by finding the exoskeletons from their molts.
Adults look like little oval bugs and have a mottled brown/tan/black color.
Update: There’s another resource here for carpet beetles with photos and more details than I provided here that also has links to products with natural repellents. While I would not recommend spraying any of these repellents directly on your wool, projects, or art, you can certainly try using these when you do your housekeeping to try to prevent them from getting to your stash in the first place. Prevention really is the best first step, but I’ll show you what to do once you do find them in the stash (and then once you clean everything up, continue using any preventative measures).
preventative measures
I’m using the word preventative loosely here, because what you’re really doing is preventing a full on infestation. You’re not preventing them from showing up in the first place. At most, you’ll increase your chances of staying moth-free.
Here’s your to-do list as a fiber artist. You need to do this ONCE A MONTH, ON THE DOT.
Go through your entire stash (and art!) and check it thoroughly.
Clean any wool processing tools thoroughly.
Deep clean any area you work with fiber.
Replace air filters as needed.
Once-a-year if you have the money, hire someone to vacuum your ductwork. Also a good idea anyway if you suffer from allergies. I’ve seen coupons for these services in those money mailers here and there.
Checking your fiber stash:
This isn’t to get rid of them, it’s to catch any that snuck in before they have a chance to become an infestation and turn your stash into dust. Remember how I said the larvae take anywhere from a month at best to two years before they pupate? If you do this once a month without fail, and catch any larvae, all you really need to do is pick them out and toss them (we’ll also deal with any wool where you find them in a minute). They won’t get to the point of becoming a moth to lay more eggs. If you’re lucky, and it was just a lone egg or few that made its way into your stash, that’s the only one you’re going to have to deal with.
My process involves having a vacuum at the ready, a clean, smooth, dry surface, preferably something darker than white so you can spot any eggs and help you see through the wool. If your eyesight isn’t great, a large magnifying glass might help. I personally use the bare, wooden floor, but you can put a black trash bag down on an elevated surface if you need to sit in a chair. I pull my wool out one by one. Batts get split up into manageable sections and spread out spider-web thin along the floor. The reasons for this are two-fold. If a wool moth had gotten to your wool an laid some eggs, some of the eggs will fall out of the wool and onto the surface beneath. Also, spreading it out spider-web thin will allow you to better see any eggs or larvae in the wool. Pick those out and set them aside to be vacuumed up (they won’t run off). Gently peel the wool up off the floor and look for white little beads - those are eggs. Vacuum the floor, flip the batt over, and do it again. Don’t rush this process. If you see any presence of wool moths, I’ll explain your next steps in the section below on how to get rid of them. Vacuum the surface between each check so you don’t accidentally move them from one batt to the next.
Roving gets unwound. I spread the roving out, set it on the surface, and look it over, remembering to flip it to check either side. Do this all the way to the end. You can wind it back up when you’re done. Locks, same thing, maybe not spread them out to break up the lock, but definitely take a good look at them, shake them out over a dark surface and check for eggs.
I think doing this anyway is good for the fleece, giving it a bit of air to breathe, unwrapping it, etc. Helps to fluff it up.
Wool processing tools:
If you process fiber under any capacity, you also need to make sure you clean your carders regularly. I know, picking fibers off of carders is a pain, especially the lickers. However, if you didn’t quarantine your fiber, and there was an egg or two that slipped in, you can easily cross-contaminate any other batts that you make. Spinning wheels get lint in the crevices, so make sure you vacuum those.
You can use pet brushes to get any wool off your carders and lickers first before spraying it down. Honestly, you should be doing this anyway after carding, and include this in your clean-up process. Leaving wool sitting on carders is an invitation for them to move in, especially if you’re not planning on carding for a while… remember what I said about dark spaces and forgotten wool? The space under the carder and in-between is nice and dark.
Next, you’ll want to take a vacuum to the carder and vacuum thoroughly. Take the carder off the table and vacuum the lint that’s collected underneath. If you have wool that got caught inside between the drum and the wall of the carder, try to pick that out if possible, or grab some wrenches to take it apart and remove it. Pay attention when putting it back together to make sure it’s properly spaced, as carders allow for you to make minor adjustments. You don’t want the teeth rubbing against each other when it spins, but you also don’t want it too far apart that the licker doesn’t help put the wool on the carder.
You can clean your tools with a solution of diluted dish soap. In the case of carding wool in the grease, you will want to use rubbing alcohol to help dissolve the lanolin (did I mention they are attracted to “dirty” wool? That includes the smell of lanolin.) After cleaning, card with clean “junk wool” to help dry it up. Try not to get the wood soaked. Don’t let your carder remain wet for long, because I’m not sure if that will cause the teeth to rust. Don’t let rubbing alcohol sit on the rubber backing, because it will cause the rubber to swell, and it will dissolve any glues used to hold it down. Do not use bleach on rubber, it will cause it to crack.
To be safe, check with the manufacturers of your tools for their recommendations on the best products and methods to keep them clean.
Deep cleaning work areas:
Vacuum the heck out of it. If you work on the couch, make sure you lift cushions, get in the cracks, etc. Have someone help you lift the couch and vacuum under there as well. Vacuum around desks, vents, in the vents if you can reach, blinds, etc. If you have a fiber studio, move the furniture and vacuum around it too, along any baseboards, under the rugs, etc. You may also use this time to spray the edges of the room down with an insecticide, if you desire, or grab some boric acid (you can pick it up at the dollar store) and sweep it into any cracks and crevices in the room, and behind furniture. I do not recommend using moth balls, and check toxicity of any pesticides you choose to use. The idea here isn’t to poison your stash - the chemicals are known to be toxic to humans and pets. When used effectively, you won’t want to handle that wool anyway (effectively is in an airtight container, not a few balls thrown on a shelf, and refreshed once a while - they smell so bad though, I’m not sure how they ever caught on). Regular vacuuming will likely get rid of them without you even knowing they were there, hence why some people think they probably haven’t deal with wool moths. They just sucked them up before they had a chance to do much damage.
After vacuuming, make sure you remove the vacuum bag or dump it out if it’s bagless - take it outside to do this so you don’t accidentally re-infest the area.
Here’s why cedar chests aren’t very effective, especially if it’s your great grandmother’s old chest that’s been handed down. Cedar needs to be fresh to work. Cedar-lined closets are beautiful but only work the first few months after they’re installed. Even then, they only work on tiny larvae, not larger ones or moths. It won’t stop an infestation. If you do have a cedar chest or closet, you’ll want to either sand it down every few months, or spray it down with cedar oil. Those little cedar blocks on hangers are a marketing ploy at best to get people to spend money unnecessarily on a false promise. Having cedar essential oil heated in a diffuser in the room honestly would probably be more effective as a preventative.
While we’re on the topic, lavender only repels moths at best, but it also won’t kill any already present, and it won’t stop an infestation. Yes, I have used lavender as a preventative - I’ll add a few drops of lavender essential oil when rinsing out wool after dyeing it, and I have sprayed items I needle felted with a lavender hydrosol before sending them off. I also recently purchased some cloth bins to help me contain my wool (so it’s not spilling off the shelves) so they’ll get the monthly lavender spray after vacuuming. All this does is keep them away for a short while. You do need to keep it fresh to maintain effectiveness.
If you work with raw fleece:
Wash/scour any dirty fleece coming in, or make sure you keep it bagged in thick bags, double if you need to, and away from your working fiber. These bugs love dirty fleece. I keep my to-be-scoured fleeces in the another room and away from my studio. This actually saved my arse, since one of them was infested. While scouring and dyeing the wool can take care of them (they can’t survive above 120 degrees fahrenheit) - as long as you don’t do the cold soak process. Though, to be honest, I’m not sure if they could survive the conditions of the ferment that’s involved in that process.
how to deal with moths when you find them
Forget freezing.
Freezing any wool (at home, with our home freezers), especially if only done once, will only put them into hibernation. It won’t kill them. Remember how I said they can take up to two years before they pupate? If this is how you dealt with them and then put your wool back in a bin, you’ll want to go back, take that wool out and check it again. And again. And again. Keeping wool outside all winter in an uninsulated barn just slows them down. Unless you live in the arctic tundra or are needle felting in Antarctica, your winter temps aren’t likely to get (or maintain throughout the week, day and night) negative 20F.
So your other options are chemicals, fumigating, or heat. I think, for most of us, chemicals are out of the question. We like to use our wool to make things like clothing, blankets, and toys - things that are meant to be handled and loved. As I stated above, the idea here isn’t to poison your stash.
Fumigating can be done by anyone. All you need is access to dry ice, which you can buy from many places, including Walmart (maybe call ahead and ask). It’s pretty cheap, at one to three bucks a pound. You will need thick contractor bags (3mil), 2-3 lbs of dry ice per 30 gallon bag, and any wool that needs to be treated. Make sure you wear gloves when handling dry ice! Wrap the dry ice in an old rag or t-shirt, place it in the bag, and add your wool (might as well treat your sweaters too while you’re at it). Tie the bag with a twist tie - you don’t want it to be airtight, the carbon dioxide needs to escape. Once the dry ice has completely evaporated, then you want to tie off the bag tightly and let it sit for four to five days. You can also store your clothes for the winter this way, just fumigate them ahead of time, tie them up in the bag, and store them in there.
Treating with heat is an extremely effective way to kill moths in all stages. It’s also probably the fastest. While moths can handle the cold, they can’t take the heat (har har). You need sustained temperatures above 120 degrees fahrenheit - which is the setting most people keep their water tank at (140 is factory standard I believe if it wasn’t adjusted). I like to go a bit hotter than the bare minimum, just to make sure they’re dead dead. This is why I recommend scouring any wool as soon as you get it, especially if it’s a bargain bag that had been sitting in a barn somewhere for a while. If you can’t get the water hot enough, adding a pot of boiling water to the scouring water will help (I have done this with an infested fleece). Any eggs and larvae that miraculously survived the scouring process are incredibly unlikely to survive the dyeing process, due to the acidity needed to set the dye and sustained hot temperatures needed to dye it.
I repeat: do not store unwashed, dirty fleece in the same space as your working area.
If you spotted some eggs and larvae in your already washed/dyed/carded stash, your next option is the oven. I believe the warming setting on most ovens is 150 degrees Fahrenheit, which is perfect for dealing with infested wool. Just grab some aluminum pans from the dollar store, place your wool in there, making sure that it’s not touching any burners or sides of the oven (you don’t want to singe your wool, and/or transfer any grease from cooking), and set it on the warm setting for 30 minutes. Afterwards, your wool is baked and safe. You can go through it again, picking out any larvae, vacuuming up any remaining eggs that drop out, and put it back in your stash. It’s probably not a bad idea to treat any incoming wool this way before adding it to your supply. As soon as you unpack it, stick it in the oven. The heat setting is lower than the temperature used to dye the wool, so it shouldn’t be an issue - but please keep an eye on this, set a timer, anything so you don’t leave it baking in there. You can also use this method to treat any already felted items, not just your stash. Again, I tend to go a bit hotter personally, because I want these suckers well done, so I tend to set mine at 150-180 and maybe around 45 minutes. You will probably want to do smaller batches if you have huge batts to make sure the heat penetrates into the middle of it.
To help you remember, here’s a simple graphic for you to pin, or save to your phone, or whatever so you can refer back to this post if needed.
Photo credit: Carolyn V on Unsplash
If you do all these things that I mentioned, even if you find some eggs or larvae in your supply, you’ll take care of any problems before they’re a problem. See? No worries!
Thumbnail and social sharing photo by krakenimages on Unsplash
