Are Pill Bugs (Rollie Pollies) Good or Bad For Gardens?
Gardening always comes with challenges. Some of these challenges include various pests, bugs, or other garden nuisances. One of these pests, is the pill bug, also known as the rollie pollie. These little bugs are usually targets of small children to play with in the dirt outdoors. But what happens when you see them in the garden? Are pill bugs good or bad for gardening? In this article, organic gardening expert Logan Hailey answers this question.
Remember playing with those little rollie pollie bugs when you were a kid? When you touch them, they roll into little balls.
Doodle bugs are also tasty treats for birds, frogs and some kids feed them to their pet lizards. You may even remember Grandma complaining about the little armadillo-looking bugs eating her garden plants.
Whether you call them rollie pollies, doodle bugs, or pill bugs, these garden creatures are found throughout the U.S. and beyond. Pill bugs are usually not an issue, but many new gardeners wonder “are they bad for my garden?”
Garden Friend or Foe?
Like most things in nature, the answer is not a clear “yes” or “no.”
Rollie pollies can be beneficial, harmless, or they can cause a lot of damage. It all depends on the balance of your garden ecosystem.
Read on to learn about this unique soil-dwelling crustacean, their role in the garden, and how to organically control them if they get out of hand.
What Are Pill Bugs?
Pill bugs are scientifically classified as isopods or non-insect arthropods. They have an armored exoskeleton, seven pairs of legs, and jointed limbs. Interestingly, they are technically terrestrial crustaceans, which are distant relatives of lobsters, shrimp, and crabs!
They are native to Europe and technically invasive to the United States. They have naturalized pretty much everywhere thanks to their generalist diet and resilient protective exoskeleton.
I like to think of them as little armadillos. Perhaps that’s why their Latin name is Armadillidium vulgare. These bugs have a crusty exoskeleton that protects them when they roll up into a ball (when they look like a pill). This rolling is their primary defense mechanism and the source of their most common name “rollie pollie.” They are also called woodlouse because of their common residence in forests.
If you want to understand the role of pests (or any organism) in your garden, you have to look at their life cycle and reproduction. At a closer glance, they have even more fascinating traits than just rolling up in a ball.
There are three main stages to the pill bug life cycle:
Eggs: The female pill bug carries her eggs in a marsupium (a pouch kind of like a kangaroo). The bundle of eggs is called a brood and may have 100-200 eggs at a time. It takes 3-4 weeks for eggs to hatch and females produce 1-3 broods annually.
Young: Once eggs hatch, the young stay in their mother’s pouch surviving off of nutrients from the marsupial fluid. When they reach 2 mm in length, the little white babies venture off on their own and go through a series of molting and growth.
Adult: Adults grow up to 18 mm long and live for two to five years. Their main host plants are dead and decomposing, however they sometimes eat seedlings or roots of tomatoes, radish, lettuce, mustards, peas, and beans.
You will probably recognize rollie pollies in your garden based on childhood experiences. But if you need a refresher, identifying them is a breeze:
- Color: Gray to Brown
- Size: 8 to 18 mm long (at maturity)
- Antennae: 1 pair
- Legs: 7 pairs
- Shape: Oval or pill-shaped when walking, ball shaped when rolled up
- Texture: Segmented exoskeleton like an armadillo
Pill bugs are nocturnal isopods that are mostly active at night or in the shade. During the day, they prefer dark, humid places under logs or mulches. In these protected areas, they can hide from predators and gorge on their favorite food: decomposing organic matter.
They live close to the soil and rarely climb. They sometimes burrow or take shelter in cracks and crevices, but they mostly hang out at ground level, sometimes making their way into shallow raised garden beds. They love compost piles and heavily mulched areas of gardens.
What Do They Eat?
Pill bugs mainly eat decaying plant material like leaves and decomposing matter; basically just dead stuff. They are part of the massive garbage disposal system of nature.
However, if their populations get out of hand or no decaying matter is available- they turn to live plants. Hungry pill bugs will eat the stems of weak seedlings or dying leaves of struggling garden plants. Tomatoes, radishes, lettuce, peas, and beans are the most likely to be eaten by them if decomposing leaves are not available.
Are They Good for My Garden?
As detritivores (consumers of dead plant material), pill bugs have actually been found to be beneficial to hardwood forests because they facilitate faster nutrient cycling and mineral availability.
In your garden, they could be beneficial to the soil food web. This is especially relevant in lasagna-style gardens that have large quantities of organic matter available for decomposition.
When Are They Bad?
The average population will be neutral or beneficial. But sometimes things get out of whack in the ecology and their numbers can rapidly skyrocket.
Though uncommon, pill bugs can become especially problematic if your garden does not have much mulch or decaying material for them to eat. As long as your garden has nice mulch-covered soil and plenty of decomposing organic matter, they should remain good neighbors.
Hungry rollie pollies are great in the compost pile or lasagna garden (they accelerate the breakdown process), but not so great among new seedlings.
Getting Rid of Them
If pill bugs start to get out of control and eat your plants, don’t panic!
You probably don’t want to remove all the pill bug habitat in your garden, as that would be very time-consuming and potentially remove habitat for other beneficial insects.
Instead, try a few of these methods around just the areas of the pill bug outbreak:
Organic Pest Control
Food Grade Diatomaceous Earth
Diatomaceous earth is a fine powder of ground-up shells. It is microscopically sharp and will cut virtually all insects, causing them to dehydrate. It is harmless to humans and plants, you just don’t want to breathe in a cloud of diatomaceous dust. Carefully sprinkle diatomaceous earth around the base of plants to protect them. You will have to reapply if it gets wet.
Neem is a common preventative for many pests because it tastes and smells bad for bugs. Neem is mildly poisonous to rollie pollies but completely safe for humans. Just be sure to apply at the recommended rate and use an OMRI-approved (safe for organics) neem product.
Lure Them Away
Sluggo and other slug bait products are safe organic options for luring pill bugs away from your plants. They use fermentation of a naturally occurring soil bacteria called Saccharopolysporo spinosa (or Spinosad) to lure and kill them.
Beer traps used for slug baiting are also fairly effective. Simply get a shallow plastic container, fill it with cheap beer, and bury it in the soil at surface level so the bugs fall in and drown.
Garden Waste Baits
You can also move them to another location by luring them with decomposing leaves, corn cobs, or rotting melons. Put a pile of decaying plants near the infested area, let them migrate over, then collect it all with a shovel and move to your compost pile or out of your garden.
Ultimately, the easiest way to keep them away from your plants is to clean up dead plant debris around your crops and avoid overwatering. Pill bugs are great to have in pathways or perennial beds, but you don’t want them near your seedlings. Moist soil conditions and lots of decaying plant matter will magnetize them. Cleaning your vegetable garden beds should do the trick!
At the end of the day, rollie pollies are not a threat to your vegetable garden! With proper management, you can even use them to your advantage with perennial mulches and compost piles.