Slugs and Snails

ALL slugs and snails can carry the Rat Lung Worm parasite

Slugs and snails are a common garden pest that have a voracious appetite. They munch on plants leaving behind a gooey slime trail and damaged leaves. All slugs and snails are vectors of the Rat Lungworm parasite (Angiostrongylus cantonensis). Some can carry a higher parasite load than others, but you should treat all slugs and snails with caution. Handle with gloves or tools, never with your bare hands. Hammerhead flatworms and New Guinea flatworms are not slugs or snails despite their similar appearance, but they are invasive species that are also Rat Lungworm vectors.

Help us record the slugs, snails, and flatworms in Hawai’i! Take as clear of a picture as you can and attach it to the report.

If you are on the Big Island and need help IDing the slug/snail, email us the picture at biisc@hawaii.edu and if possible save the specimen in a sealed container. On other islands, take the animal to your local HDOA office or ISC.

Treating Slugs and Snails

There are multiple ways to manage the slug and snail population in your garden.

Slug bait
Slug jug
Make your yard less habitable, removing excess green waste

Common Slug and Snail Guide

Giant African Snail (Achatina fulica)

Full grown adults can get up to 8 inches long and 5 inches in diameter
Shells are brownish with darker brown lengthwise stripes
Seven to nine whorls, including a swollen long body whorl, and cover at least half the length of the snail.

adult african snail in grass — Adult Giant African Snail

immature african snail — Adult Giant African Snail

Semi-Slug (Parmarion martensi)

Full grown adults can get up to 2 inches
Various shades of mottled grey
Hump on the back
Piece of shell on the hump

adult and immature semi slugs. showing different sizes of semi slugs — Adult Semi-slug

Black Slug (Veronicella leydigi)

Black with a thin yellow stripe
Body appears leathery

black slug on root ball — Black Slug
Photo by: Scot Nelson

black slug feeding on produce — Black Slug
Photo by: Scot Nelson

Cuban Slug (Veronicella cubensis)

Various shades of brown
Two black/dark brown stripes along body, or no stripes. Stripes can be broken making them look spotty
Thin light colored line down the middle of the body
Adults can be around 2-3 inches long