Sowbug

Roly-poly, pillbug, doodlebug, or sowbug, whatever you call them, the more you know about these creatures, the weirder they get.


First, they are not really bugs. They are crustaceans, making them cousins to lobsters and armadillos. Just kidding - they are not related to armadillos. [Thank you Gary!]. They look like they should be, though. Did you know that sowbugs and pillbugs are not the same thing? I didn't either.

Pillbug (Kate Russell)

Pillbugs

Both species have 14 legs and breathe through trachea-like gills in their feet, but sowbugs have tails and pillbugs do not. Also, like armadillos, pillbugs can roll up into a ball when disturbed. Sowbugs cannot do this. More importantly, pillbugs enjoy eating green plant material. Their diet includes all parts of your beans, beets, chard, corn, cucumbers, lettuce, melon, spinach, squash, and strawberries, and potato tubers. While pillbugs eat stink bug eggs and help break down nutrients, they can be pretty destructive in the garden. These pests can chew tender seedlings down to the ground in a single feeding. Most of this feeding is done in the evening and at night.

​Bottom line: if they can curl up, step on them. If they don't curl up, leave them alone.

Pillbug eating stink bug eggs on zucchini leaf (Kate Russell)

Pillbug feeding on (and hiding in) Gerbera daisy (Kate Russell)

Sowbugs

Sowbugs, or woodlice, mostly eat dead plant material, helping with composting and decomposition. Female woodlice carry fertilized eggs in a marsupial pouch, like a kangaroo. They can also reproduce asexually.


These fascinating creatures can live for several years, producing two or three generations each year. Each brood can include 30 to 80 offspring. In particularly rainy years, pillbugs can be a problem in the garden.

Sowbug (Larry & Teddy Page) CC BY 2.0

Woodlice and pillbugs prefer cool, dark, moist places - under planters, bricks, hoses, dense vegetation, whatever they can find. Having evolved from sea-going crustaceans, such as lobster and crab, water is critical to their survival. [Note: don’t eat them. Wikipedia says they taste similar to “strong urine." I don’t know how they found out, and I am certainly not going to try it myself!]


​While pesticides can be effective against pillbugs, there are better control methods. The best way to reduce pillbug populations is to reduce dark, moist hiding places, and to keep mulch and other dead plant material away from seedlings, until they are large enough to survive being gnawed by a pillbug. Diatomaceous earth can also be used as a deterrent and some slug and snail baits are effective.