Updated eradication instructions will be published in April 2026.

In most cases, it is possible to combat the spread of the slug with rather small measures. In the worst cases, however, even large masses of soil need to be treated to destroy the slug population.

The control of the Spanish slug is most effective in the spring before the overwintered individuals have laid eggs. A slugl lays about 20 to 30 eggs at a time and continues to lay eggs throughout the summer and autumn during the wet seasons. Therefore, th slugs in reproductive age should be destroyed immediately in the spring and always before laying eggs.

In home gardens, Spanish slugs can be collected with, for example, barbecue pliers, which protect against the addhesive, sticky mucus. Because of the risk of infection (listeria, E.coli), disposable gloves should be worn when handling snails. Collecting slugs can be made more efficient by placing, for example, boards or jute bags on the ground to collect moisture and thus to attract and gather slugs.

Mollusks have a developed nervous system and probably the ability to feel pain. Since the Animal Welfare Act states that animals must not be subjected to unnecessary suffering, Spanish slugs must be killed as quickly as possible. Effective and recommended methods of killing include cutting the head of a slug with scissors longitudinally between the sensory horns, causing the nerve ring of the head to break, or crushing the head of a slug with sufficient force e.g. with a stone on a hard surface so that the impact is as effective as possible. Also, it is recommended to stun a slug in mild (5%) and kill in strong alcoholic solution (e.g. denatured spirit, ethanol content above 80%). Slugs can also be killed, like crabs, by dropping them one by one into boiling water, so that the water should boil vigorously all the time. Alternatively, you can pour plenty (at least double amount) of boiling water over the snails. Also, 10% spirits vinegar solution or freezing has been used to kill slugs, but they are not recommended for use. Salt or other low-intensity toxins must not be used. Also, slugs should not be buried alive, nor cut across, as then the front end can survive. Dead slugs should be packed well and delivered for incineration with mixed waste.

For control of slugs, iron phosphate preparations and biological nematode preparations are available for use in arable and horticultural crops in fields, in the garden and in the greenhouse. Some products are also allowed for consumer use.

In large affected areas, the soil infested by slugs is peeled at a depth of 10 cm. The exfoliated soil is poured into an excavated pit or piled up in heaps on the spot. The pit and soil piles are covered with a thick layer of soil. A half a meter thick layer of soil is probably sufficient. Compaction increases the effectiveness of the soil layer. A thick and compact layer of soil prevents the access of developing slugs to the surface of the soil. Also, products containing iron phosphate should be used in the area.

The mucus secreted by the Spanish slugs protects it from predators. The natural enemies of the species include e.g. ground beetles, nematodes, hedgehogs, badgers, some birds (thrushes, mallards, ducks).

Spanish slug (spansk skogssnigel) – Arion vulgaris

No type specimen

Type specimen

No national museum collection specimen

National museum collection specimen