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Slugs & Snails

Non-native & native species in the Pacific Northwest

Updated Feb 22, 2023

Make a Positive Identification

Slug & Snail Damage

Slugs and snails are mollusks. They cause feeding damage to a wide range of plants and leave slime trails. They are mostly active at night. They also feed during the day when it is overcast, cool, and damp.
You’ll probably notice signs of damage to plants before you see actual slugs and snails.

Non-native Slugs & Snails

Non-native slugs and snails cause feeding damage on a variety of plants in gardens, landscapes, and farms in the Pacific Northwest.

Native Slugs & Snail

Many species of native slugs and snails, such as banana slugs, are a key part of the natural environment. Native slugs and snails are generally not garden pests and may be left alone.

Slug & Snail Damage & Signs

Species: Damage

Robin Rosetta, Oregon State University

Slugs and snails damage leaves by scraping or shredding them, and making ragged holes.

Species: Damage

Severe slug damage to brassica seedlings

svehlik, iStock

Slugs and snails may completely eat seedlings and the growing points of young plants. Severe damage may result in plant death or slow growth.

Species: Damage

Akchamczuk, iStock

Slugs and snails scrape holes in fruits such as tomatoes and strawberries.

Species: Damage

Signe Danler, Oregon State University

Some slugs spend more time underground and often feed on roots and tubers. They leave shallow or deep smooth-sided pits.

Species: Slime Trails

"evidence of a slime" by woodleywonderworks is licensed under CC BY 2.0.

Slugs and snails leave silvery slime trails on plants and other surfaces. They may also leave small sausage-shaped feces.

Non-Native Slugs & Snails

Species: Gray garden slugs

Cheryl Moorehead, Bugwood.org

Gray garden slugs (Deroceras reticulatum) are the most common garden pest slug in Oregon. They are also known as gray field slugs. They grow to 1.4–2 inches long.

Species: Threeband Garden Slug

Rebekah D. Wallace, University of Georgia, Bugwood.org

The threeband garden slug (Ambigolimax valentianus) is another common slug in gardens and public parks in Oregon. They have 2–3 dark-colored lines running the length of the body as shown in the photo.

Species: Giant garden slugs

"Spotted Leopard Slug (Limax maximus) DSC_0017" by NDomer73 is licensed under CC BY-NC-ND 2.0.

Giant garden slugs (Limax maximus) are widespread in Oregon. They have spots on their body as shown in the photo. They grow up to 4 inches long.

Species: Brown snails

Joseph Berger, Bugwood.org

Brown garden snails (Cornu aspersum) are the most common snail garden pest in Oregon. Their shell diameter ranges from 1–1.5 inches wide.

Species: European black or red slugs

Gary Bernon, USDA APHIS, Bugwood.org

European black or red slugs (Arion rufus) are widespread in Oregon. They have a reddish, orange, brown, or black color and grow to 2.75–4 inches long.

Species: Brown-banded Arion Slug

James Lindsey at Ecology of Commanster, CC BY-SA 2.5, via Wikimedia Commons

Brown-banded Arion slugs (Arion circumscriptus) have brown stripes on their back. They grow to less than 1.75 inches long.

Species: Glass snails

Michal Maňas, CC BY 4.0, via Wikimedia Commons

Glass snails (Oxychilus spp.) are present throughout Oregon. One species of glass snail (O. alliarus) emits a garlic odor when crushed. Their shell grows to 0.2–0.6 inches in diameter.

LOOK-ALIKES: NATIVE SLUGS & SNAILS

Species: Banana slugs

Thomas Schoch, CC BY-SA 2.5, via Wikimedia Commons

The Pacific banana slug (Ariolimax columbianus) is a common, native species in Western Oregon. Its color ranges from yellow, green, and gray to reddish brown, and even white. It also occurs with and without spots. Banana slugs grow from 7–10.2 inches long.

Tolerate if possible

Banana slugs live in forested areas. They don’t cause damage to garden plants. You may leave them alone.

Species: Pacific sideband snails

"Pacific Sideband (Monadenia fidelis)" by S0MEBODY 3LSE is licensed under CC BY 2.0.

Pacific sideband snails (Monadenia fidelis) often have distinct, dark stripes. Their shell grows from 0.7–1.5 inches in diameter.

Tolerate if possible

Pacific sideband snails live in forested areas. They don’t cause damage to garden plants. You may leave them alone.

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Slugs & Snails Benefits

Slugs and snails provide food for insects, birds, reptiles, amphibians, mammals, and other predators.

Slugs & Snails Risks

Slugs and snails damage plants and make them look tattered.
They can eat young plants to the ground and make crops such as strawberries unusable.
Slugs and snails have also been implicated in the spread of plant diseases and human pathogens.

Risk Card

Does it cause harm?

Adults & Children

None

Property

Low

Pets

None

Annoyance

Some

Environment

Low

Action Optional

Take Action?

Take action to protect vegetable crops, strawberries, and ornamental crops if you can’t tolerate the damage.

Do I need to take action?

You may ignore minor slug and snail damage. But damage may get worse as the population grows.
Slug and snail damage to small seedlings can be severe and lead to a complete loss. You may have to start over and suffer some economic loss.

What if I do nothing?
The damage may get worse as the population grows.

NEED HELP?

Consider a licensed pest control company. Learn How to Hire a Pest Control Company.
Your local Extension Specialist in Oregon and other states can suggest other methods.

Solutions for Slugs & Snails

For best results to control slugs and snails, use a combination of methods.

Monitoring & Timing

Look for slugs and snails at night with a flashlight and/or under planting containers, boards, rocks, and debris.
Control efforts in the fall and early spring will lower their numbers through the course of the growing season.

Non-chemical Methods

Remove slug and snail hiding places such as under planting containers, rocks, and boards.
Encourage slug and snail predators such as ground beetles, amphibians, and snakes. See Biological Pest Control Methods.
Hand-pick slugs and snails and drop them into a container with soapy water.
Use beer (or a mixture of flour, water, and yeast) and board traps to capture them.

Molluscicides (Mollusk-Killing Chemicals)

Molluscicides effectively reduce slug and snail populations. They don’t eliminate them.

Method	Does it work?	Is it safe?	Recommendation
A Attract Slug & Snail Predators	Somewhat effective	Low risk	Recommended
B Monitoring, Hand Picking & Trapping	Effective	Low risk	Recommended
C Molluscicides	Effective	Moderate risk	Use if Necessary
D If Using Molluscicides, Protect Yourself & Minimize Risks
E Prevent Slugs & Snails

Attract Slug & Snail Predators

Non-Chemical Method

"015_garter_snake_coiled_nwwd_odfw" by Oregon Department of Fish & Wildlife is licensed under CC BY-SA 2.0.

Attract Slug & Snail Predators

Recommended

Many vertebrates eat slugs and snails, including wildlife (birds, snakes, and frogs) and domestic animals (ducks). Spiders and beetles also prey on slugs and snails. Encourage those predators that fit with your gardening approach.

Does it work?	Somewhat effective Predators work to reduce slug and snail populations. They won’t eliminate slugs and snails. Use with other methods. Use preventive measures for best results.
How much effort?	Low effort Provide habitat for wildlife such as garter snakes (shown in photo) and soil-dwelling insects such as predatory ground beetles.
What's the risk?	Low risk
Possible risk of exposure or harm from chemicals	NONE

Predatory ground beetle eating a small slug

"The Golden ground beetle eating a slug on a countryside road" by gbohne is licensed under CC BY-SA 2.0.

Ground-dwelling spiders and invertebrates such as beetles (shown in photo), larvae of certain flies, centipedes, millipedes, and other snails eat slugs and snails and their eggs.

Domestic ducks eat slugs and snails. Be careful about allowing ducks in your garden. They will eat seeds and seedlings. They will also eat established plants if left too long in one location. Also, ducks pose a risk in terms of food safety for crops that grow low to the ground, such as lettuce and strawberries.

Monitoring, Hand Picking & Trapping

Non-Chemical Method

Signe Danler, Oregon State University

Monitoring, Hand Picking & Trapping

Recommended

Use these non-chemical slug methods to reduce slug and snail damage on and near plants you want to keep from being damaged.

Does it work?	Effective Monitoring, hand picking, and trapping methods work to reduce slug and snail populations. They won’t eliminate slugs and snails. Use with other methods. Use preventive measures for best results.
How much effort?	Moderate effort Monitor, hand pick, and set/clean traps repeatedly.
What's the risk?	Low risk
Possible risk of exposure or harm from chemicals	NONE

Worker monitoring for slugs at night with a flash light

"Hangar Garden: slug hunting by flashlight - 5" by yugenro is licensed under CC BY-SA 2.0.

Slug & Snail Monitoring

Begin monitoring for slugs in early spring. Continue through fall.
Water in the late afternoon to draw out snails and slugs. After dark, search them out using a flashlight.
Put out slug bait in late afternoon. Return early the next morning to check for dead slugs and snails.

beekeepx, iStock

Hand Picking

Hand-picking slugs and snails can be very effective if done regularly. Look in hiding places such as under rocks and foliage.
Wear rubber or latex gloves to pick them up, or use tongs. Seal the pests in a plastic bag and dispose of them in the trash. Or drop them in a bucket of soapy water (shown in photo).

"File:Tigerschnegel Eiablage.jpg" by Lokilech is licensed under CC BY-SA 3.0.

Search for Slug and Snail Eggs

Slugs and snails lay their eggs (shown in the photo) in the late summer and fall.
Search for slugs and snails and their eggs at this time of year. Dispose of them as previously described.
Removing egg clusters reduces the population of slugs and snails.

Slug and snail trap: yogurt container with hole cut in side, filled with beer

Signe Danler, Oregon State University

Trapping

Place flat boards or upside-down flower pots with one edge propped up around the garden. Slugs and snails will hide under them and may be collected.
Other traps use beer or a mixture of flour, water, and yeast in a deep yogurt container (or similar). Place the rim at ground level. Slugs and snails get trapped in the liquid in the container
Check traps and destroy pests regularly.

Molluscicides

Chemical Method: Use with caution

Weston Miller, Oregon State University

Molluscicides

Use if Necessary

Bait products with active ingredients iron phosphate, ferric sodium EDTA, and metaldehyde reduce slug and snail populations, but will not eliminate them. Metaldeyde can harm other organisms.

Does it work?	Effective Combine baits with other control efforts. Use preventive measures for best results.
How much effort?	Moderate effort Place baits near plants you want to protect. Re-apply as directed on the label.
What's the risk?	Moderate risk Molluscicides come with real risks. ALWAYS read the entire label front to back. Use a magnifying glass.
Possible risk of exposure or harm from chemicals	Using pesticides includes some amount of risk. The lowest risk comes without using pesticides. You may be exposed to a pesticide if you: Get it on your skin Breathe it in Eat or smoke afterward without washing hands Touch or eat plants that are wet with spray (you, pets, or children) Bring it inside on your shoes or clothes Follow directions closely to reduce risk.

Molluscicides contain active ingredients iron phosphate, ferric sodium EDTA, and metaldehyde. Determine which ingredient is right for your situation.

Example product label with active ingredient iron phosphate

Weston Miller, Oregon State University

Iron Phosphate (Approved for Organic Farming)

The white box on the example product label highlights the active ingredient iron phosphate.
Iron phosphate causes snails and slugs to stop feeding and die within 3 to 6 days.
Iron phosphate remains active for up to 2 weeks, even after it gets wet.
It’s considered safe to use around pets, humans, fish, birds, beneficial insects, and mammals. It may be used around food crops and ornamental plants.

Weston Miller, Oregon State University

Ferric Sodium EDTA

The white box on the example product label highlights active ingredient ferric sodium. The label states “Attracts and kills slugs and snails."
Ferric sodium EDTA is a newer active ingredient that works similar to iron phosphate.
Products with ferric sodium EDTA aren’t approved for use in organic farming.

Metaldehyde

The white box on this example product label highlights active ingredient metaldehyde.
Metaldehyde destroys the mucus-producing system so snails and slugs dehydrate from exposure to the sun.
If it rains soon after application, this may not work.
Metaldehyde is not recommended for use around edible vegetables.

Metaldehyde is toxic to people, dogs, cats, birds, and fish. Read and follow the label instructions carefully.

MolluSCICIDE Application Tips

Placement of baits

Scatter baits on the soil near the base of plants that are prone to slug and snail damage.
Apply the bait close to slug and snail hiding places such as raised bed sides, rock walls, pavers, and fences.
Apply repeatedly in the same areas. Check the product label to ensure it can be reapplied in the same area.
Irrigate before baiting in home gardens in order to bring more slugs to the surface or out of hiding during the night.

Timing of baits

Apply baits in the late afternoon or evening. This takes advantage of the pests’ nighttime feeding habits.
The best time to treat the whole garden for long-term control is in the autumn. Then, there will be fewer adult slugs and snails to lay their eggs.
Baits are most effective in moist weather and moderate temperatures. Slugs are less active in hot, cold, dry, or extremely wet conditions.

Limitations

Molluscicide baits will not be very effective unless you also remove shelter and moisture. Slugs that survive poisoning by baits tend to avoid the baits in the future.

Alternative Chemical Options

Alternative chemical options include certain botanical products such as limonene and repellent botanical products such as cinnamon oil.

If Using Molluscicides, Protect Yourself & Minimize Risks

Chemical Method: Use with Caution

ChristopherBernard, iStock

Metaldehyde baits are a leading cause of accidental poisoning of dogs in the Pacific Northwest.

Why Is It important to Read Molluscicide Labels?

They have detailed information on how to use the product correctly and legally.
They contain information on potential hazards of the product.
They provide instructions you should follow for poisonings and spills.
Following label instructions helps you to minimize the risks and maximize the benefits.

Key Safety Tips

Read the entire label front to back.
Follow the instructions.
Review the instructions even for brands you know.
Only apply the product where the label says it may be applied.
Keep all molluscicides in their original container.

The Label is the Law

ALWAYS read the label before using molluscicide products. The label is a legal document that provides information on how to safely use the molluscicide. This helps avoid harm to human health and the environment. Using a molluscicide in off-label ways is illegal. It can result in legal enforcement actions.

READ THE LABEL & Follow Instructions
It has instructions to protect you and the environment.

Labels are different for every product and they often change over time.
Use a magnifying glass.
Pay attention to CAUTION, WARNING, and DANGER statements.
Pay attention to the PRECAUTIONARY STATEMENTS.
The law states you must read and follow molluscicide instructions.

Protect Yourself
Eye, skin, & lung irritants

Wear gloves, safety glasses, a long-sleeve shirt, pants, socks, and shoes.
Avoid contact with eyes, skin, or clothing.
Wash hands after mixing or applying, and before eating or smoking.
Never spray directly overhead. Pay attention to wind conditions.

Protect Children, Pets, Domestic Animals & Wildlife
Children, pets, and wildlife are at risk if they touch or consume metaldehyde-based slug control products.

Keep molluscicides out of reach from children and pets at all times.
Dogs, cats, and wildlife are also attracted to and harmed by metaldehyde.
Apply slug and snail baits under a piece of plywood, or something similar, to keep pets away from the pellets.

Storage & Disposal

Store out of the reach of children and pets.
Store in a cool and dry place.
Never pour down any drain.
If you mix too much, apply it rather than storing it.
Don’t put pesticide containers in the trash unless instructed by the label.
Take unused molluscicides to a hazardous waste facility.

Call 1-800-CLEANUP (1-800-253-2687) to find out where to dispose of pesticides.

For the Portland metro region in Oregon, contact Metro’s Recycling Information. Call 503-234-3000, email or visit Metro’s website

More about:

About Using Pesticides on School Grounds in Oregon

If using pesticides on school grounds, there are special rules in Oregon. See School Integrated Pest Management (Oregon Department of Agriculture).