Woodlice

Woodlice, also known as slaters and pillbugs, are abundant animals in most gardens and greenhouses. They cause little or no damage to plants. Large numbers often occur in compost heaps, where they help break down the plant material and are a useful part of the composting process.

Woodlice

Quick facts

Common name Woodlice
Latin name Various species, including Armadillidium, Oniscus, Philoscia and Porcellio species
Plants affected Occasionally seedlings and strawberry fruits
Main symptoms Small holes eaten in young leaves and soft fruits
Caused by Terrestrial crustaceans known as woodlice
Timing All year

What are woodlice?

Woodlice are terrestrial crustaceans that shelter in dark damp places, especially where there are accumulations of decaying plant material.

Symptoms

Woodlice are not usually plant problems, but they are often found in damage caused by other animals. Woodlice occasionally damage soft plant tissues, such as seedlings and sometimes strawberry fruits.

Holes in older, tougher plant material will have been caused by something else, such as slugs or caterpillars.

Control

 

  • Woodlice are not significant plant pests and are useful recyclers of decomposing vegetable matter
  • They are naturally abundant in a healthy garden
  • Control is therefore not usually necessary
  • Woodlice can come into houses from gardens but are unlikely to survive for long indoors unless they can find a damp place to shelter.
  • Keep greenhouses tidy to avoid creating too many damp hiding places for woodlice. Remove dead flowers and leaves.
  • Woodlice have many natural enemies, such as shrews, toads, centipedes, some spiders, ground beetles and parasitic flies

Biology

During the day, woodlice hide in dark damp places so they are often found under logs, stones and flower pots. At night they move around in search of food, which is mainly rotting plant material.

There are several species of woodlice commonly found in gardens. They are up to 1cm (½in) long and are often grey in colour, with the body segments sometimes flecked with yellow or pinkish brown markings. Some species, known as pillbugs, can roll themselves into a ball when threatened.

Woodlice produce eggs in spring and these are retained inside the female’s body until they hatch. The newly hatched woodlice are kept in a brood pouch on the underside of the female for a few days before they disperse.

Immature woodlice are similar in appearance to the adults and they shed their outer shells on a number of occasions as they grow bigger. They become adults by late summer and overwinter before reproducing in their second year.

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