Snails and Slugs in the Low Desert

DESCRIPTION:

• Brown Garden Snail ( Helix aspersa) - about one inch in diameter when full grown, rounded brown and beige mottled shell. Lays up to 80 white, spherical eggs at a time into a hole in the topsoil. They can lay eggs as many as six times a year. During cold weather they hybernate and during hot dry weather snails are able to seal themselves off in their shell. NOTE: even though the weather may be hot and dry, your garden may be cool and moist thanks to your irrigation system.
• Decollate snail (Rumina decollata) - elongated spiraling shell (Note: This species will prey upon the Brown Garden Snail and is sold as a beneficial predator, however, if there are no garden snails to feed upon it can become a serious pest of emerging seedlings and bedding plants.)
• Gray Garden Slug (Agriolimax reticulatus )- similar in form and biology to a snail without a shell.

DAMAGE:

Slugs and snails are active at night feeding on plants. They tend to feed on seedlings, tender, low-growing leafy vegetables, and ripening fruit. They chew smooth edged, irregular holes. Look for a "slime trail" as evidence of their presence.

MANAGEMENT:

• Modify Environment: Snails and slugs often build up in moist soil condition - check to be sure you are not over watering. Irrigate early in the day to ensure that surfaces are dry by evening. Remove hiding places.
• Use Barriers: Use copper flashing or six inch vertical copper screen burried several inches in the ground around planting beds to exclude snails and slugs. Copper foil can be wrapped around the trunk of trees to prevent snails from climbing.
• Hand Pick: Slugs and snails are active at night and hide under boards and debris during the day. Set out boards and remove snails or slugs that collect there during the day. Go out at night and collect and dispose of snails and slugs.
• Baits: Commercial molluscicidal baits are available, be sure to keep well away from pets and children.

• Barriers of diatomaceous earth, sand or ashes provide only temporary control.
• Beer Trap: 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. This does not provide reliable control.