Pillbugs (Roly-Polies)
Armadillidium vulgare
📖 Description
Pillbugs, also known as roly-polies, are terrestrial crustaceans that are primarily beneficial decomposers feeding on decaying organic matter. However, in moist environments with high populations and limited decaying matter, they can become plant pests by feeding on tender seedlings, roots, and fruits that contact the soil. Their damage is most common in overwatered gardens, greenhouses, and indoor containers where they thrive in consistently moist conditions. Because they are crustaceans, not insects, many insecticides are ineffective against them. The key to managing pillbug damage is reducing moisture and removing their habitat rather than chemical control.
⚠️ Symptoms to watch for
- Irregular holes in seedling stems at ground level,Chewed tender roots and root vegetables,Damage to ripening strawberries resting on soil,Holes in tender leaves touching the ground,Presence of gray, oval creatures rolling into balls when disturbed
🩹 Treatment
- Remove hiding places like boards, pots, and thick mulch (organic),Reduce watering frequency and improve drainage (organic),Apply diatomaceous earth around plant bases (organic),Set out traps with cut potato halves and dispose in morning (organic),Use iron phosphate bait (organic),Apply permethrin barrier spray if severe (chemical)
🌿 Organic treatments
- Remove hiding places like boards, pots, and thick mulch,Reduce watering frequency and improve drainage,Apply diatomaceous earth around plant bases,Set out traps with cut potato halves and dispose in morning,Use iron phosphate bait
🧪 Chemical treatments
- Apply permethrin barrier spray if severe
🛡️ Prevention
- Improve garden drainage and avoid overwatering,Use drip irrigation instead of overhead watering,Keep mulch away from direct contact with plant stems,Elevate fruits like strawberries off the ground with mulch or supports,Remove decaying plant material that provides habitat,Use coarse mulch instead of fine, moisture-retaining types
🪴 Affected plants
- Seedlings,Strawberries,Tender Root Vegetables,Cucumbers,Beans,Indoor Plants
🦋 Natural predators
- Spiders,Centipedes,Birds
🌱 Host plants
- Various seedlings,Strawberries,Decaying matter
🔄 Lifecycle
- Females carry 20-50 eggs in a brood pouch (marsupium) on their underside.
- Eggs hatch in 3-7 days, and young remain in the pouch for 1-2 weeks.
- Juveniles molt repeatedly over 4-5 months before reaching maturity.
- Adults live 2-3 years and can produce 2-3 broods per year.
- They require moist environments and are active primarily at night.
- Unlike most crustaceans, they breathe through gill-like structures that must remain moist.
📅 Season
- Year-round (most active in moist, warm conditions)
🔎 Appearance
- Oval, segmented, gray crustaceans that roll into a ball when disturbed.
- Seven pairs of legs.
- Often confused with sowbugs, which look similar but cannot roll into a ball.
- Both are crustaceans (not insects) related to shrimp and crabs.
💥 Damage level
- Low
🔁 Reproduction rate
- Moderate
🗺️ Geographic regions
- North America
- Europe
- Asia
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