In the last several years, a 

newly introduced species of 

slug, Veronicella cubensis, has 

multiplied on the island of Rota 

and is now a serious pest of local 

crops and threatens other areas. 

The effect on the island’s 

natural environment and on 

ecotourism is potentially very 

serious. Residents should take 

precautions not to move slugs to 

new areas of the United States’ 

Commonwealth of the Northern 

Mariana Islands, where they may 

cause further damage. The slugs 

hitchhike on unwashed plants 

and produce that are carried to 

other islands.

Description

The Cuban slug varies in 

appearance and can sometimes 

be confused with another 

introduced, but less serious, 

slug species—the bean slug 

(Sarasinula plebeia). The 

coloration of the Cuban or bean 

slug may show varying shades 

Pest Alert Plant Protection and Quarantine

March 2006

Stop the Spread of the Cuban Slug!

of brown, sometimes with two 

black or dark-brown bands on 

the back, which may appear as 

spots. A thin, lighter-colored 

stripe may appear on the midline 

running lengthwise. Slugs may 

also be albino, or white in color. 

They can be smooth or granular 

in appearance. The only way 

to positively distinguish the 

Cuban slug from the bean slug is 

laboratory dissection performed 

by an expert.

Agricultural Threat

Both the juvenile and mature 

forms of the Cuban slug can 

cause significant feeding 

damage to plants. This slug 

feeds on many different native, 

ornamental, and agricultural 

plants. These include melon, 

pumpkin, pepper, eggplant, 

cabbage, cassava, taro, sweet 

potato, yam, papaya, banana, 

star fruit, mango, noni, citrus, 

and coffee.

Public Health Warning

Like many other species of 

slugs and snails, the Cuban slug 

can carry a tiny organism that 

causes potentially lethal disease 

in humans. The organism 

is a parasitic nematode, 

Angiostrongylus cantonensis, 

also called the rat lungworm. 

People get sick by eating 

uncooked or undercooked slugs 

or snails, or by eating lettuce 

or other uncooked greens that 

contain small slugs that may 

not be noticed during food 

preparation. Even the slime trail 

of slugs and snails can contain 

the nematode that causes 

disease. For more information 

about this disease and how to 

prevent it, contact your local 

health department or visit the 

Web site of the Centers for 

Disease Control and Prevention 

at <http://www.dpd.cdc.gov/

dpdx/HTML/Angiostrongyliasis.

htm>.

Brown and albino 

Cuban slugs in 

the extended 

state.

A Cuban slug in the contracted state.
Don’t Spread the Slug!

Before taking vegetables or 

plants to other islands, make 

sure all soil has been removed 

by washing, and inspect the 

material carefully to make certain 

there are no attached slugs. Be 

especially careful with live plants 

that have roots or lots of leaves 

because these can become 

hiding places for slug eggs or 

small (immature) slugs.

Control Measures

Planting materials known to 

be free of the pest is the best 

protection for areas not yet 

infested with the Cuban slug. In 

agricultural areas where slugs are 

already present, pelletized food 

bait that contains metaldehyde 

as the active ingredient is 

usually the most effective type 

of chemical control. Initially, it 

may be necessary to apply bait 

pellets throughout the growing 

area. Subsequent applications 

can be targeted in areas where 

Several immature Cuban slugs feed on woody biomass (left) and on fallen star fruit. 

This publication reports research 

involving pesticides. All uses of 

pesticides must be registered by 

appropriate State and/or Federal 

agencies before they can be 

recommended.

CAUTION: Pesticides can be injurious 

to humans, domestic animals, desirable 

plants, and fish or other wildlife—if they 

are not handled or applied properly. Use 

all pesticides selectively and carefully. 

Follow recommended practices for 

the disposal of surplus pesticides and 

pesticide containers.

United States 

Department of Agriculture

Animal and Plant Health 

Inspection Service

Program Aid No. 1834

Issued March 2006

slugs hide during the day, such 

as field edges, rocky areas, or in 

or under piles of debris. Federal 

law requires the person applying 

pesticides to follow the directions 

and precautions listed on the 

pesticide label.

Note: Metaldehyde bait, if eaten, 

is very poisonous to people 

and domestic animals. In some 

cases, it may be impossible to 

place the baits in areas where 

slugs, but not domestic animals, 

are likely to find and consume 

the baits.

The U.S. Department of 

Agriculture is an equal 

opportunity provider and 

employer.

Photo credits: All photos in 

this Pest Alert were taken by 

David Robinson, APHIS–Plant 

Protection and Quarantine’s 

national malacologist.