Saturday, May 10, 2014

The Dreaded Moth



I thought it was time to tell you all about the fibre artist’s worst nightmare; the clothes moth.   Clothes moth is a not entirely accurate name; this moth isn’t interested in all clothes, just those made from protein fibres.    Your cotton, linen and other cellulose fibres are fairly safe, as are the man-made fibres.
The moth I normally come across is the Case Making Clothes Moth, so called as it makes a little case for itself before it becomes a moth; this is what you’ll normally find in your stash, along with dead adults and frass (or moth poo).    Now before you start worrying about every moth you see, keep in mind these guys are usually not seen.   They hate the light, so the ones fluttering around your porch light are safe.  If you ever see an adult clothes moth it’ll be fluttering or scurrying away from the light as fast as it possibly can.    They’re small too, only about 6 to 8mm in length and a light buff colour.  They’re often a little tatty looking too.  The actual damage isn’t done by the moth, it’s the larvae which eats the stash, they’re also the ones that make all that peppery looking poo (frass is the correct term) that you find in the bottom of the box or bag.
This is what you'll see; all those little peppery spots are frass and the tube is a case for the moth.  There were dead moths elsewhere in the bag as well.  This was all in a zip-loc bag and they did eat their way out.

The first step with these guys is to not get them in your stash in the first place.    They like fibres that are contaminated with food over clean fibre and from what I’ve seen they love raw alpaca and absolutely adore raw possum!    I’ve found them in sheep and goats fleece as well though, so they’re not that picky.  If possible wash fleeces to reduce the odour that attracts them, store with strong smelling things like cedar (best option) or lavender or even soap will help.  Make sure these things don’t have direct contact with the stash, put them in a cloth bag so their oils don’t contaminate your stash.    Now these things won’t kill the moth, but they will make it harder for it to find your stash.  Also store in plastic bins, clear is best as it lets in the light which will discourage them.  Zip loc bags can be helpful, but moths can chew through them to get to something that smells nicer to them.
In addition to the above, go through your stash at least once a year.   The moth doesn’t like being disturbed, and if it is in there you’ll likely find it before the damage gets too great.
If the worst should happen (as it has to me on a few occasions), don’t panic, swearing doesn’t really help I’m afraid, keep calm and start to sort out the problem.   Often the moth will come into your stash from something you buy, at the time you buy it there won’t be any sign you can see.   You could quarantine it, but would need to do this for quite some time and we don’t all have the room or time for this; not to mention most purchases are fine and not carrying any nasties.
The first thing to do is to take out the box that’s got the infestation (or bag), take it outside and start going through it.   I also check boxes within a few feet of the original to be certain that they’re ok as well.    The source of the infestation is normally binned straight away; it’s usually obvious which one that is as there will be dead moths, casings and lots of frass in there.   Don’t try to save it, it’s not worth it.    Check for signs in the rest of that box, if everything looks ok then it’s time to treat it to make sure it’s ok and stays that way.
Empty the box and give it a good vacuum, if you wish you could also wash it in hot soapy water.    If the fibre is a greasy fleece now’s the time to wash it in water that’s at least 50 degrees and you want to keep it at that temperature for 30 minutes at minimum.   If the fibre is natural that you’re intending to dye, get to it as the temperatures in dyeing will kill all stages of the pest.
If you can’t wash it or if it’s already dyed you have two options.
1.       This was the option I normally used until recently.   You need a deep freeze, a proper chest freezer, not the one attached to your fridge.   Freeze everything for at least four days; I normally go for a week.   Take it out and keep it in the warm for another four days.   Put it back in the freezer for a week and repeat.   I would do the freeze and warm cycle three times.   The cold kills the larvae and the adults, but not the eggs; the warmth persuades them to hatch and then the freezer kills them.    I’ve not had any problems with anything I’ve used this method with.
2.       This is the option I tried with the current infestation.   No signs of moth anywhere except in one bag, but the bag had been eaten through and some frass had got out so I wasn’t leaving anything to chance.   My freezer was full, so I did a little research and found that heat also kills them and it kills all parts of the lifecycle.   50 deg centigrade for 30 minutes minimum is what you need and I figure that since all my dyed fibre has hit that temperature in being dyed it’ll survive perfectly well if I did it again.   So, I used my largest roasting dish on the bottom shelf of the oven and heated it at 50 for 40 minutes.   The fibre came out of the oven without any damage (this was all Merino or Merino/Silk); I had a couple that I stuck in the freezer still but they included bamboo as part of the blend and I wasn’t sure how that would be in heat.

After treating your stash then put it back in the cleaned container and keep a close eye on it for a while.   I also contact the place I got the infestation from to let them know; most people appreciate knowing and it reduces the chances of it happening again.

I hope those of you who do get this in your stash can use this to help; I really hope no-one needs it, but unfortunately I know some will.

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