Pillbugs in garden debris
Pillbugs feeding on gomphrena at night
Pillbugs feeding on shallot (Allium cepa) foliage at night
Pillbugs on a duct tape collar trap
Overview
Sowbugs (Porcellio laevis) and pillbugs or roly-polies (Armadillidium vulgare), sometimes called “woodlice” are outdoor creatures that are often mistaken to be insects. They range in size from ¼ to ½ inch long and are dark to slate grey with seven pairs of legs. Sowbugs have a pair of tail-like appendages but pillbugs do not. Pillbugs can roll into a ball when disturbed. This behavior has given them the common name of “roly-polies”
Sowbugs and pillbugs live their lives in moist environments. Common places for them to live would be under mulch, compost, stones, flowerpots, and other places on damp ground. Some places the creatures may explore would be damp basements and first-floor levels and garages. They do not bite people or damage structures. They can damage plants in a greenhouse in high numbers. Sowbugs and pillbugs are scavengers and their main source of food is decaying organic matter, but they can feed on live plant material when populations are high and the availability of decaying plant material is small. If you suspect that pillbugs are eating your plants, go outside at night and check with a flashlight.
They are actually crustaceans that have adapted to living their life on land. They are closely related to lobsters, shrimp, and crayfish and have gills.
Life Cycle
Eggs are laid by females and are carried in a pouch beneath the body. Young sowbugs and pillbugs, much like the adults, hatch from the eggs. The young remain in the pouch for up to 2 months after hatching. In about a year they grow to maturity and breed mainly in the spring. They may live up to 3 years and have up to 3 broods.
Integrated Pest Management Strategies
1. Limit entry indoors. The best control to limit indoor entry is to reduce moisture near the foundation. Mulch, leaves and other plant debris needs to be cleared because this material attracts sowbugs and pillbugs. Don’t allow moisture to accumulate neat the foundation. Make sure that you have diverted water away with working gutters, downspouts and splash blocks. Seal entry locations by caulking cracks or other small openings.
2. Repot plants in infested soil. If found in pots indoors or out, simply tip the plant out of the pot, scrape off the soil, and replant in fresh soil.
3. If found outdoors. Sowbugs and pillbugs generally do little or no harm to plants. In large numbers, they can feed on plants or small roots if no preferred food source is available. Protect young seedlings with paper towel collars, duct tape collars, or waiting until the plants are large enough to transplant. Providing enough decaying organic matter in high-population areas can help prevent live plant damage. If you have a compost pile, you can set up a trap that is damp and dark with decaying organic matter and relocate pillbugs to your compost pile as they are great composters.
4. Insecticides can be used when all else fails. Applying insecticides such as Sevin, and Permethrin (Spectracide Bug Stop) can be accomplished with a compressed air or hose end sprayer.
Organic Strategies
Strategies 1, 2, and 3 are strictly organic approaches.
Pesticide Disclaimer:
Always follow the product's label and ensure the product is effective against pillbugs/sowbugs. Not following the pesticide label before usage is a violation of federal law.