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Pest of the Month - Pillbugs

Pest of the Month - Pillbug, Nebraska Extension Acreage Insights for May 1, 2018,
Brown sowbug. Image by Judy Gallagher,

A Rolly Pollie by Any Other Name

When we go outside and flip over logs or rocks there are several creatures we may expect to see. One of the most famous (dare I say, most adorable) is the arthropod colloquially known as a “rolly pollie”. Their short, many legged bodies and ability to roll up are a delight and they are the first outdoor pet that some folks collect as children. Due to their appearance it may be assumed that they are a short millipede, but they are actually “isopods” and are a type of crustacean. They are more closely related to shrimp than they are to a millipede! They do have oceanic relatives, known as giant isopods which look like a rolly pollie on steroids.

iPest of the Month - Pillbug, Nebraska Extension Acreage Insights for May 1, 2018, comparison of a pillbug and a sowbug. Note the color differences as well as the two “tails” the sowbug has (photo by Jim Kalisch; UNL Entomology)

There are two arthropods that may be called a rolly pollie; pillbugs or sowbugs. Pillbugs are usually a darker slate color compared to the tan color a sowbug has. Sow bugs are also mottled, or speckled, which gives them a distinct look compared to the pillbug. They also have two little “tails” that poke out of their back end. Finally, sow bugs are not true rolly pollies as they can not roll up like the pill bug can.

Generally speaking, we consider pillbugs and sowbugs to be beneficial decomposers. Their preferred habitat is damp, dark areas and they consume lots of rotting materials to help clean up the environment. However, there are times where they can become pests. One example is when they enter a structure and wander around looking for a place to live. It’s best to just vacuum up or sweep up these pill bugs as you see them. While doing that look for the entry point they have to get into your home and seal it up with a caulk or silicone putty. If their populations are high enough, pillbugs can also cause damage to gardens or to new landscape plants as they nibble on them. The best method to prevent this or to reduce their populations, is sanitation. Cleaning up leaves and other detritus removes their harborage and will help to dry out the area. This drives them to other spots where they will cause less damage. Diatomaceous earth applied near plants that need to be protected will help to deter pill bugs. Overall though, it’s best to live with them as these odd land-crustaceans help to keep our environments happy and healthy.

Image of Jonathan Larson
Jonathan Larson
Extension Educator - Entomology

Jonathan Larson is the Nebraska Extension entomologist for Douglas and Sarpy counties. His main focus is lawn and landscape pests but he also helps with bed bugs, roaches, and any other home invader that has six or more legs. Jonathan has his Bachelor of Science in Entomology from Purdue University, and his Ph.D. in Entomology from the University of Kentucky.

Contact Jonathan at:
Douglas/Sarpy County Extension
8015 W Center Rd.
Omaha, NE 68124-3175
(402) 444-7804