British Wildlife Wiki

The Grey Field Slug (Deroceras reticulatum), is a species of small air-breathing land slug. It is important as an agricultural pest.

Deroceras reticulatum

Grey Field Slug - D.Skingsley


The native distribution of this slug species is Europe, North Africa and the Atlantic Islands.

It is widely distributed in Europe, more rare and restricted to cultivated fields in the southeast, particularly in the Balkans, probably absent from Greece and Bulgarian mountains. In North and central European lowlands, Great Britain and Ireland it is probably the most widely distributed slug. It is scarce and mainly as a synanthrope in north Scandinavia.


As all other Deroceras it has a short keel at the back of the body. Deroceras reticulatum is very variable in color, creamy or light coffee cream, rarely blackish spotted (slugs with spots may appear blackish). Behind the mantle there is the dark spots form a reticulate pattern. The skin is thick. Mucus is colourless, on irritation milky white.[1]The slug cannot be distinguished from many other Deroceras species based only on its external appearance.

This slug can be up to 40–60 mm long (preserved 25–30 mm).[2]The size varies according to the habitat.

Reproductive system: Penis is fleshy and with a silky sheen, in the shape of an irregular sac, in fully mature specimens divided into 2 parts by a deep lateral constriction. Penial gland has very variable shape, usually a few branches or a single long branch. Stimulator is large, conical and narrow. Retractor of the penis is inserted laterally. Vas deferens opens into penis wall facing the external body side.Rectal caecum is large.

It can travel up to 40 feet (12.2 m) in a single night.



Deroceras reticulatum is at present almost exclusively restricted to cultivated areas, usually in open habitats, in meadows, near roadsides, in ruins, gardens and parks, not inside forests. It shelters under stones and ground litter (does not burrow into the soil). It is active at night

Feeding habits[]

This species is omnivorous, feeding mainly on fresh leaves and fruits or seedings. Deroceras reticulatum is a serious pest of agricultural crops, garden cultivations and horticulture. After several years with continuous moist weather conditions abundance can seriously increase.

Life cycle[]

Life cycle covers a few months, usually two generations.[3]The main reproductive phase is in summer and autumn. It lays hundreds of eggs which hatch during early summer.

Maximum age is about a year.[4]Slugs die at the first frosts.[5]Usually only eggs hibernate, sometimes also juveniles.


Various carabid beetles are predators of Deroceras reticlatum