# When caterpillar poop fell like rain (or, Whither the Gypsy Moth?) **URL:** \ **Category:** Factual Questions\ **Created:** [August 13, 2006, 9:05pm UTC](https://boards.straightdope.com/t/when-caterpillar-poop-fell-like-rain-or-whither-the-gypsy-moth/368586 "2006-08-13T21:05:33Z")\ **Posts on this page:** 13\ **Page:** 1
**Author:** ![jayjay](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jayjay/32/6765_2.png) [@jayjay](https://boards.straightdope.com/u/jayjay)\ **Post date:** [August 13, 2006, 9:05pm UTC](https://boards.straightdope.com/t/when-caterpillar-poop-fell-like-rain-or-whither-the-gypsy-moth/368586/1 "2006-08-13T21:05:33Z")
_The state of Pennsylvania is so wide, mein herr. Not only up and down but side to side, mein herr. I couldn’t even cross it if I tried, mein herr. But I eat what I find inch by inch step by step mile by mile pine by pine…_ In the mid-80s, Pennsylvania was undergoing our turn at the crisis known as the Great Northeastern Gypsy Moth Invasion. For about three years we stepped on caterpillars, got stung by caterpillars, got pooped on by caterpillars, while the Appalachians went as bald as Patrick Stewart. I’m sure there’s not a Pennsylvanian who was alive in 1986 who doesn’t remember having to move picnic tables out from under trees in order to have a barbecue that wasn’t seasoned with processed maple bits. I remember stepping on them, scraping eggs off of trees and posts, killing individual breeding moths, and watching the airplanes dust. And then it just stopped. Did the spraying stop them? Or did they just move further down the Alleghenies, as they’d moved in from New England and New York? Are there states that are still dealing with them? What happened to the gypsy moths? ---
**Author:** ![jnglmassiv](https://avatars.discourse-cdn.com/v4/letter/j/f07891/32.png) [@jnglmassiv](https://boards.straightdope.com/u/jnglmassiv)\ **Post date:** [August 13, 2006, 10:06pm UTC](https://boards.straightdope.com/t/when-caterpillar-poop-fell-like-rain-or-whither-the-gypsy-moth/368586/2 "2006-08-13T22:06:35Z")
Was it anything like this?: [http://ebaumsworld.com/caterpillar-infestation.html](http://ebaumsworld.com/caterpillar-infestation.html) ---
**Author:** ![Bill\_Door](https://avatars.discourse-cdn.com/v4/letter/b/50afbb/32.png) [@Bill\_Door](https://boards.straightdope.com/u/Bill_Door)\ **Post date:** [August 13, 2006, 10:23pm UTC](https://boards.straightdope.com/t/when-caterpillar-poop-fell-like-rain-or-whither-the-gypsy-moth/368586/3 "2006-08-13T22:23:01Z")
I can remember camping in the Adirondacks that summer and being kept awake by the sound of caterpillars chewing and the rain of litter. Gypsy moths seem to have a cyclic population growth, possibly an evolutionary tool to keep predator populations down. ---
**Author:** ![Athena](https://avatars.discourse-cdn.com/v4/letter/a/35a633/32.png) [@Athena](https://boards.straightdope.com/u/Athena)\ **Post date:** [August 14, 2006, 3:02am UTC](https://boards.straightdope.com/t/when-caterpillar-poop-fell-like-rain-or-whither-the-gypsy-moth/368586/4 "2006-08-14T03:02:56Z")
They were in Michigan this year, happily munching on my trees. Disgusting things. I can’t imagine 3 years of them. ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [August 14, 2006, 8:41am UTC](https://boards.straightdope.com/t/when-caterpillar-poop-fell-like-rain-or-whither-the-gypsy-moth/368586/5 "2006-08-14T08:41:38Z")
In most cases, natural plagues like that balance themselves out one way or another - usually either by producing abundant resources to boost predator/parasite/pathogen population, or by depleting food resources (it’s the old _foxes and rabbits_ thing). We had a ‘plague’ of ladybirds(USA: lady_bugs_) here in the UK in 1976; in some places they formed a thick layer on the ground, causing cars to skid and crash. The phenomenon just burned itself out due to lack of food(aphids). Of course, with organisms that eat a wide variety of different plant matter (say, locusts), in areas where humans repeatedly attempt to densely replant cultivated crops, then the above doesn’t always apply. ---
**Author:** ![jjimm](https://avatars.discourse-cdn.com/v4/letter/j/ba8739/32.png) [@jjimm](https://boards.straightdope.com/u/jjimm)\ **Post date:** [August 14, 2006, 9:07am UTC](https://boards.straightdope.com/t/when-caterpillar-poop-fell-like-rain-or-whither-the-gypsy-moth/368586/6 "2006-08-14T09:07:42Z")
> [@Mangetout](#): > > We had a ‘plague’ of ladybirds(USA: lady_bugs_) here in the UK in 1976; in some places they formed a thick layer on the ground, causing cars to skid and crash. The phenomenon just burned itself out due to lack of food(aphids). I remember that vividly! I had gone out sailing in Chichester Harbour with my grandfather. The water was bright red with them as far as the eye could see - and it wasn’t just one layer, it was ladybirds all the way down for a few centimetres. The ones that didn’t drown were biting. Apparently they came over the channel from France. ---
**Author:** ![Jonathan\_Chance](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jonathan_chance/32/701_2.png) [@Jonathan\_Chance](https://boards.straightdope.com/u/Jonathan_Chance)\ **Post date:** [August 14, 2006, 11:31am UTC](https://boards.straightdope.com/t/when-caterpillar-poop-fell-like-rain-or-whither-the-gypsy-moth/368586/7 "2006-08-14T11:31:32Z")
I seem to recall there’s been a growth of some fungus that’s culled them back recently. But boy were they a pest prior to that. ---
**Author:** ![Carlyjay](https://avatars.discourse-cdn.com/v4/letter/c/e0b2c6/32.png) [@Carlyjay](https://boards.straightdope.com/u/Carlyjay)\ **Post date:** [August 14, 2006, 1:11pm UTC](https://boards.straightdope.com/t/when-caterpillar-poop-fell-like-rain-or-whither-the-gypsy-moth/368586/8 "2006-08-14T13:11:11Z")
We went through the exact same thing in Ontario. And yes, it was just like the ebaumsworld photos. My family had a pool in those days, and it was really, really, REALLY gross to step on those things on the concrete in your bare feet. But it was unavoidable. _shudder_ I don’t know why the plague stopped, but thank goodness it did. ---
**Author:** ![CalMeacham](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/calmeacham/32/35_2.png) [@CalMeacham](https://boards.straightdope.com/u/CalMeacham)\ **Post date:** [August 14, 2006, 1:16pm UTC](https://boards.straightdope.com/t/when-caterpillar-poop-fell-like-rain-or-whither-the-gypsy-moth/368586/9 "2006-08-14T13:16:25Z")
They were already pretty bad when I lived in Binghamton, N.Y. in 1982. The trees hadn’t been devastated, but you could hear the fall of “frass” (that, I learned, is the correct word for “caterpillar poop”) as if it was rain, even on a clear day. ---
**Author:** ![gigi](https://avatars.discourse-cdn.com/v4/letter/g/a587f6/32.png) [@gigi](https://boards.straightdope.com/u/gigi)\ **Post date:** [August 14, 2006, 2:14pm UTC](https://boards.straightdope.com/t/when-caterpillar-poop-fell-like-rain-or-whither-the-gypsy-moth/368586/10 "2006-08-14T14:14:20Z")
> [@CalMeacham](#): > > They were already pretty bad when I lived in Binghamton, N.Y. in 1982. The trees hadn’t been devastated, but you could hear the fall of “frass” (that, I learned, is the correct word for “caterpillar poop”) as if it was rain, even on a clear day. Yep, I was in my hometown Kingston for the infestation. People put sticky bands around the trees to catch them when they descended at night (during the day? not remembering the details) ---
**Author:** ![username\_taken](https://avatars.discourse-cdn.com/v4/letter/u/c0e974/32.png) [@username\_taken](https://boards.straightdope.com/u/username_taken)\ **Post date:** [August 14, 2006, 2:55pm UTC](https://boards.straightdope.com/t/when-caterpillar-poop-fell-like-rain-or-whither-the-gypsy-moth/368586/11 "2006-08-14T14:55:56Z")
I grew up (and still live) in NH. I seem to remember the infestation as being around '82 or so (I was 6). I can remember walking barefoot down the road and trying not to step on any, yet always ending up stepping on a few (eww- wet and hairy!). I also remember my bike tires becoming slick from running them over. And those sticky bands people put around trees that **gigi** mentioned were a common sight. I remember that the bands would still be visible years later as a strange stain on the tree trunks. On to the OP: I thought they were cyclical in their infestations. I remember hearing back then that they’d return in 20 years. In fact, I was riding throught the mountains yesterday and noticed the trees along route 93 up in Plymouth, NH being covered with Gypsy Moth tents, kinda like how I remember the trees when I was a kid. So, will they come back? ---
**Author:** ![gigi](https://avatars.discourse-cdn.com/v4/letter/g/a587f6/32.png) [@gigi](https://boards.straightdope.com/u/gigi)\ **Post date:** [August 14, 2006, 3:24pm UTC](https://boards.straightdope.com/t/when-caterpillar-poop-fell-like-rain-or-whither-the-gypsy-moth/368586/12 "2006-08-14T15:24:48Z")
I had heard back then that 17 years was the cycle. But I could swear I’ve seen a few caterpillars on the ground here (southwest NH). ---
**Author:** ![D\_Odds](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/d_odds/32/2882_2.png) [@D\_Odds](https://boards.straightdope.com/u/D_Odds)\ **Post date:** [August 14, 2006, 3:36pm UTC](https://boards.straightdope.com/t/when-caterpillar-poop-fell-like-rain-or-whither-the-gypsy-moth/368586/13 "2006-08-14T15:36:57Z")
17 years is the [cicada](http://insects.ummz.lsa.umich.edu/fauna/michigan_cicadas/Periodical/Index.html). > [@](#): > > Periodical cicadas are found in eastern North America and belong to the genus Magicicada. There are seven species – four with 13-year life cycles (including one new species described in 2000), and three with 17-year cycles.