Tuesday, March 25, 2008

The Pill "Bug" Debate

I’ve only—bless my lucky stars—found one garden snail in three years. I plucked it yesterday off the base of a sculpture in my garden that was awash with eight-inch tall, moist miner’s lettuce. Where was he hiding all the past years? Where are the rest of them? I bet he can’t be a bachelor. (This is the snail that escaped from an “escargot farm” after being introduced to California in the 1800s—not the rarely-seen native snail.)

But the sow bugs and pill bugs are now out in full force this spring.

Consider the lowly sow bug (they don’t curl up and have two tiny tails) or the cute pill bug pictured above, also called rollie-pollies—actually Isopods, the only land crustacean related to the lofty crab and lobster. These innocent little critters are beginning, once again with the advent of spring, to be falsely accused in the gardeners’ court-of-law. All kinds of people ask me how to kill, with safe methods, these "nasty bugs who are devouring everything in my garden”. I have to gently tell them that these particular critters may have been falsely incriminated by circumstantial evidence. If Perry Mason were still alive to represent these small, helpless creature in a gardener's court of law, they may be exonerated.

Although one gardener friend saw a pill bug eat a flower bud of a pansy. And a friend says, in greenhouses and young seedlings in flats where it can be very moist, pill bugs may be so abundant that they damage young plants. I asked Richard Merrill (my organic gardening “guru” with over 25 years of teaching organic gardening) about this and he responded “isopods prefer decaying organic matter... or rather more accurately they prefer the microbes of decay on the organic material. If they are without water and exposed to new seedlings, isopods will eat them also, but this is rather rare.”

So maybe it’s not beyond a shadow of a doubt.

Some commercial chemical compounds used by the uninformed to “eradicate” pill and sow bugs contain diazinon, a very toxic poison that is rated as equally toxic as the infamous DDT, And, according to the Rachael Carson Trust, is a suspected teratogen (causing birth defects in the next generation).

Pill bugs are part of nature's important decomposing cycle. That is, these “bugs” are usually eating mostly on moist rotten, decayed, dead, and decomposing plant tissues. Some other creatures, such as the nasty Mr. Slug, Mr. Snail, or Mr. Earwig, do the initial damage to the plant and the unsuspecting and opportunistic pill bug comes in to take advantage of the very first bits of rot, is falsely accused—and thus, is innocently killed.

Take strawberries as a wonderful example. As gardeners, we might awaken in the morning to find a pill bug neatly rolled up within a cavity so neatly carved within the largest, most gorgeous strawberry in the garden. If we were to actually reconstruct the "crime", what probably occurred was that herd of tiny slugs mounted a midnight raid of the berry patch, chewing tiny caverns in each berry. The very first tiny bits of oxidized-rot and decay sent (actually, scent) out a signal to the pill bugs that a new taste-treat of succulent decay was available. The pill bugs climb into these "condominiums" of repast and proceed to feast away. The sun slowly rises as the slimy villains, the slinky slugs, slither back into dark, dank hiding places, places that are not where they just got done feasting. The pill bugs, with carefree abandon, colonize the holes formally carved by other pests. The gardener finds the pill bug at the scene of the crime and inflicts a form of instant, shameless justice. Again Richard Merrill, “I have tried in vain to see isopods eat strawberries. I have seen slugs eat them (nocturnally) and then when the isopods become active, they seek out the holes in the berries for water.”

The "solution" I try to take, is not to try to eradicate sow and pill bugs. But I’m fortunate that I can mulch my perennials with turkey manure mixed with rice hulls and still allude these troublesome critters.

To reduce the populations of pill and sow bugs around her raised boxes of vegetables (as well a slugs, earwigs, and “escargot”) a friend maintains bare soil with no mulch and very little organic matter or fiber on its surface for four feet or more in all directions.

Plant only the most healthy and vigorous transplants (the pill bugs eat on the very first tiny bits of rotten tissue when a seedling has minute amounts of damage from mildew, rust, and damping-off) into warm, dry, and bare garden soil. Then flood flats and pots in a bucket of water to flush out pill bugs.

I think because my ornamental garden is never irrigated in the summer; I don’t have many slugs, snails (except the "Lone Ranger"), or earwigs. Lucky me!

But there are the pill bugs eating mulch and the decaying weeds I’ve pulled up.

Please comment – I’d like to know what you think.

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cyndi said...

I am a long time gardener in south east michigan. have a very small garden space behind my townhouse. my garden consists of cedar and cypress raised beds where I grow veggies. this year the "rollie pollies" have taken a liking to many of my plants, but especially my green been seedlings and cole crops. Seems every time I turn around, the beans are gone - or turned to lace. I've tried sprinkling diatomaceous earth, to no avail. these guys just seem to have a voracious appetite. I finally decided I'd grow some bean plants inside to the point at which the rollie pollies won't want to contend with them. then I'll place them in the garden. Never had this problem in many many years of gardening! any other ideas???

Anonymous said...

I could be wrong but the labeled picture above resembles the Pill Millipede, which is Glomeris marginata. Close resemblance, but different species.

marhawkman said...

No I looks like a pill bug to me.

One note on Teratogens: the birth defects are not always observed in the arthropods. They are also observed in humans. Thus these chemicals should be considered unsafe at any dosage. This of course means that using them for pest control is "unwise" at best and reckless endangerment at worst.

As for Pill bugs, I like 'em. I have seen them actually eat part of a seedling, but they didn't have anything else to eat at the time. Poor things got confused and wandered into a place where I was sprouting beans. Nothing but dirt and beans there. I have on other occasions observed them doing far more helpful things. On one occasion I observed a swarm of them attempting to devour an entire tree stump. Or maybe they were just eating the parts that had already rotted.


Anonymous said...

you shouldn't take these icopods forgrated. to me these are the cutest bug alive.i sometimes go out in my yard ,looking for 1

Anonymous said...

I have trouble with these bugs every year, growing pole beans. While the beans are sprouting, the pill bugs gang up on the new sprouts and devour.

I guess once one of them has made a nick in it or something, the tissues begin to deteriorate or whatever, and it becomes palatable, but they are definitely eating it.

Contrary to what is written in various places (I got here via a Google search), they tend to do it more when conditions are moist. To get the seeds to sprout, I generally keep the soil moist and that may be my mistake. Trying to keep a balance... Maybe they start when the shell of the bean seed has split off and itself is beginning to decay, but from there they go to the live tissue and eat up. Especially at the base of the new sprout!

I grew up loving pillbugs, and I know them well. In our community garden we cannot use pressure treated wood around our raised beds, and of course after a year or two the wood starts to decay. So the pillbugs have plenty to eat all year. They are there in big numbers. Most of the year they don't bother the living plants.

They already have plenty to eat, the soil is moist, and yet they DO eat the bean sprouts! As far as I can tell, it's for variety in their diet, and the sprouting beans are "just what they're looking for."

I did the web-search because I wanted to find a solution (and I'm not having much luck). It's frustrating to see so many "experts" saying it's not a problem!

Anonymous said...

i've got an infestation. i first noticed after moving into my new home that they devour my dog's feces in days. never thought i would have a problem in my front flower bed. i planted many pansies and at first i suspected a cat or night animal was chomping them because they were eaten so quickly and destructively. i found out cats don't eat flowers and there was no evidence of any other animal. last night i took a flashlight to inspect and to my surprise, there were multiple pill bugs on every pansy planted...what was left of it anyway. not sure of the best way to fight this infestation.

Robert Kourik said...

This is from an expert organic gardener friend: "To make sure we're talking about the same critters, your "pill bugs" look like tiny armadillos, with segmented "armor"? I want to make sure of the ID, as it is uncommon for pill bugs to eat live leaves - they usually eat decaying material and do so at night. But when there is a lot of dead plant material around there can be huge populations of these guys, and if hungry enough they could go for green leaves too.
First line of defense would be to clear away their hiding places as much as possible, including mulch, old leaves, etc. As organic gardeners we want to use these organic materials, but sometimes in spring we need to have clean soil surface near young plants long enough for them to get established.
If this does not do the trick, I think that the new formulation of Sluggo - Sluggo Plus - may "work" on pill bugs too; it does for earwigs.
I hope this helps at least somewhat."

Anonymous said...

Finally! someone who doesnt kill all animal life in their garden! too many people destroy "pests" without even considering the possibility that the solution could involve a cchange in THEIR practices.I have too often heard peole wondering what good pillbugs are, and I always feeel like saying "They LIVE! What's wrong with living!? Pillbugs are usually harmless, but if they are eating live plants, you could try watering your garden in the morning only, or not usng as heavy a mulch. Pillbugs are not evil!!!