Large red slug

The Arion rufus, commonly known as the large red slug, is a significant gastropod mollusc belonging to the family Arionidae. It is recognized as a major invasive pest in many temperate regions, thriving in moist environments such as gardens, greenhouses, and humid forest margins.

This slug is a generalist feeder that damages a wide variety of plant species. The primary crops affected include leafy vegetables like lettuce and cabbage, strawberries, potatoes, and ornamental flowers. They pose a particular threat to seedlings, which can be completely devoured within a single night.

The biology of Arion rufus is characterized by its nocturnal activity and preference for damp habitats. They are hermaphroditic and lay batches of eggs in moist soil crevices or under decaying vegetation. Populations tend to explode during wet seasons, leading to significant economic losses in gardening and commercial vegetable production.

Damage is typically observed as irregular holes in foliage, stems, and fruits. Beyond mechanical consumption, the presence of these slugs is marked by the trail of mucus they secrete while feeding. This slime not only degrades the aesthetic quality of ornamental plants but also significantly increases the risk of plant diseases and fungal contamination.

Effective control measures require a combination of preventative and corrective strategies. It is essential to keep garden beds free of debris and dense weeds to eliminate hiding spots. Physical barriers like crushed eggshells or copper tape can be effective on a small scale. For larger infestations, applying specialized molluscicides or setting up beer traps is recommended to maintain the population at a manageable level.