Woodlice
Grey, many-legged crustaceans that mostly eat dead plant matter but also nibble seedlings, soft roots and fruit resting on damp soil.
Also known as: Pill bugs, Slaters, Roly-polies
Symptoms and identification
Seedlings are eaten off at the base, and ripe strawberries, cucumbers and squash touching the soil have holes and rough, shallow gouges. The animals are grey, oval and flat and roll into a ball or scurry away when disturbed, and are found in damp, dark places.
Causes
Woodlice need moist places and shelter from the light, so they build up under pots, boards, thick mulch and plant debris, especially in damp weather and in greenhouses.
Organic treatment
Trap them under an upturned flowerpot of damp straw or half a potato, and move the catch away each morning. Protect seedlings with collars until they are established.
Prevention
Clear debris and old boards, and do not leave pots and trays sitting in damp heaps. Raise fruit off the soil with straw or mesh, and let the soil surface dry between waterings.
Chemical treatment (use with care)
Chemical control is rarely needed. Woodlice also break down decaying matter and compost, so leave them alone unless they are damaging seedlings.