Snails belong to the class Gastropoda. They prefer an undisturbed habitat with adequate moisture and good food supply. The snail body is protected by a hard shell, usually marked with spirals. Most land snails are nocturnal, but following a rain may come out of their hiding places during the day. They move with a gliding motion by means of a long flat muscular organ called a foot. Mucus, constantly secreted by glands in the foot, facilitates movement and leaves a silverlike slimy trail. The reproductive organs of both sexes occur in the same individuals and each is capable of self-fertilization, although cross fertilization is normal. Adults deposit eggs.
In the United States, Capinera (2001) reports it in California and along the west coast north to British Columbia, Canada, in most southeastern states and along the east coast north to New Jersey. However, it has not developed the serious pest status found in California. Although occasionally intercepted on plant shipments to Florida, it has not become established in this state.
Description
The shell is large, globose, rather thin, imperforate or nearly so, moderately glossy, sculptured with fine wrinkles. The shell may either yellow or horn-colored with chestnut brown spiral bands which are interrupted by yellow flecks or streaks. The aperture is roundly lunate to ovate-lunate, with the lip turned back. Adult shells (four to five whorls) measure 28 to 32 mm in diameter (Burch, 1960).
Frequency of oviposition is subject to temperature, humidity, and soil conditions. Low temperature and low humidity inhibit the activity of the snail, and dry soil is unsuitable for the preparation of a nest. During warm damp weather, ovipositions may be as frequent as once a month. Low humidity and cold temperatures greatly inhibit the activity of the snails during the fall and winter months. If each individual is capable of laying eggs once every six weeks from February to October, then approximately five ovipositions are made each year and 430 eggs laid (Basinger 1931).
During the summer months, the eggs hatch in about two weeks. The shells of hatchlings are fragile and translucent. Maturity requires about two years in southern California. In South Africa the snails take about 10 months to become mature, producing one generation a year (Gunn, 1924). When dry conditions prevail, the snail may seal itself to various objects or close the shell opening with a parchmentlike epiphragm. With the advent of humid conditions, the snail again becomes active.
Brown garden snails attain a diameter of 16 to 20 mm within one year, but 26 to 33 mm by the second year. These snails are nocturnal and feed on organic matter in the soil, bark from trees and especially on vegetation. Nearly anything growing in a vegetable or flower garden can be consumed. They normally feed only within the temperature range of 5 to 21°C (Capinera 2001).
Gunn (1924) listed 49 plants as hosts in South Africa:
Vegetables: cabbage, carrot, cauliflower, celery, bean, beet, brussels sprouts, lettuce, mangel, onion, peas, radish, tomato, and turnips.
Cereals: barley, oats, and wheat.
Flowers: alyssum, antirrhinum, aster, balsam, carnation, candytuft, chrysanthemum, dianthus, dahlia, delphinium, hollyhock, larkspur, lilies, marguerite, mignonette, nasturtium, pansy, pentstemon, petunia, phlox, stock, sweet-pea, verbena, and zinnia.
Trees: apple, apricot, citrus, peach, and plum. Shrubs: hibiscus, magnolia, and rose.
Habitat reduction will aid in control. Remove anything snails may hide under: boards, bags, brush and debris. During the night, place a board on the ground near damaged plants. Elevate the board with four stones placed under the corners. The snails will take shelter under the board in the morning and can be removed and then destroyed then by dropping into a jar filled with water and a little rubbing alcohol. Some birds, especially ducks, will feed on these snails (Garofalo 2001).
Barriers of diatomaceous earth, sand or ashes provide only temporary control. With a beer trap the goal is to trap and drown snails and slugs in a shallow dish with beer placed slightly below grade so that the lip of the dish is even with the soil. However, this does not provide reliable control (Bradley 1999).
Florida Insect Management Guide for landscape plants
Florida Insect Management Guide for vegetables
Florida Insect Management Guide for citrus
Florida Insect Management Guide for fruit
Remarks
The brown garden snail has been eradicated from at least two locations in Florida since 1963 by the Division of Plant Industry. Most infestations are believed to be introduced on shipments of container-grown plants from California.
Due to the brown garden snail, various states in the United States have quarantine restrictions concerning plant materials brought in from other states. States with quarantine regulations include Arizona, California, Louisiana, Mississippi, Oregon, South Carolina, Texas and Washington. However, other states may also have quarantines. Check with each state's Department of Agriculture to be sure before shipping or taking potentially infested materials to other states.
Selected References
Author: G.W. Dekle, Florida Department of Agriculture and Consumer Services, Division of Plant Industry; and T.R. Fasulo, University of Florida.
Originally published as DPI Entomology Circular 83. Updated for this publication.
Photographs: Bill Frank, Jacksonville Shell Club; Paul M. Choate, University of Florida; and Division of Plant Industry
Project Coordinator: Thomas R. Fasulo, University of Florida
Publication Number: EENY-240
Publication Date: October 2001. Latest revision: June 2011.
Copyright 2001-2011 University of Florida
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adults
adult extended
color shades
yellow coloring
size comparison
snails on citrus tree