Our land-based crustaceans never live in water and are the pillbug and sowbug, which are part of the Isopod order and in their case, also in the suborder Oniscidea (iso means equal, and pod means foot). In the case of the pillbug and sowbug each leg of their seven pairs is basically identical in size and shape to the other, so there you go. To make it even more interesting, Isopods, including our pillbug and sowbug, breathe with gills or pseudotrachea, which is why you’ll find them in moist areas with high humidity such as under rocks, mulch, or compost piles. That need for moisture and high humidity is one of the reasons they normally feed at night and hide during the day.
Now, you probably don’t want to boil up a pot of these as you would crayfish or shrimp because beyond their very small size, with adults ranging from one-quarter to three-quarters of an inch, it’s said you would end up with a foul smelling and tasting mess, unlike the delicate awesome flavor of crayfish or shrimp. Don’t you have to wonder about the person who figured that one out?
You might be saying, “aren’t the pillbug and sowbug the same insect?” Actually no, they are two slightly different insects. Both have a shell-like exterior made up of a series of segmented plates, with the three typical parts of an insect the head, thorax and abdomen, and their overall color ranges from dark gray to white. The differences between the two are that sowbugs have two tail-like appendages sticking out the back that are easily seen, but not so for the pillbug. Also, the pillbug, unlike the sowbug, can roll up into a ball, which is why many people call them roly-polies. As a side note, it takes two years for them to become adults and they can live for two years.
OK, so that’s all interesting, but so what? While mostly a beneficial scavenger that feeds on decaying organic plant matter, both the pillbug and sowbug will, especially if numbers are high, feed on seedlings — often totally dismantling them. They will also feed on the outside surfaces of fruits and vegetables, especially those lying on the ground.
A while back, I had one of our large greenhouse producers call me about new vegetable transplants that kept disappearing or being partially eaten time and time again without the greenhouse workers being able to determine what was causing the problem. We discussed possible options including the pillbug. One night they went out with flashlights and low and behold there was a mass of pillbugs having a dinner of the newly planted transplants.
Admittedly, this is one of those insects most people see as just something found periodically in the garden and not as a potential pest, and it’s true that once plants achieve some size, pillbugs and sowbugs usually won’t bother the plants themselves. However, they could damage produce lying on the ground. So what might you do if there is a problem? Avoid mulches around seedlings and water early so things dry by nighttime. If you have plants like strawberries or cucumbers figure out a way to raise them up off the soil using something like straw, which is more open and dries out quickly. With plants like cucumbers, consider growing them on some type of fencing. Should pillbugs come indoors, remove debris, wood or other materials by the house, and chalk any cracks or openings around the outside of the house.
So, enjoy your land-based crustaceans, and here’s wishing you all a great summer!
Thought for the day: “I want to lose weight by eating nothing but moon pies, which have significantly less gravity than earthier foods such as fruits and vegetables.” — Jarod Kintz.
Previous articles are available at The Times-Independent website, www.moabtimes.com. Have an idea you’d like Mike to consider writing about? Want more information about these topics? Call the Utah State University Extension Grand County office at 435-259-7558 or email Mike Johnson at firstname.lastname@example.org.