Roly-polies, also known as pill bugs or woodlice, are common inhabitants of garden ecosystems; they are technically terrestrial crustaceans, not insects. These small, segmented creatures are often found in dark, damp places. When populations become excessive, roly-polies can cause noticeable damage to vulnerable plants and crops. Understanding the methods that eliminate these inhabitants is the first step toward protecting delicate seedlings and produce.
Understanding Roly-Polies: Friend or Foe?
Roly-polies primarily function as decomposers, feeding on soft, decaying organic matter such as leaf litter, old mulch, and dead plant material. This diet helps recycle nutrients back into the soil, which is beneficial for the garden ecosystem. They are nocturnal creatures, seeking high-humidity environments during the day to maintain the moisture levels necessary for their survival as terrestrial crustaceans.
The shift to a garden pest occurs when populations grow too large or when conditions become too dry. If decaying matter is insufficient or soil moisture is low, roly-polies will turn to tender, living plant tissue for hydration and food. They feed on new sprouts, young seedlings, and soft fruits resting on the ground, such as strawberries. Damage is typically seen as irregular holes chewed at the base of young stems or on the surface of ripening produce.
Modifying the Environment for Prevention
Long-term control focuses on eliminating the dark, moist habitats roly-polies require to thrive and reproduce. Reducing excess ground moisture is a primary strategy, accomplished by improving soil drainage or adjusting watering schedules. Watering in the early morning allows the soil surface and plant foliage to dry out before nightfall, when these pests are most active.
Removing organic debris from around vulnerable plants reduces both shelter and food sources. This includes clearing piles of fallen leaves, grass clippings, and old, decomposing mulch lying directly against seedlings or foundations. If mulch is necessary, using a thinner layer or pulling it back from plant stems helps expose the soil to sunlight and air. Good air circulation, achieved through proper spacing and pruning, also discourages the damp conditions roly-polies prefer.
Non-Chemical Removal and Physical Barriers
Direct, non-chemical methods offer immediate action to reduce existing roly-poly populations. Hand-picking is effective in small garden areas, especially since the pests often cluster under rocks or boards during the day. Collected roly-polies can be dropped into a container of soapy water for quick elimination.
Simple, passive traps utilize the roly-polies’ attraction to moisture and decaying food sources. Placing hollowed-out raw potato halves, melon rinds, or damp, rolled-up newspapers cut-side-down in the garden overnight will attract the pests. Checking these traps each morning allows for easy collection and disposal of the clustered organisms.
Physical barriers provide a protective ring around individual plants or beds. Diatomaceous earth (DE), which must be food-grade, is a fine powder composed of fossilized aquatic organisms. DE works by physically abrading the roly-poly’s outer layer and absorbing moisture, leading to dehydration. Because moisture neutralizes its effectiveness, DE must be reapplied after rain or heavy watering. Copper tape is another barrier option, as the metal reacts with the roly-poly’s body chemistry to produce a mild electrical charge that deters them from crossing.
Targeted Pesticide Application
When environmental and physical controls are insufficient for managing a large infestation, targeted application of chemical products can be used. Iron phosphate baits, often marketed for slug and snail control, are also effective against roly-polies. These baits work when ingested and are considered safer for pets and wildlife than some other chemical options. The pellets should be scattered sparingly where roly-polies are actively feeding or congregating, such as under containers or along bed borders.
Other options include contact insecticides containing active ingredients like pyrethrins or carbaryl, sometimes labeled for woodlouse or sowbug control. These products only eliminate the organisms they directly touch, which is challenging since roly-polies hide under debris during the day. Due to the broad-spectrum nature of contact pesticides, application should be highly localized to the infestation site to limit impact on beneficial insects. Always follow the product label instructions carefully, especially concerning reapplication rates and safety precautions around food crops.