I found 5 of these things in my home recently. There were only 2 steps away from my yarn storage room. Never paid them much attention previously but somehow when I saw them crawling slowly towards my yarn room, all the little hairs on my neck went on alert. A frantic google search confirmed my fears. M-O-T-H.
The household casebearer, Phereoeca uterella, is a moth in the Tineidae family of Lepidoptera. Many species in this family are casebearers and a few are indoor pests of hairfibers, woolens, silks, felt and similar materials. Most people know this species by the name "plaster bagworm."
The larval case is a slender flat fusiform or spindle-shape case which resembles a cantaloupe or pumpkin seed. It can be found under spiderwebs, in bathrooms, bedrooms and garages. Cases can be found on wool rugs and wool carpets, hanging on curtains, or underneath under buildings, hanging from subflooring, joists, sills and foundations; on the exterior of buildings in shaded places, under farm sheds, under lawn furniture, on stored farm machinery and on tree trunks.
Regular cleaning practices, increased use of air conditioning in houses, and reduced number of woolen goods, along with pesticide application in cracks and crevices for household pest control, have decreased the incidence of the household casebearer. Manual picking or vacuuming of cases and spider web removal should be enough to keep this species under control.
And then I read this line and nearly fainted :
"....when woolen threads and woolen cloth were offered to the larvae “they ate eagerly”. "
I spent the next few days crawling on my hands and knees, and peering underneath sinks, scrutinising door frames, and combing all corners and cracks of doors, in an effort to find more of them. I did find more, and I also found 2 x dead mama moths, and lots of little old spider webs behind chests of drawers, behind the fridge etc.
Lest you think we're a dirty family who don't clean their house, we do have cleaners over every week, and they vacuum and wipe and mop. It baffles me as to where all these things come from, and how I'm supposed to regularly move the fridge & heavy furniture to vacuum away those old spider webs which the moth cases feed on!
At any rate, I ziplocked up all my yarn - praying that there were no eggs in the existing yarn stash... and put cedar blocks in my yarn storage cupboards. I did try to shake the yarn to see if I could identify any 'eggs' or moth-like tendencies, but not knowing what exactly to look out for, I hoped for the best.
This is my yarn storage area now... the stash still looks kinda naked and vulnerable, even clothed in their protective ziploc bags. Maybe I should revert to plastic bins - what do you think?