Spanish slug

The Spanish slug (Arion vulgaris) is a highly invasive mollusc species that poses a significant threat to gardens, agriculture, and local biodiversity. Belonging to the order Stylommatophora and the family Arionidae, this species has successfully colonized large parts of Europe, demonstrating high adaptability to various climates and human-modified environments.

This pest is a generalist herbivore, capable of consuming a vast array of plant material. Its primary targets include leafy greens like lettuce and cabbage, strawberries, potatoes, and various ornamental flowering plants. In many cases, it can cause total crop failure if the population density is high enough to strip young seedlings overnight.

The biological cycle of the Spanish slug typically lasts one year. They are hermaphroditic and highly prolific, with a single individual laying hundreds of eggs in batches during the damp summer and autumn months. Juveniles emerge quickly under favorable humidity conditions, growing rapidly and reaching sexual maturity before the onset of winter.

Damage caused by this slug is characterized by large, irregular holes in leaves, stems, and fruits. Beyond physical destruction, they deposit copious amounts of slime, which degrades the aesthetic and sanitary quality of harvested vegetables. Furthermore, their trails facilitate the entry of pathogens and spores, significantly increasing the risk of secondary infections, such as soft rot, in damaged crops.

Effective management requires a strategic, integrated approach to minimize population pressure:

• Maintaining clean cultivation areas by removing debris and weeds.
• Implementing physical barriers, such as copper tape or abrasive surfaces.
• Using biological controls like predatory nematodes (e.g., Phasmarhabditis hermaphrodita).
• Encouraging natural predators such as hedgehogs, frogs, and ground beetles.
• Targeted application of approved molluscicides containing iron phosphate.