Garden slug

The garden slug (Arion hortensis) belongs to the phylum Mollusca, class Gastropoda, family Arionidae. It is a terrestrial mollusk without a shell, typically growing to a length of 30–40 mm. Its body color ranges from dark grey to brown or black, while the sole of the foot is distinctively bright orange or yellow. These pests are primarily nocturnal and thrive in high-humidity environments.

This species is a generalist feeder (polyphage) that damages a wide variety of agricultural crops. Vegetables such as lettuce, cabbage, and cucumbers are highly susceptible, as are root crops like potatoes, carrots, and beets. Strawberries and ornamental flowers are also frequently attacked. The damage is particularly severe during wet springs and autumns, affecting both greenhouse and field-grown plants.

The biology of the garden slug is heavily dependent on moisture. They reproduce by laying eggs in clusters of 10–30 within moist soil or beneath organic debris. The life cycle involves several developmental stages, with both adults and eggs capable of overwintering in the soil at depths of 10–15 cm. This ability to survive in protected soil layers makes them difficult to eradicate completely.

Signs of infestation include irregular holes in leaves and deep, gouged cavities in fruits or tubers. A characteristic slimy, glistening trail often identifies the path the slug has taken. Beyond the physical loss of plant tissue, the feeding wounds create entry points for various bacterial and fungal pathogens, significantly reducing the marketability and storage life of the harvest.

Integrated pest management strategies are recommended for control:

• Maintaining clean garden hygiene by removing plant debris and boards where slugs hide.
• Creating physical barriers like crushed eggshells, wood ash, or gravel around vulnerable plants.
• Regular soil cultivation to disrupt egg-laying sites and expose slugs to predators.
• Applying molluscicides containing iron phosphate, which are safe for most garden environments.