Why Caterpillars Infest Your House

The army worms or tent caterpillars of May 19 had dispersed in the morning but returned to my house at night, this time to the kitchen. They crept up walls and cabinets, through the red-pepper barrier beneath the door, and squashing them left and right I thought I'd go mad, using up paper towels and tissues, finally bringing out the vacuum, harassed, disgusted. Worse than ants. There is nothing in this house for caterpillars to eat, no plants, no breadcrumbs.

But there were none in the guest room although last night they were there by the hundreds; only in the kitchen. Their doors are only a few feet apart. Why were they choosing only the kitchen this evening? (Want to see them crawl? Video, 35 seconds.)

Answer: Light. The guest room was dark tonight but the kitchen was lit. Army worms are caterpillars, soon to become moths, and moths are attracted by light. It must be that caterpillars are, also.

I shut off the kitchen light. Their numbers diminished. I doused all lights in the house but one. Their numbers diminished.

Searching the Net (briefly, because in a minute I'm going to bed and turning out all the lights) I couldn't find this conclusion anywhere else but in a book published in 1896 by the Massachusetts State Board of Agriculture. But I'm telling you: Caterpillars invading your house at night? Shut off the lights!

Invasion of the Army Worms

The army worms or tent caterpillars hatched, millions of  'em. I figured they were a feast for birds, but they crawled like an army toward my house and then at lights-out in the guest room, about 2 a.m., I saw Pseudaletia unipuncta crawling all over my walls and carpeting. . . they kept advancing. . .I vacuumed up maybe 200 in all. Wondering where they found entry, I stepped outside, and the stoop and the door were PAVED with the crawly things (dropping thousands of black pinhead turds), and around my head buzzed a universe of wasps dive-bombing and eating them. Immediately I threw lime over the largest mass of worms, and then bleach, and then powdered my threshold with ground red pepper.

With a sigh I lay down in bed only to see one descending from the ceiling via a silken string. Grabbed it with a tissue. They spurt reddish-brown when crushed. (My kitchen floor looks like somebody cut an arm real good with a chef's knife.) The next morning I found a worm sharing my bed. (That's not a joke; that's literal truth.)

So shocked was I by the nighttime home invasion I didn't take many photos until this morning when I surveyed the battlefield with all the satisfaction of my ancestor Genghis Khan. Then I examined what these caterpillars had done to plants: skeletonized the leaves [see above photo], and they were still at it, so many thousands that their crunching and droppings are audible, like light rain.

When they find a suitable spot they begin growing white fuzz to cocoon themselves [photo at right], hoping to become moths in a little while. I have never ever seen an invasion of army worms like this. Their ranks also included true inchworms (thin green ones), and fat green caterpillars. I vow to fight them to my last pepper flake.