Tuesday, April 7, 2009

Ask FYV - Pests: Pill Bugs

A friend writes:

do you think Pill Bugs are bad for the garden. I have quite a few; found this snippet on internet and wondered if you agreed:

Pill bugs (or roly poly's as I have always called them) feed primarily on decaying matter. I have observed them in my garden for long periods of time, and done a little research, just to figure out what they are doing (I obviously have no life (but am afterall, a geeky scientist)). In my garden, they are certainly prolific, but appear to chow down on the remnants of my compost pile that hadn't completely broken down. These observations have put my mind at rest, and confirmed that these crustaceans are actually beneficial to the health of my garden. However, I might also point out that my small garden consists only of peppers, corn, cucumbers, tomatoes, and lettuce--that is to say, they may have an appetite for other plant varieties and thus could potentially wipe out a garden of other plant species (although I think this is rare and unlikely). Most crustaceans in this world (be them terrestrial or aquatic) are primarily scavengers--they are the "garbage men" of the microcosmic insect world. They eat fungus, molds, and other dead things and play a beneficial role in the cycle of nutrients. If you have vegetative plants that are dying, it is likely the cause of some other perpetrator--likely one that you cannot see with the bare eye. Roly-poly's in your garden, in my opinion, are a sign of a healthy nutrient exchange. Look in to other likely pests such as aphids, parasites, or even vegetative diseases.

So, I did a lot of research about this a few years back as I was having a terrible time with "something" eating lots of my seedlings in particular.  I turned to the gardenweb.com forums about pests and (this sounds ridiculous) there was a RAGING argument about pill bugs, with people in both camps either that they only chew up dead/dying leaves and others (including me) insisting that they were killing live plants, particularly seedlings.  Someone finally noticed that everyone that claimed pill bugs killed live plants lived in a southern state, particularly CA & Texas. It seems that in the warm climates, especially with heavily mulched beds, the populations become very large and voracious without a strong winter chill to knock back the population. I personally observed one night with a flashlight an entire 4'x4' planting of bean seedlings that were just beginning to germinate  get eviscerated.  Basically every seedling that was beginning to unfurl was covered in a few pill bugs each.  Also I had a  young, tender basil plant get stripped in a single night. They seem to also destroy my potato leaves. The best organic solutions are either submerged cups of beer (usually a slug remedy) which get filled with pill bugs on a nightly basis where they drown. Also large dustings of diatomaceous earth seem to work. I am pretty sure that this worked, though it is harder to tell. I am just now having a lot of problems again, so this is a good reminder to set things up again.

So there you have it, if you live in a part of the country with a real winter, don't worry too much.  If you live in a glorious part of the country with no freezing winter, watch out!

What I would really like is to put some chickens in the beds for a couple days to decimate the populations.

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