Brown garden snail (Cantareus aspersa)

Synonyms: Cornu aspersum, Helix aspersa, Cryptomphalus aspersus, Cantareus aspersus

Common Names: European brown garden snail, common garden snail, garden snail, escargot

Description:

Brown garden snail (Cantareus aspersa) is a large land snail from the Mediterranean region and western Europe, and one of the most damaging garden and farm snails in the world [1][2]. It was brought to California in the 1850s to be raised for escargot and has spread since, partly on nursery plants [1]. MISIN tracks it because it feeds on garden plants, ornamentals, and crops such as citrus, and it is a quarantine-significant pest that travels on shipped plants [1][3].

Identification:

The brown garden snail is a large, familiar-looking snail with a rounded, globe-shaped shell about 1 to 1? inches (25?40 mm) across and four to five whorls [1]. The shell is yellow, tan, or horn-colored with chestnut-brown spiral bands broken up by yellow flecks, and its surface is finely wrinkled rather than smooth [1]. The body is brownish-gray, and like all land snails it leaves a silvery slime trail as it moves [1]. It is the classic "garden snail" many people already picture [1].

Brown garden snails are easiest to find at night and during damp or rainy weather, when they come out to feed on plants; in dry or cold spells they seal themselves up and hide under boards, pots, debris, and dense ground cover [1]. Look for the snails themselves, their silvery trails, and chewed leaves and fruit [1].

At-a-glance cues:

1. Large, rounded shell about 1?1? inches across with 4?5 whorls [1]
2. Yellow-to-tan shell with chestnut-brown spiral bands and yellow flecks, finely wrinkled surface [1]
3. Brownish-gray body that leaves a silvery slime trail [1]
4. Active at night and in damp weather; hides under cover by day [1]

Habitat:

Brown garden snails live in moist, sheltered places with plenty to eat. They are most at home in gardens, yards, orchards, citrus groves, parks, and other watered, shaded spots, often in loamy soil under tree canopy [1]. They need moisture and cover, so they thrive in irrigated landscapes and hide by day under boards, pots, mulch, and dense plants [1].

The snail is native to the Mediterranean region and western Europe [1][2]. It is now established on most continents, including much of North America, spread both deliberately as a food snail and accidentally on nursery plants and in soil [1][2]. It is most damaging in mild, moist climates such as coastal California, and in colder regions it is mainly a watch species moved with horticulture [1].

Reproduction:

Brown garden snails are spread by people more than on their own. They and their eggs ride along in the soil of potted plants, on nursery stock, and in moved garden materials, and the species has also been carried around the world on purpose as a food snail [1][2]. Each snail is a hermaphrodite ? it has both male and female parts ? but two snails still mate before laying eggs [1].

They are prolific breeders: a single snail can lay roughly 30 to 120 eggs in a clutch and produce several clutches a year ? on the order of a few hundred eggs annually ? and they take about two years to mature and can live several years [1]. Because of this steady output, a few snails can build into a damaging population. For control, the key is to remove snails and their hiding places before numbers climb, and to inspect incoming plants and soil so new snails are not introduced (see Management) [1].

Impact and Damage:

Brown garden snails are not dangerous to handle ? they are the same species raised as escargot ? but they are a serious pest of plants. In a yard or garden they chew ragged holes in the leaves, flowers, and fruit of vegetables, ornamentals, and seedlings, often feeding at night so the damage appears before the culprit is seen [1]. They can be especially destructive to tender new growth and to ripening fruit [1].

On farms the damage is costly. The brown garden snail is a major agricultural pest of citrus and other crops, where it eats leaves, bark, and fruit and contaminates produce, and it is treated as a quarantine-significant pest so that shipments of nursery plants and produce are inspected and restricted to keep it from spreading [1][3]. Its effects on native snails and natural areas are less well documented, but as an abundant introduced snail it can compete with native species for food and shelter [2].

Similar species:

A few other land snails can be mistaken for the brown garden snail.

White garden snail (Theba pisana) is another introduced pest snail, but it is smaller and chalky white to cream with thin brown bands, rather than the larger, wrinkled, yellow-and-brown shell of the brown garden snail.

Grove snail (Cepaea nemoralis) is a smaller banded snail with a glossy yellow, pink, or brown shell and a dark lip around the opening, lacking the brown garden snail's large size and finely wrinkled surface.

Native land snails (various species) are generally smaller and more plainly colored, and an expert can separate them by shell details. A large, globe-shaped, brown-banded snail common in a garden or orchard is far more likely to be the introduced brown garden snail.

Monitoring and rapid response:

Signs to watch for:

1. Large, rounded, yellow-and-brown banded snails in gardens, beds, and orchards, active at night and in damp weather [1]
2. Silvery slime trails and ragged chewed holes in leaves, flowers, and fruit [1]
3. Snails clustered under boards, pots, mulch, and dense ground cover during the day [1]

What you can do:

1. Hand-pick snails at night or after rain when they are active, and drop them in soapy water or seal them in a bag for the trash [1].
2. Remove daytime hiding places ? boards, debris, and dense ground cover ? and avoid overwatering, since the snails need moisture and shelter [1].
3. Use physical barriers such as copper tape around raised beds or tree trunks to keep snails off plants [1].
4. Inspect new potted plants, gravel, and garden soil for snails and their eggs before bringing them home, and do not move infested plants or soil [1].
5. Report sightings (below), and growers or crews moving plants should follow clean-stock practices and coordinate with the state agriculture program, since this is a quarantine-significant pest [1][3].

When to call a professional:

1. Heavy infestations, or snails damaging an orchard, nursery, or crop ? contact your local cooperative extension office or state agriculture program for current guidance [1][3].
2. For chemical control options, contact a licensed applicator or your local cooperative extension office.

Report sightings to MISIN. Help track this species' spread by submitting observations through the MISIN web site or the MISIN mobile app (Android, iOS, Windows, and macOS). Photos at multiple angles paired with a precise GPS location are the most valuable data for confirming new occurrences and triggering rapid-response review.

Credits:

1. University of Florida IFAS, Featured Creatures. Brown Garden Snail, Cornu aspersum (Muller). ask.ifas.ufl.edu
2. CABI. Cornu aspersum (common garden snail) ? Invasive Species Compendium. cabidigitallibrary.org
3. Canadian Food Inspection Agency. European Brown Garden Snail (Cornu aspersum) ? Fact Sheet. inspection.canada.ca

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