Slugs can cause a lot of damage in the garden, especially if the infestation gets out of hand. Fortunately, slugs can be controlled quite easily in a variety of ways. Anyone who shares a garden with slugs must take drastic measures.
How do I fight slugs?
If slugs become a nuisance, it indicates a disturbed balance in the garden. The dreaded visitors reproduce in large numbers when there are no natural enemies and the living conditions are optimal for them. There are a whole range of remedies against slugs, but there is no 100% guarantee that they will permanently get rid of slugs. If you want to get rid of snails, you need to make your garden snail-unfriendly.
Slugs feel at home here:
- mulched beds with even moisture
- shady areas where there are no temperature fluctuations
- Microhabitats with warm, humid weather such as compost
Defense through bait and trap
Nudibranchs can be caught with bait and collected
There are ways you can keep the molluscs away from valuable crops. A mixture of moistened dry dog or cat food and wheat bran provides a treat for slugs. Offer the bait in recycled cups that you bury in the ground. This means you can then easily collect and dispose of the snails.
How to build a beer trap:
- Cut square corners two centimeters apart from the top edge of a yogurt cup
- Fill the cup with beer up to one centimeter below the cutouts
- Close with lid to avoid watering down by rain
- Dig the cup into the ground so that the edge protrudes by one or two centimeters
Remove and empty the container regularly to ensure the trap remains effective. To keep the first generation of slugs at bay, you should bury the beer trap in your beds between November and April. Multiple containers increase success even further.
Plants against slugs
Instead of your vegetables and salad plants, sacrifice herbs that magically attract the reptiles. This includes the student flower. It has special glands on the edges of the leaves and roots that secrete a scent. This is particularly attractive to slugs, which is why Tagetes species are well suited as edge plants for vegetable beds.
Use herbal extracts:
- Mix fern or liverwort extract with water
- spray on crops
- Repeat measure after heavy rain
Plant extracts have a deterrent effect on slugs and are harmless to the plants because they do not penetrate the tissue. However, the molluscs develop different preferences, so you should try different plants and extracts for spraying. Savory and chamomile are also considered effective ways to ward off snails.
Obstacles
Snail fences keep voracious intruders away
Snail fences serve as an insurmountable obstacle for slugs. Alternatively, you can spread a wide layer of lime and sawdust around the beds. This belt is avoided by most snails because the mollusks do not crawl over rough surfaces because of the risk of injury. Lime also burns the sole. The disadvantage of this method is its short-term effect. Rain makes the barrier ineffective, which is why you should spread the substances regularly.
Excursus
Do snails help against slugs?
Many hobby gardeners answer the question “What to do about slugs?” by using snails. They are among the largest native snails and are under protection. Their main diet includes withered plant parts and algae growth.
Cannibalism can sometimes be observed in young snails in the breeding cavity. They eat other young snails and do not stop at clutches. Cannibalism no longer occurs in adult animals. It is a widespread myth that Roman snails feed on other snail eggs.
Caution: observe plant protection law
Not all home remedies are permitted for use in private gardens. Many hobby gardeners classify substances from the kitchen as harmless, but numerous products are poison for nature and its living creatures. The Plant Protection Act therefore prohibits the use of home-made products that are not officially approved as plant protection products and can harm organisms.
Coffee kills beneficial insects
The effect of coffee on slugs has now been proven. When used in low concentrations, coffee grounds have a deterrent effect. Higher doses kill the molluscs after they eat the crumbs. The reason for this effect lies in caffeine, which acts as a neurotoxin. However, there is a risk that beneficial insects will also be affected. According to the Federal Environment Agency, it is not permitted to use self-made coffee brew as a snail control agent.
S alt changes the living space
S alt removes moisture from the snail, so that it slowly dries out and dies. However, s alt can also damage plant roots if it accumulates in the soil. If there are deposits, s alt-loving plants settle in the garden and the actual crops have no chance of survival. Burns may occur on the leaves of treated plants. S alt is therefore considered a poison for the garden.
Which slugs live in the garden?
The black slug is usually deep black
Nudibranchs are species that have almost completely reduced their shells in the course of their evolution. In some representatives, remains of a shell have been preserved in the soft body. This means that the slugs are unable to move into a protective shell. The group is very species-rich and not uniform, because the process of shell reduction took place within different snail families.
The Spanish snail is one of the most common snail species found in Germany. Up to 12 individuals live on one square meter of cultivated land.
Culture pests
There are some representative species that can be considered crop pests. The inconspicuous gray snails, which are just under a centimeter small, are among the most voracious herbivores, along with the red slug and Spanish slug. However, the latter is less picky when it comes to food. Because of its high tolerance to drought and sun, the species has a good chance of survival. These continue to rise as the Spanish slug is despised by snail hunters because of its bitter slime. But other species can also be dangerous to cultivated plants.
| Latin name | Size | Coloring | Abnormalities | |
|---|---|---|---|---|
| Black Slug | Arion ater | 10-15 cm | deep black, rarely gray or dark brown | dark sole |
| Netted field snail | Deroceras reticulatum | 4-6 cm | brown to gray | net-like spots |
| Garden slug | Arion hortensis | up to 50 mm | dark brown to black with a reddish tint | Sole yellowish |
| Red Slug | Arion rufus | 12-15 cm | black, brown, red or orange | elongated wrinkles |
| Spanish slug | Arion vulgaris | 7-15 cm | black, brown, red, orange, yellow | Juveniles yellowish with dark longitudinal band |
Beneficial insects
Even if damage caused by slugs and snails causes displeasure among many garden owners, these molluscs perform important tasks in nature and are therefore also useful. They are considered he alth police because they use decaying plant remains and destroy dead animals. In this way, they keep the garden and beds clean and promote the formation of humus. Due to their diet, slugs are more commonly seen in compost, where they accelerate the decomposition of organic material.
These species are useful:
- Tiger nudibranchs: Snails with a tabby pattern and a striking keel
- worm snails: worm-like snails that eat slug eggs
- Blue fluke: conspicuous species that mainly eats mushrooms and lichens but also strawberries
- Glitter Slug: welcome guests who eat slug eggs
How do slugs reproduce?
Mating of slugs is a slimy affair
Watching slugs mating is a natural spectacle. The molluscs are hermaphroditic and have their sexual and auxiliary organs in a common genital apparatus. All individuals can mate with each other. Sexual partners find each other by following a trail of mucus. Before reproduction occurs, an elaborate mating dance takes place. The following reproductive mechanisms relate to the Spanish slug.
Background
Where do slugs come from?
Approximately 90 percent of all damage caused by snails in the garden comes from the Spanish slug. Little is known about their original origin, so their spread in Europe can only be vaguely reconstructed. The first evidence that the species has spread in Germany comes from the Rhine region and dates back to 1969. In 1980 the Spanish slug was already colonizing large parts of southern Germany.
Find a partner
The mollusks orbit each other in a clockwise direction, producing large amounts of mucus. The mating dance can come to an abrupt end if the snails are in the wrong reproductive cycle or the animals are genetically incompatible. If the dance was successful, reproduction occurs.
Propagation
The animals entwine themselves and press their bud-like reproductive organs together. They evert the epiphallus and spermathecal duct, which is usually not visible to the observer. Through weakly pulsating movements, a spermatophore formed in the epiphallus is pushed into the partner's spermathecal duct. In this phase, the snails can remain almost motionless for several hours.
Breakup
After the snails have separated from each other, they resume their circular movements. They are still connected to each other via the spermatophores, which are anchored in the duct by recurved teeth. With a jerk, the individuals separate from each other, leaving the seed packets in their respective partners.
Development
Since slugs are hermaphroditic, both sexual partners lay eggs
After several days to a few weeks, both partners lay their eggs independently in several clutches. To do this, the snail looks for a moist and protected place on the surface of the earth, or it buries the eggs to a depth of ten centimeters in the earth. Egg laying occurs predominantly from the end of June and reaches its peak between August and September. In mild years, this event can extend into December.
- up to 225 eggs per clutch
- a snail produces between 200 and 500 eggs
- At an ambient temperature of 20 degrees, development takes 30 to 37 days
The eggs laid in summer hatch young in the same year. If the eggs were laid late, the eggs will survive the winter. The young slugs are about ten millimeters long and reach their full body length by late summer.
What do slugs eat?
Snails have a special organ that is unique in the animal kingdom. The so-called rasp tongue (also known as radula) is covered with numerous teeth that are adapted to the food. In herbivores and scavengers, the rasp teeth are uniformly structured so that the plant material can be gnawed.
Tip
Keep the soil in the bed as open as possible so that the surface can dry. Snails do not feel comfortable in this environment.
omnivorous
The slugs are omnivores that feed primarily on plant material, but also eat carrion. Tender young plants or crops with thick-fleshed and juicy leaves are their favorite food. Even ornamental plants are not spared. They usually eat the leaves from the edge until only bare stems remain. Pitting is also typical.
- strong smelling herbs are spared
- tender leaves of cabbage and lettuce are very popular
- Large hosta foliage is not despised
Which animals eat slugs?
Slugs are a delicious meal for hedgehogs
Nudibranchs produce a thick mucus that is used for better movement and protection, but is also effective against natural enemies. Its bitter taste ensures that only a few predators attack slugs. Hedgehogs eat slugs, although they prefer worms, fruit and insects. Shrews, blackbirds, magpies and starlings, along with slowworms and toads, are also snail eaters. Chickens eat slugs that have just hatched or eggs. The larger the snails get, the higher the risk of suffocation for chickens.
These animals are useful egg eaters:
- Ground beetles and their lavas
- Centipede
- Glowworms and their larvae
Preventing the spread of slugs
Thought-out prevention is better than combating it. Create a species-rich garden in which beneficial insects feel comfortable. With a few measures you can make the environment unfriendly to snails so that a mass spread is nipped in the bud.
Soil preparation
Regular digging ensures that the soil is finely crumbly. If there are no cavities, young snails have no place to retreat and are defenseless against their enemies. In autumn you should turn over fallow and coarse soil beds with a cultivator. This brings egg clutches to the surface, where they freeze or are eaten by predators.
Tip
A fine, crumbly and dry soil does not offer ideal living conditions for snails. Improve heavy and clayey soils with sand or compost.
Mulch wisely
Mulch only provides limited protection against slugs
Remove old bark mulch from the beds in spring and dry the material before composting. There may be eggs in the mulch that can also hatch on the compost. If you want to apply a new layer of mulch, you should keep it as thin as possible. Snails do not feel comfortable in fresh and finely chopped softwood bark.
Prefer plants
Many slugs prefer to attack young plants, whose soft leaves are particularly easy to eat. When the leaves have developed a harder tissue, they become uninteresting to many snails. Therefore, protect young plants with snail collars or grow the seeds on the windowsill in the greenhouse. Balanced fertilization is necessary so that the plants can develop solid leaf tissue. Well cared for specimens survive snail damage better.
Planting resilient vegetables
Some plants protect themselves from snail damage with hair, essential oils or leathery leaves. These include marigolds and bearded carnations as well as potatoes, tomatoes and leeks. Mediterranean herbs such as sage, rosemary and thyme are also spurned by snails.
Frequently asked questions
How old do slugs get?
How long slugs live depends on the species, size and environmental factors. While the tiny dwarf snails barely live longer than a year, the Spanish slug has a life expectancy of around three years. Most snails die after laying eggs. Only unfertilized and adult specimens overwinter.
How do slugs overwinter?
The overwintering stage of the Spanish slug is the young animals. The eggs overwinter more rarely, so that young animals do not hatch until the following spring. These stadiums can withstand temperatures down to minus two degrees. While the eggs are already protected in the ground, young snails burrow into the substrate. The adults that survive the winter also hide in deeper layers of soil.
Are slugs poisonous?
Nudibranchs produce mucus to protect themselves from predators. This contains bitter substances and therefore creates an unpleasant taste experience. Some species produce toxins that are secreted in the mucus or stored in the skin. One of these representatives is the ground snail. Slugs are usually harmless to humans.
Where do slugs live?
Since the animals do not have a protective housing, they have to seek protection in the surrounding area. During the day, slugs prefer to crawl around under the protective plant cover, between piles of wood or on the compost. Only at night, when the heat has subsided, do the molluscs come out of their hiding places.
How do slugs form?
The molluscs are hermaphroditic and reproduce by bonding with a partner. If two animals find each other through the trail of slime, a snail dance occurs. The partners then press against each other so that their sexual organs connect. They exchange seed packets through rhythmic movements before breaking away and going their separate ways. Each animal lays eggs independently, from which young animals hatch after a few weeks. Temperatures between ten and 25 degrees Celsius are necessary for successful development.