Slugs and snails are soft-bodied wormlike animals, members of the mollusk zoological group. Snails have coiled shells. Slugs have no shells.
Slugs and snails can be as small as 1/8 inch to as large as 8 inches long. They can be gray, tan, green, black, yellow or spotted. The presence of snails and slugs is betrayed by the secretion of a slimy mucus on which they glide along leaving a shiny trail.
Slugs and snails feed at night and on overcast days. They go under cover when the sun shines. Slugs and some snails can burrow into the soil while other types of snails hide in debris or on plants. If conditions are too dry, a snail can seal itself in its shell and remain dormant for up to 4 years.
Every slug and snail has both male and female sex organs so any individual can lay clusters of tiny gelatinous eggs in the soil. Some can fertilize their own eggs. Adults lay eggs in moist soil or under rocks or garden debris. The eggs hatch in 2 to 4 weeks and young grow five months to two years before reaching maturity.
Snails and slugs and their eggs can overwinter. The adults emerge in early spring and are active until the summer weather gets dry and hot—then they burrow or hide where it is cool. They emerge again in the fall when the weather turns cool.
Target Plants: Almost all plants, especially young seedlings, leafy crops, beans, tomato fruits, strawberry fruits.
Feeding Habits and Damage: Snails and slugs rasp large ragged holes in foliage, stems, fruits, and bulbs. They can eat seedlings whole. They eat tender plants and shrubs.
Organic Controls: Handpick slugs and snails when they emerge in the evening. Place shallow saucers of stale beer in the garden to attract and drown slugs and snails. Dust with diatomaceous earth around target plants—slugs and snails will be injured and die after crossing diatomaceous earth. Iron phosphate is an organic material that is toxic to slugs and snails. (Avoid baits that contain metaldehyde which is toxic to people and animals.)
Organic Control Calendar: Here is what you can do seasonally to control slugs and snails:
- Before planting: Remove any surface mulch, loose wood, or debris under which snails and slugs can harbor during the day. Put drip irrigation in place or plan to handwater to keep soil mostly dry.
- At planting time: Place repellent barriers around planting beds—diatomaceous earth, crushed eggshells, pine needles, wood ash, dry sand, lime. Set a copper barrier in place around planting beds.
- While crops develop: Overlaid flower pots grape fruit halves and boards laid on the ground make good traps. Wrap copper strips around the stems of plants and use copper flashing at the edge of garden beds. Attract slugs and snails with raw cabbage leaves then collect and destroy in early morning. Trap in shallow pans of beer buried to the lip of container in soil. Protect seedlings with wide bands of wood ashes or diatomaceous earth.
- After harvest: Clean the garden of all garden debris under which snails and slugs can harbor during the winter.
Natural Predators: Animal predators include downy woodpeckers, robins and other garden birds. Other animal predators are garter snakes, salamanders, toads, turtles, chickens and ducks. Insect predators include black rove beetles, centipedes, firefly larvae, ground beetles, and soldier beetles.
Scientific Name: Phyllum: Mollusca.