What are Pill Bugs or Roly-Poly?
Any time you look under a rock, board, log, leaf litter or a flower pot in your garden, you will probably find a bunch of little gray “bugs” that look a bit like tiny armadillos.
If they are the common pillbug (Armadillidium vulgare), when you touch them they may roll themselves up into a tight ball, just like armadillos.
There is also a variation known as the sow bug (Porcellio laeyis), which are very similar but do not roll up in a ball.
What are these creatures? Are they damaging to your garden? What should you do (if anything)? In this article, we explore these questions. Read on to learn more.
Are These Bugs Insects?
Pill bugs earned the common name “roly-poly” bugs because of their ability to roll up. Sow bugs are so-called because of a vague resemblance to pigs. The fact is, neither are actually bugs or insects.
Instead, they are isopods (crustaceans) and are thought to have originated in an aquatic setting. These little animals are actually distant relatives of shrimp, crabs, and lobsters.
Roly Poly – Not Insects Look At Their Legs
- PIll bugs have seven sets of legs on their body, insects have three pairs.
- Sow bugs and pill bugs are absolutely harmless to people.
- They don’t carry diseases, and they don’t sting or bite.
In the garden, these members of the Armadillidiidae family from the order Isopoda, is terrestrial crustacean group which typically coexist happily with other flora and fauna, eating decaying plant material, leaves, wood and other organic matter.
In very rare circumstances, they eat young plant roots, shoots and leaves.
Where Do Roly-Poly “Bugs” Live?
These critters have a wide distribution and about a dozen varieties of them can be found all over the United States and North America.
I remember collecting them as a kid growing up in Florida.
In areas where the weather gets very cold in the winter, they hunker down under logs, plant matter, leaf litter, and other protection and wait it out.
Because these little garden dwellers are crustaceans and actually breathe through gills, they must live in moist areas with humid conditions.
You don’t need to look far to find roly-poly’s in your garden.
Just turn over a spadeful of flower-bed mulch with moist soil or overturn a log or rock in a damp area, during the day and you’re sure to find a large population of them.
At night, when it’s dark and cool, you may find them ambling about.
Pill bugs prefer a cooler climate. If it is very hot and dry, they find deep cracks, crevices, and crawl spaces or dark, damp spaces with high moisture under rocks and logs to hide until the drought is over.
If it goes on too long, they will all die because they need moisture to be able to breathe.
Furthermore, the female carries the eggs and the young rather than depositing them means the eggs or young will perish if the female perishes.
What Is The Pill Bug Life Cycle?
The critters breed early in the spring, but unlike their cousins (shrimp and lobsters) they do not lay their eggs in water.
Female pill bugs and sow bugs carry their eggs in a damp, leaf-like abdominal brood pouch until they are ready to hatch. This takes about a month.
Once the eggs hatch, the babies stay in the pouch for a couple of months.
When ready, the young begin seeking out food on their own. Baby pill bugs and sow bugs are miniatures of their parents. They molt 12 times before attaining their full size.
They mature and are ready to reproduce at about one year old.
They are able to produce three broods (25-200) of offspring annually. A pill bug can live for about three years.
What Do Pill Bugs Eat?
This creepy crawlies eat mostly debris, so they are quite good for gardens and natural settings.
They are omnivorous and eat leaf litter, grass clippings, dead plants, dead insects, dead animals, fallen fruit and other organic matter.
They also eat stink bug eggs off the leaves of plants. This is a very helpful trait!
They very rarely eat young plants’ roots, stems and leaves.
When sow bugs and roly poly bugs eat organic matter, it passes through their digestive systems and is excreted.
This process increases the rate of decomposition in compost piles helps reduce organic litter and debris in natural settings. It also helps enrich the soil.
These creatures are very important at toxic sites, such as slag heaps and coal spoils because they are able to ingest heavy metals like cadmium, lead, zinc and copper.
Once they have taken these pollutants in, they become crystallized as spherical deposits in the midgut of the bug.
This process works to remove toxic metal ions from soil.
Because sow bugs and pill bugs are so tolerant of these contaminants, large numbers are able to thrive in ravaged settings.
Their presence helps stabilize soil so vegetation can become reestablished and help these contaminated settings recover.
The quick growth of vegetation over toxic sites helps to reduce metal ions leached into groundwater.
The presence of vegetation also assists in settling the toxic dust.
Can Pillbugs Be A Problem?
In a balanced, established setting, pill bugs will just hide during the day and amble about at night eating organic matter without bothering anyone.
In fact, they are a very important part of a healthy garden ecosystem and are generally valuable helpers in cleaning up garden waste.
In an unbalanced garden environment, pill bugs could be a problem.
For example, if you use chemicals and pesticides that kill off natural pill bug predators, you are likely to have a roly-poly population explosion.
If you clean up all the organic matter around your yard and don’t leave anything for the pill bugs to eat, they are likely to go for your tender plants, seedlings, and flowers.
If you have just acquired an unbalanced garden setting, you may have some pill bug problems for a while.
How To Deal With Unwanted Pill Bugs?
The wisest way to deal with any imbalance in your garden is to strive to establish balance.
For example, adding natural predators to your garden tends to keep populations of other garden dwellers under control.
Natural predators that help reduce pill bug numbers include:
- Predatory nematodes
Roly poly bugs may also eat one another occasionally.
If you are lacking a good natural balance in your garden, or in an unbalanced setting (such as a greenhouse) sow bugs and pill bugs may nibble on roots and stems and leaves that are touching the soil.
When this happens, follow the advice in the video above. You may also find that a little diatomaceous earth scattered around the affected plants will work to deter them.
What If You Have A Large Population Of Pill Bugs Or An Invasion?
Problem pill bugs are unlikely, but in very extreme situations, you may wish to try some of these solutions.
Sprays made with essential oils are effective against a number of different types of undesirable garden dwellers. Some of the most frequently used essential oils include:
- Tea tree
Other natural insecticidal sprays can be made using ingredients such as:
- Garlic oil
- Chili pepper oil
- Cayenne pepper sauce
Mix these substances (alone) with water at a rate of one tablespoonful per quart of water.
Be careful with the peppery ingredients, they can irritate skin, eyes and nasal passages.
Trap Or Bait Pill Bugs, Sow Bugs, Slugs & Snails
Make pill bug traps by putting whiskey, apple cider vinegar, apple cider or beer in shallow dishes around the garden at dusk.
You will also catch slugs and snails with this method.
There are also commercially available insecticidal baits designed specifically to kill pill bugs.
Most of these pest control products are made using iron phosphate, spinosad spray, metaldehyde and/or carbaryl.
These ingredients are also effective against slugs and snails.
How To Keep Pill Bugs Out Of The Garden?
If you don’t want any pill bugs around, you can remove all debris and dry up any damp areas.
However, doing this will limit the types of plants you can grow.
If xeriscaping is your goal, this might be a good idea.
However, because pill bugs are so ubiquitous, don’t count on keeping a dry garden to keep them away.
You’ll probably still find roly-polies hiding out at the base of your cactus and under stones in the rock garden.
Mulching between rows in your veggie garden with black plastic sheeting may deter them because they will not like the heat beneath the plastic.
However, this technique may have the opposite effect because it may drive pill bugs to seek refuge around the damp, tender stems of your plants.
Taking care to water early in the day so the soil is dry by evening may also discourage them.
But, it may create the opposite effect in that they will seek out moisture where they can find it.
That’s likely to be closer to your plants.
All-in-all, keeping pill bugs out of your garden is really not necessary and not a good idea.
It’s far wiser to take care to establish a good, natural balance.
Mulching with organic matter and providing an inviting habitat for all manner of garden fauna ultimately results in a thriving, healthy garden.