Infestation

We have an infestation of casebearer moths in our house.  What are casebearer moths, you might ask?  Well, for those of you who have followed the blog since the beginning you may remember the post Slugs, Bugs, and then Culture Shock.  For those of you who don’t remember, let me refresh your memory.  Back in October, I wrote the following:

In addition to a slug and the ants, there are these mysterious flat, almond-shaped “things” hanging on the walls and ceiling of our house.  I noticed them the day we moved in.  I thought they were just some weird, dried up, dead bug, but last night as we ate dinner, I saw one on the wall and – jeepers-creepers – it was MOVING around. I picked it up with my tweezers (after eating of course) and it turns out that they have this disgusting black tentacle thingy that pokes out that helps them mobilize… (No legs were visible!) It’s one thing to have a weird, unknown dead creature on your wall, and quite another thing to see it move around and have no idea what the heck it is.  I still have the heeby-jeebies and am on a mission to rid the house of all of them, dead or alive.

Being that I am intensely curious, I not only went on a mission to rid our house of these, but also on a mission to find out what the heck they were.  I became especially obsessed with this quest more recently when I would wake up in the middle of the night, turn on the light, and find dozens of them crawling around on my wood floor.  I was NOT okay sharing my bedroom with these creepies.

I searched on Google numerous times, having no idea even what words to choose to describe the cocoon-like creature found in every crevice.  “Weird worm in cocoon + Costa Rica.”  Or “almond-shaped cocoon” or “moth species Costa Rica”. (I knew what I was seeing was the larva form of a moth-to-be because there are always tons of little moths flying around our house, but I wanted to know MORE).  Nothing was giving me the information I was seeking, but after hours of crappily-worded searches, somehow or another I finally stumbled on a couple pages that shed some light on this mysterious intruder. 

They are called “Bagworms” or “Casebearer Moths”. This is what they look like up close:

My curiosity was finally satisfied.  I don’t know why I didn’t think of the word combination “case” + “moth” before.  My brain was stuck on “cocoon”.

Basically, what we’re seeing, and yes, what our house is infested with, is actually a caterpillar inside a protective case.  It drags the case around as it’s in its larva stage.  Eventually, it goes through the ‘pupa’ stage inside the case, creating a cocoon of sorts inside.  Crawling up a wall, it attaches itself, and according to this website, emerges as a tiny moth the next day around noon.

Below are a few excerpts from the website.  I highlighted the phrases that I found particularly interesting.  Or disturbing.  Anyway, for those of you who are curious like me, you may continue reading… and viewing my gross pictures.

Excerpts taken from:

http://entnemdept.ufl.edu/creatures/urban/occas/household_casebearer.htm

 

Description

Egg: After mating, females lay their eggs on crevices and the junction of walls and floors, cementing them on debris. Two hundred eggs may be oviposited by a single female over a period of a week, after which she dies. Eggs are soft, pale bluish, and about 0.4 mm in diameter. 

Look close and you will see a case sticking out from under the top molding.  I scraped this out with a nail. 

A partial-view of all our wood 'crevices'.  In every 'crevice' or gap between pieces of wood are several old or new casebearer moth cases.

Larva: The larva is not usually seen by most people. The case that it carries around wherever it feeds is what is immediately recognized. 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. 

This is underneath a shelf in Kate's closet.  The picture doesn't do justice to how many were actually hanging there.  Probably about 50.

Management

Due to its food habits the household casebearer is a potential household pest. However, regular cleaning practices, increased use of air conditioning in houses, and reduced number of woolen goods in this part of the country, 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. [I am obsessed with 'manually picking' these critters out of the 'cracks and crevices' of our house.  My favorite tools to do so: a tiny screw driver and a nail.]

A pile of old cases I cleared out from just one wall yesterday.  I know... I'm weird.  But like it says, manual picking helps to keep the population down!

 So, all this to say, at least I know what they are now.  And if read all the way to the end, you probably are in agreement with me: these things are GROSS!