Ornamental

SLUGS & SNAILS

James R. Baker, Extension Entomologist, Emeritus

CAUTION: This information was developed for North Carolina and may not apply to other areas.

[General Information] [Biology] [Control] [Other Resources

SLUGS, Spotted garden slug, Limax maximus Linnaeus, and other species; Limacidae; STYLOMMATOPHORA

General Information

slug photo snail photoAdult slugs are soft, slimy, slender animals more closely related to clams and octopi than insects. Slugs have stalked eyes and two small feelers. Some species grow to 3 or more inches long. Slugs have various spots and stripes. Slug eggs are oval and up to 3 mm long. They are clear or cream or yellow and are usually laid in masses sometimes in a gelatinlike substance. Snails will have a similar habit, but carry a shell.

Biology

Slugs are found throughout the United States and Europe. Slugs feed on the leaves and flowers of many ornamental, vegetable and field crops. They are most damaging to tender, young crops in spring. Slug damage on foliage usually appears between the veins and on leaf margins. Small slugs rasp away the leaf or petal surface. Medium slugs often eat holes. Large slugs consume whole leaves, petals and sometimes entire plants if the plants are small, A silvery slime trail is left behind. Greenhouse slugs tunnel through soil and feed on roots. Slugs are active at night and during cloudy, warm weather. During bright warm weather, slugs usually hide under boards, stones, debris or tunnel into the soil. At night, especially in warm, humid weather, slugs feed on decaying organic matter and succulent plants. Their mouthparts resemble tiny rasps, and they rasp away plant tissue and suck up the residue. Slugs feed on many
slug with slimekinds of plants but they tend to stick with one plant, often consuming it entirely before moving on.

Mature slugs lay eggs anytime throughout the growing season. Eggs are laid in batches of 20, 30 or more under boards, pots or in the soil. Eggs are resistant to drying out and their development may be delayed until sufficient moisture is available. Young slugs develop relatively slowly. Slugs may take up to a year to mature.

Control

Sanitation - Slug populations can be reduced by eliminating their breeding and hiding places Remove rotting boards, logs, pots and other debris from the area. Compost or destroy plant refuse and properly stack or store flats, boxes, etc., which provide shelter for slugs. Trim tall grass and weeds along fences and ditches in the vicinity of susceptible crops.

Traps - In small plant beds and gardens, place boards or other flat objects on the soil. These traps should be at least 6 by 6 in. Each morning remove the slugs from beneath the traps and destroy them. For snails in water gardens, float lettuce or cabbage leaves on the water surface over night. Remove the leaves with any attached snails every morning until no more are found.

Pesticides - BEFORE USING A PESTICIDE IN A VEGETABLE GARDEN, CHECK TO BE SURE IT IS LABELLED FOR THAT USE. In some instances, the molluscicide (slug-killing agent) should be used only at the ends of the garden or in walkways. For best control, apply the molluscicide on a warm, clear night under boards or traps. Two or more treatments at 5 to 7 day intervals may be necessary to obtain adequate control. In the list below are pesticide formulations labeled for slug control in North Carolina. Because there is considerable variation in the percentages of pesticides included in various brands, it would pay to shop comparatively.
Do not use Mesurol or Metaldehyde products around pets.  Iron phosphate products are labeled safe around pets, but efficacy reports have been variable, at this time.

Some people have been known to kill slugs with table salt. Note that table salt is not labeled for this use and excessive amounts could affect soils.


BAITS
carbaryl (Sevin)
metaldehyde 2 to 3.3%
carbaryl (Sevin) 4 to 5% + metaldehyde 1 to 3.25%
iron phosphate (Bayer Advanced Snail & Slug Killer Bait, Sluggo)
SPRAYS and AEROSOLS
carbaryl (Sevin) 5% + malathion 12.5%
metaldehyde 4% liquid ready to use
metaldehyde 20% emulsifiable concentrate
methiocarb (PT 1700 Methiocarb) 1% aerosol
methiocarb (Mesurol) 75% wettable powder

Many of these formulations are suitable for home use.

Useful Links:
Jim Baker's Key to Common and Potential Slug and Snail Pests of Flowers and Foliage Plants in NC
Robin Rosetta's Oregon State University Slug Page
Identification Guide to Land Snails and Slugs of Western Washington
Key to Slugs of British Columbia


Recommendations for the use of chemicals are included in this publication as a convenience to the reader. The use of brand names and any mention or listing of commercial products or services in this publication does not imply endorsement by the North Carolina Cooperative Extension Service nor discrimination against similar products or services not mentioned. Individuals who use chemicals are responsible for ensuring that the intended use complies with current regulations and conforms to the product label. Be sure to obtain current information about usage and examine a current product label before applying any chemical. For assistance, contact an agent of the North Carolina Cooperative Extension Service in your county.


Other Resources

© 2001 NC Cooperative Extension Service

Prepared by: James R. Baker Extension Entomologist Emeritus. All illustration use by permission only.
ENT/ort-22

July 1994 (Revised) April 24, 1998

Web page last reviewed January, 2011 by the webperson.