Small grey slug

Taxonomic position. Arion distinctus, commonly known as the small grey slug, belongs to the class Gastropoda, order Stylommatophora, and the family Arionidae. This species is widely recognized as a significant pest in agricultural, horticultural, and domestic garden environments, often causing widespread damage to various types of vegetation.

Biology and life cycle. These slugs are hermaphroditic and are primarily nocturnal, favoring damp and sheltered habitats. Reproduction occurs throughout the growing season, with eggs deposited in clusters within moist soil or beneath organic debris. The life cycle typically spans one year, and the species is capable of overwintering as both adults and eggs, ensuring rapid population recovery each spring.

Crops damaged. As a polyphagous pest, Arion distinctus feeds on a wide range of plants. It is particularly damaging to leafy vegetables, such as lettuces and brassicas, root crops, including potatoes and carrots, and various herbaceous ornamentals. Soft fruits like strawberries are also highly attractive to them, especially during humid weather conditions.

Nature of damage and harmfulness. The damage is characterized by irregular holes in foliage, often consuming significant portions of the leaf surface. On storage organs or fruits, the slug creates deep pits or excavations, rendering the produce unmarketable. Furthermore, the presence of their slime trails and feeding wounds often encourages the development of bacterial and fungal rots, leading to further loss of yield.

Protection measures. Integrated pest management (IPM) is essential for controlling Arion distinctus:

• Maintain garden hygiene by removing debris where slugs shelter.
• Install physical barriers such as copper tape or abrasive surfaces like grit around vulnerable plants.
• Use iron phosphate-based baits which are effective and environmentally safer.
• Encourage natural predators such as hedgehogs, ground beetles, and thrushes.
• Implement proper irrigation management to avoid excessively moist conditions in susceptible areas.