Look closely before destroying: among slugs are both beneficial and protected species

Homeowners and gardeners in Lithuania are grappling with an increasing population of slugs, especially after rainy weather brings them onto paths and sidewalks. The invasive Spanish slug (Arion vulgaris) is proving particularly troublesome, damaging garden plants, seedlings, and vegetable harvests. Various methods are being employed to combat the problem, from manual collection and traps to salt, special granules, and even vinegar solutions.

However, the Dzūkija-Suvalkija Protected Areas Directorate is cautioning against indiscriminate eradication. They stress that not all slugs are pests, and some native species are beneficial or even protected. It is crucial to correctly identify invasive slugs before resorting to control measures. The Spanish slug, first detected in Lithuania in 2008, has spread rapidly and is now found across much of the country.

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not all slugs are our enemies. Therefore, control measures should be taken responsibly – first, it is necessary to make sure that it is an invasive slug, and not a species that does more good than harm to nature.

Adult Spanish slugs typically measure between 7 to 15 centimeters and can range in color from orange and brownish to brick red, though darker individuals exist. They are often a uniform color, with a distinct breathing pore on the right side of their mantle. These slugs favor damp, overgrown areas like gardens and compost heaps, where they feed on vegetables, ornamental plants, fruits, and young seedlings, causing significant damage. Their rapid reproduction can lead to large infestations, posing a threat not only to cultivated plants but also to native slug species and overall biodiversity.

Despite their destructive nature, the Directorate advises against judging slugs solely by size or color. Larger native slugs, such as the great grey slug (Limax maximus) and the black keel slug (Limax cinereoniger), do not harm gardens and contribute to natural decomposition processes. These slugs are characterized by their grey, mottled bodies with a pattern resembling leopard spots, although this can be indistinct when the slug is contracted, leading to potential confusion with other species. The great grey slug primarily feeds on decaying organic matter.

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not all large slugs are pests – among them are both beneficial and even protected species.