This little terrestrial mollusk loves seedlings and young shoots, much to the gardener’s dismay. Leaving a shiny and viscous substance in its wake, the gastropod is easily spotted. Let’s follow in the footsteps of voracious slug!
Slugs of all sizes
Like the snail, the slug belongs to the group of gastropods, terrestrial molluscs that live in wetlands around the world. Among the most common species in Europe:
- The garden slug or horticultural slug (Arion hortensis) is the most common. 3 to 4.5 cm long, it has a bluish-gray or black tint;
- The gray slug or loach (Deroceras reticulatum) is small (3 to 5 cm long) but is among the most pest of all;
- Slug red (Arion rufus) is up to 15 cm long. Its color varies from dark red to black. It particularly attacks roots and tubers;
- The big slug (Limax cinereoniger) holds the record by showing 30 cm in length when extended.
Two pairs of tentacles for the slug
The head of the slug extends through four tentacles with very distinct functions. The upper pair (the longest) has the eyes while the other two have the tactile organs and olfactory. The mouth has two jaws with small teeth and a tongue (radula) covered withasperities very hard which facilitate the grinding of food. The body of the slug consists of a shield (or mantle) and an orifice respiratory on the side (pneumostoma). At the back of the shield, is the tail and under the ventral part, a foot that adheres to the ground.
The slug, a nocturnal animal
Living in a humid environment is a necessity vital for the slug. Made up of 85% water, it has no shell likely to protect it against evaporation. In order not to dry out (thus die), the gastropod has a permanent need to absorbwaterwhether through the skin, when drinking or eating. Thus, its daily activity revolves around the continuous search forhumidity. When night falls, the temperature drops and dew begins to form, the animal leaves its shelter in search of food. His slime (mucus) acts as lubricant when traveling. During the day, the slug hides in a hole or takes refuge in shaded areas, under piles of stones and wood.
The slug is not frost resistant
This animal at cold blood is very sensitive to ambient temperature and only activates within a specific range of thermo-hygrometric conditions (air humidity level). The optimum being around 18 °, a scorching summer accompanied by drought constitutes a real danger for the slug which must hide while waiting for the return of the rains. Without water, the mollusk cannot produce the mucus that allows it to move. In the same way, the gastropod sinks underground from 5 ° C, because the frost and the temperatures negative are fatal to him (he dies at -3 ° C).
The short life of the slug
Autumn and spring, seasons rainy, are the times chosen by the slugs to mate. Hermaphrodites, these gastropods reproduce by becoming male or female in turn. Spawning – which can count up to 200 eggs in packages of 10 to 50 – is placed in a safe place in an earthen hole or under their favorite refuge: a board, a tile, a stone, a pile of wood or any other place with high humidity. The snails will quickly become adults because the life expectancy of the animal isa year about.
The slug, the scourge of the garden and the vegetable patch
Slugs are able to devour the half of their weight in one night. They feed on the corpses of small animals, excrement and green waste, which they crush with their toothed tongues. But these greedy mainly attack crops with a preference for sowing, seedlings and young shoots. The damage is caused on a wide variety of plants: beets, cereals, potatoes, clover, alfalfa, carrots, radishes, turnips, cabbage, rapeseed, corn … The slug also consumes all kinds of flowers, buds, stems and same as fruits (strawberries, tomatoes).
Prevent the arrival of slugs in your garden
To prevent slugs from colonizing your exteriors, you can take a few actions to prevention :
- Dig in the fall and leave the ground uncovered in the winter to expose their eggs to the cold;
- Water the morning early rather than in the evening so as not to encourage the circulation of these nocturnal animals;
- Limit watering to plants that really need it because the water acts as a real magnet for these gastropods;
- Break the clods of earth which constitute shelters appreciated by these mollusks;
- Avoid planting near a stream, compost, or any other potential slug refuge.
Some methods of slug control
In addition to prevention actions, solutions natural exist to repel or eradicate slugs:
- Growing plants for effect repellent because slugs are bothered by strong odors. Examples: thyme, garlic, civet, mint, geranium, digitalis, fennel, onion, nasturtium, parsley, mint, marigold, borage…;
- Sprinkle at the base of the plants coffee grounds or baking soda which are also powerful repellents;
- Install physical barriers around the plants by digging a ditch to fill with ash, mulch, sawdust or wood chips. Sand strips are also effective;
- Arrange the evening in several places of the garden of artificial shelters like upturned earthenware pots, corrugated tiles, wet cardboard, black plastic sheeting or planks. The next day, all you have to do is pick up the slugs stuck on them;
- Fill small cups with beer to be buried by half. Attracted by the smell, the slugs will drown there;
- Finally, it is possible to apply iron phosphate in case of attack massive gastropods. This biodegradable product does not contain toxic substances for pets and organisms useful in the garden.