Did you know that the last stage in an insects life is the imago, plural imagines? While I wish I had imagined this, unfortunately I didn’t. A moth flew out of my closet a couple of days ago.
Though said insect is now smashed to smothereens, I am sure it was Tineola bisselliella, the dreaded clothes moth. Powdery, silvery green wings, erratic flight, yup, sure is the fiber artist’s nemesis.
As many of my sweaters were due for a wash, I went ahead and used my soaking and spinning machine* to work my way through all of my wool sweaters over the course of a few days. I thoroughly vacuumed the drawers in which I keep them and the closet itself.
The shawls gave me pause. All of that blocking to be redone was more than I could face. So I baked them.
Recalling that at work (where we handle tons of grains and flours) we occasionally heat the whole building up to quell meal moth infestation, I wondered if something like this would work for wool moths. After some research in agricultural texts and on-line information**, I concluded that if I got my knits over 140F for several minutes (or 160 F for less than a minute), I should be able to knock out any and all forms of moth – egg, larva, or adult. Combine this info with my favorite feature of my kitchen range, the warming drawer, and you’ve got a straightforward method for disinfesting delicates of these pests.
I set the warming drawer on High, wrapped the shawls in a light cotton towel, stuck a meat thermometer into the middle to make sure I get them up to 140F, and baked my shawls free of any insidious infestation.
Bonus – thanks to this unasked for prompt, I have gotten my annual sweater wash done earlier than ever before.
Note – do not do this with garments that you aren’t sure are clean. Heating causes all sorts of great chemical reactions between sugars and proteins (like the ones in that egg salad that dripped on your sweater the other day, or the sweat that has been accumulating on the edge of that cowl) and these reactions create delicious flavors and very brown stains. This is what is happening, by the way, when stains slowly appear on old clothing – the heat just speeds all that up.
*A.K.A. washing machine – great for soaking multiple sweaters at once and spinning the water out – just don’t ever let it agitate them!
** Tang, Juming; Mitcham, Elizabeth; Wang, Shaojin; Lurie, Susan. 2007. Heat Treatments for Postharvet Pest Control: Theory and Practice. CAB International, Oxon, UK.
**Cranshaw, W. 2003. Fact Sheet No. 5598, Indian Meal Moth. Colorado State University.
Image of clothes moth from Wikimedia Commons.