Deroceras reticulatum

Derosceras reticulatum

Biological Name

Deroceras reticulatum

Common Name

Grey field slug

Other Common Name

Grey garden slug

Appearance/Characteristics

The grey field slug is very variable in colour, 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.

Other Similar Species

Deroceras rodnae, Deroceras praecox and Deroceras turcicum


 

Biological Notes

Each slug can lay up to three hundred eggs, which can hatch in as little as two weeks.

Life cycle covers a few months, usually two generations. The main reproductive phase is in summer and autumn. They normally survive for around a year and are killed by frosts. However the eggs are very resilient and survive overwinter and in drought conditions to ensure the next generation.

Geographical Distribution

The grey field slug is native to the European region, North Africa and the Atlantic Islands. It occurs widely in Europe in open agricultural areas. Countries where it is a significant agricultural pest include Great Britain, Ireland, Austria, Bulgaria, Czech Republic, Netherlands, Poland, Slovakia.

Habitat

The grey field slug is almost exclusively restricted to cultivated areas, usually in open habitats, in agricultural fields and meadows, near roadsides, gardens and parks. It shelters under stones and ground litter This is the most common species found in agricultural crops and is more active above ground than the other common species

Crops at Risk

This species is omnivorous, feeding mainly on fresh leaves and fruits or seedings. The grey field slug is a serious pest of agricultural crops, garden cultivations and horticulture.

Oilseed rape is particularly at risk but also winter cereals and potatoes.

Damage Caused/Symptoms

Damage can range from complete crop loss where seedlings are consumed to reduction in yield or quality. Reduction in quality can cause real economic loss when it occurs on fruits such as strawberries.

Impact and Severity

This is the most damaging of species.

Prevention and Control

There are a number of cultural methods that can be employed to help minimize the risk of damage from this slug.

  • Ploughing buries available food sources and also directly reduces slug populations
  • Removal of the trash and weeds between crops reduces the food source for slugs
  • Work seedbeds to a fine tilth – cloddy fields will allow slugs free movement through the soil, attacking seeds and the seedlings’ growing points
  • Ensure seedbeds are firm; if possible roll after drilling
  • Cultivate soon after harvest, especially in dry conditions

Application of AXCELA® pellets in accordance with label instructions in a timely manner will then control any remaining threat.

Natural Predators

Various carabid beetles are predators of Grey field slug, including:

  • The European garden beetle Carabus nemoralis, is a beneficial predator because it eats the young of this species and also their eggs.
  • The common black ground beetle Pterostichus melanarius is an important predator in agricultural crops eating both juvenile slugs and their eggs.