Insect and Related Pests of Foliage Plants
Key to Slugs and Snails
With external shell (Fig.127) .......Snails, 2
Without external shell (Fig. 128) .......... Slugs, 5
Shell an elongate spire that is often broken off (Fig. 129); These snails mainly feed on other snails; they are not considered a pest ..... Rumina sp.
Shell not an elongate spire .......3.
Shell a flattened disc spiraling toward the center (Fig. 130); these snails mainly feed on other snails, they are not considered a pest,......Oxychilus sp.
Shell oval, with a large teardrop-shaped aperture which is approximately two-thirds the total shell length (these snails feed on algae and soft vegetable matter, they are not considered a pest, Fig. 131) ........Succinia sp.
Shell globular, with the aperture approximately the shell diameter (Fig. 132) ..... Brown garden snail.
Breathing pore located in anterior half of mantle; back never keeled; posterior end rounded when viewed from above (Fig. 133); these slugs can do considerable damage, ...... Arion sp.
Breathing pore located in posterior half of mantle; back keeled at least at posterior end which is pointed in dorsal view ....... 6
Back strongly keeled from the mantle to tip of tail; mantle grainy with center part bound by a groove (Fig.134); usually burrows in the soil and feeds on roots, ..... Greenhouse slug.
Back keeled only near posterior end; mantle wrinkled in concentric circles, without a groove .....7.
Mantle and body with black spots; large slug (up to 150 mm) (Fig. 135).....Spotted garden slug.
Mantle and back without well defined spots ........ 8.
Mantle and back with well defined, dark stripes; breathing pore not surrounded by a pale ring (Fig.136); exudes watery slime when irritated ......Lehmannia slug
Mantle and back without well defined stripes; breathing pore surrounded by a pale ring....9
Medium sized slug (up to 50 mm) (Fig. 137); gray to reddish brown; exudes milky adhesive slime when irritated ..... Gray garden slug.
Relatively small slug (up to 25 mm) (Fig. 138) light gray to blackish brown; exudes clear, watery mucus when irritated ..... Brown slug.
