Everyone who has ever had their own plot has encountered a slug. Its appearance is quite unpleasant, and many people treat this mollusk with contempt. They may have a reduced shell or without it and are terrestrial gastropods. They appear after rain and give gardeners cause for concern. Their size can be from 2 to 20 centimeters, and sometimes 30, like roadside slugs.
General information about the mollusk
The mollusk has an elongated, elongated body that can change its shape due to muscle contractions. Its body consists of three sections: head, legs and visceral mass. The legs and torso are separated by a circular groove. The head has tentacles on which the sensory organs are located. Behind the head there is a mantle with a pulmonary opening leading to the mantle cavity, which, in fact, performs the function of the lung.
They are always covered with mucus. This is a protective reaction against drying out. Coloring can be varied. They are found in gray, brown, yellow and even black. May be spotted. Some types of slugs are bred in aquariums and are considered pets.
Varieties of slugs
Slugs prefer damp places. If the soil is dry, they die or become buried in the ground. Very often they can be found in the forest or in the garden. An excellent place for them is thickets of bushes. They can also live in the far corners of parks, where there is a body of water nearby. They feed on leaves, mushrooms, berries and flowers. Some species feed on worms. They cannot live in hot places. These mollusks are not found in deserts.
There are many types of slugs. Many of them are pests. The most common are:
- large roadside;
- black;
- banana;
- nautical;
- malakolimax gentle;
- giant blue;
- reticulate;
- field;
- smooth.
In nature, there are several hundred species of this mollusk.
Reproduction [edit | edit code ]
Terrestrial slugs are characterized by hermaphroditism (sometimes sequential) and cross internal fertilization.
Slugs have both female and male reproductive organs. Typically, a slug will follow the mucus of another slug, and may even eat that mucus. Then the slugs find each other and begin to circle together. At the same time, they release their genitals. The slugs move close to each other and their genitals touch the partner. Sperm is transported in the form of a spermatophore. After a few days, the slug lays about 30 eggs in a hole in the ground. Some species overwinter underground in temperate climates; in other species, adults die in the fall.
A common practice among many slugs is apophalation, where one or both slugs bite off part of the penis. The penis of these species is twisted like a corkscrew and often becomes entangled in the partner's genitals during the exchange of sperm. Apophalation allows the slugs to separate. It is believed that damaged genitals grow back like "tentacles of vision."
Some varieties of slugs can impregnate each other by "throwing" tiny droplets of sperm that they shoot toward their partner's genitals.
Characteristics of representatives
Large roadside is the most common species in the garden. It is large in size. Sometimes it is called leopard print. Its color is gray-spotted.
The blue slug is often called the Carpathian slug. This is due to the fact that it is found only in the region of these mountains. It is large in size and brightly colored. Prefers coniferous and deciduous forests of Ukraine, Poland, Slovakia and the Czech Republic. Its diet includes russula, which is what gives the giant blue slug its amazing color. The accumulation of this species will be a tip to the mushroom picker. This means that there is a mushroom clearing nearby somewhere.
The naked slug is the most famous species in Russia. This annoying pest not only lives in the garden, but also loves greenhouses and greenhouses. Leaves large holes on fruits and leaves.
The black type of mollusk is the largest. Some individuals are up to 30 centimeters long. Mushrooms are what slugs of this species eat. He also loves root vegetables.
Another large representative is the banana slug. It is not found in banana plantations and will not look like a banana, but is a bright yellow color. It feeds on lichen, mushrooms and rotten leaves.
Small species include the field slug. Its dimensions do not exceed 5−6 centimeters. It lives in valleys and on the edges of forests. Young shoots and wild berries make up its diet. Comes in all shades of brown.
In moss thickets you can find whole groups of reticulated slugs. This species loves loose soil and rotten leaves. He is one of the smallest representatives. Its dimensions do not exceed 3 centimeters. Very often has a spotted color.
Enemies of shellfish
They have quite a lot of enemies. The sun is their main enemy, as they cannot tolerate high temperatures and die. They are loved by predators, such as wild boars. Some vertebrates feed on them. They are food for shrews, hedgehogs and moles. Rodents won't refuse them either.
Snakes, frogs and lizards often feast on slugs. There are a lot of their enemies among birds. Rooks, starlings, storks, gulls, jackdaws and many other birds prefer to feed on them. Among domestic animals, ducks and chickens should be noted, which do not refuse slugs.
Insects are also a threat to shellfish. They are part of the regular diet for ground beetles. Grasshoppers also feed on them. There are many who eat slugs in nature.
Interesting facts [edit | edit code ]
Sea slug Elysia chlorotica
assimilates chloroplasts of the algae
Vaucheria litorea
into the cells of the digestive tract. Chloroplasts are able to photosynthesize in the slug's body for several months, allowing the slug to live off the glucose produced by photosynthesis. The slug genome encodes some of the proteins required by chloroplasts for photosynthesis. [6]
Description of the slug clan
- Fact:
It is not so easy to detect the harmful guests themselves, but traces of their presence remain everywhere. - Fact 2:
They are awake at night, during the day they hide from the sun’s rays under the leaves of plants, and in the morning one can only lament the results of their feasts. - Fact 3:
Slugs are omnivores and do not disdain almost any plantings in the garden. - Fact 4:
Slugs have gained great popularity in the pet market.
Diet and harm to the garden
Most varieties of this mollusk cause enormous harm not only to gardeners and gardeners, but also to the entire agriculture industry in general. They feed on more than 150 types of vegetables and fruits; they love not only root vegetables, but also foliage and shoots of plants. They give preference to potatoes, beans, cucumbers, strawberries, tomatoes and many other vegetables, fruits and berries. But they avoid garlic, onions, mustard and basil.
Very often, entire grape and citrus plantations are under threat of destruction from this pest. Rye and winter wheat are often affected by slugs. They feed not only on grains, but also on seedlings. They avoid buckwheat, flax and spring wheat.
This is a real disaster for gardeners, as they spread incredibly quickly in the garden. And all because:
- lay dozens of eggs;
- develop rapidly to reproduce;
- are hermaphrodites and do not need a partner.
Slugs are a source of viral, bacterial and fungal diseases. For this reason, the entire crop often perishes. Crawling from one place to another, they spread the infection everywhere. They spread diseases such as:
- cabbage spot;
- potato late blight;
- downy mildew of beans.
These diseases will be destructive to the crop. They will not leave aside the ornamental plants on the site. These voracious mollusks eat everything from seeds to roots and leaves. They are most active at night. They like to appear after the rain. Slugs are carriers of parasites. Pets are at risk of becoming infected with different types of helminths.
There can be many reasons for the mass spread of a pest:
- not very cold winter;
- rainy summer;
- wet but warm autumn;
- early spring.
It's difficult to fight them. It is better to take preventative measures. If slugs appear, you must get rid of them immediately, otherwise the harvest cannot be saved.
Fighting slugs
Netted slug
Everyone has encountered slugs in their garden, however, due to their secretive lifestyle, one may get the impression that these mollusks are of low harmfulness. Meanwhile, when in large numbers, they can cause significant damage.
It is estimated that slugs damage about 150 species and varieties of cultivated plants, including cabbage and cauliflower, lettuce, peas, beans, tomatoes, cucumbers, carrots, potatoes, strawberries and many ornamental plants. If there are no cultivated plants, slugs readily feed on weeds: burdock, coltsfoot, dandelion, plantain, etc.
In addition to reducing the yield, slugs worsen the commercial quality of products and contaminate them with secretions. Damaged vegetables become unsuitable for storage and quickly rot. In addition, by damaging plants, slugs contribute to their infection with diseases such as gray rot of strawberries, downy mildew of peas, etc. This. occurs because slugs carry spores of fungi that cause diseases. And then, the damage caused by slugs is an open gate for the penetration of fungal and other infections.
This, however, does not exhaust the harm caused by slugs . Together with other terrestrial mollusks, they are intermediate hosts for a number of parasitic worms that live in the body of domestic animals. Thus, mollusks infect domestic chickens with the worm Daweinia, which causes a serious disease, Daweineosis, accompanied by severe exhaustion and paralysis of the bird, and often its death. Many slugs and snails become intermediate hosts for other parasitic worms that develop in various organs of sheep, goats and cattle, which leads to a decrease in their productivity and sometimes to the death of young animals. This is why you should not feed slugs and snails to pets. It must be said that not all slugs harm plants. Some of them live in forests and parks and feed there mainly on mushrooms, which have no practical significance for us.
Slug eating a leaf
Several species of slugs are found in gardens and vegetable gardens in the North-West. The most numerous of them are netted and field slugs . Small creatures 30-50 mm long are somewhat different from each other. The reticulated slug has a clear pattern formed by brownish, dark brown or black spots and streaks. The field slug is whitish in color, with a slight brown tint, without a dark pattern, its body is more slender than that of the reticulated slug, fusiform. If the first prefers plowed areas, then the second clearly gravitates towards meadows.
Both species give one full generation during the warm season. In the spring, young slugs hatch from eggs that have overwintered in the soil. They are almost transparent, 3-4 mm long. At first they feed on soil humus, but after 10-14 days they are already capable of causing significant harm to plants: gnawing the embryos of germinating seeds, eating the tender leaves of seedlings and seedlings in greenhouses. The greatest appetite of slugs coincides with their puberty and reproduction (usually 1.5-2 months after hatching from eggs). During this period, pests are able to completely destroy lettuce, cabbage, potatoes and other crops, eat strawberries, various ornamental plants (asters, dahlias, gladioli, irises, etc.). Later, slugs begin to feed on ripening fruits of cucumbers, tomatoes, zucchini, root crops of carrots, turnips, rutabaga, as well as potato tubers located near the soil surface. Mollusks gnaw holes in them, often eating through passages. On plants damaged by slugs, excrement and mucus remain, which can be used to judge the culprits of the damage.
Slugs are bisexual creatures (hermaphrodites), combining the characteristics of a male and female body. One slug, under favorable conditions, can lay up to 500 eggs. Eggs are laid in the soil at a depth of 5-8 cm, as well as under various objects (piles of weeds and tops, boards, stones, etc.). The diameter of the eggs is 1.5-2 mm, at the beginning of development they are transparent, then light brown. Usually, slug eggs remain for the winter, but in a warm autumn, a second (autumn) generation may hatch from some of the laid eggs, which remains to winter and can cause harm in early spring, after the destruction of the snow cover. Sometimes slugs damage vegetables and fruits stored in cellars.
In addition to the named species of mollusks, in the central regions of the Non-Black Earth Region and in the south there is also another species - spotted slug . It is large, up to 120 mm long. In more northern regions, the spotted slug is found exclusively in heated rooms - winter greenhouses and greenhouses, where it is involuntarily brought along with plants. The spotted slug can cause great damage to vegetable and ornamental plants in protected soil, as well as to mushrooms. This slug lives 2-2.5 years.
Field slug
It is necessary to constantly clear the area of stones, weeded weeds, tops, scraps of plastic film, burlap, under which pests accumulate. Slugs are also attracted to dense plantings: a moist and cool microclimate favorable for them is created here.
So maintain normal stem density, especially in rainy years.
By controlling weeds, you also reduce the harmfulness of slugs. After all, mollusks feed on weeds before the appearance and after harvesting of cultivated plants.
When cultivating the soil, keep in mind: careful cutting of the arable layer, creating a finely lumpy soil structure devoid of blocks, leads to a sharp decrease in the number of slugs. Fewer voids in the soil means fewer slugs. Early sowing of seeds and planting seedlings in the spring is preferable from the point of view of combating slugs, since in this case the plants will have time to develop and strengthen even before the mass hatching of mollusks from overwintered eggs. It has been established that rolling the soil after sowing seeds reduces the damage to plants by slugs by 1.5-2 times: the penetration of slugs into seeds and seedlings is noticeably difficult.
In the fall, after harvesting, it is very important not to leave any vegetation on the site that slugs can feed on. If this rule is followed, pests will be deprived of food during the extremely important breeding period for them, they will lay fewer eggs and their numbers next year will be low.
The mechanical method of dealing with slugs is primarily the manual collection of mollusks (preferably using tweezers), the creation of protective strips and grooves. Slugs are collected from plants and soil during the day in wet weather, especially after rain, and early in the morning when there is dew. At this time, the mollusks are actively crawling and feeding. To collect and destroy pests, you can use traps - shelters (pieces of plywood or burlap, piles of weeds and tops), which must be placed evenly at a distance of 3-5 m from each other. They are periodically inspected and slugs collected.
Protective grooves and strips 15-30 cm wide are made of material that impedes the movement of slugs - pine needles, sand, sawdust, and are placed around beds with plants. However, it is not always possible to protect plants using these techniques. , chemicals cannot be avoided . The industry produces a 5% granular preparation of metaldehyde prepared from coarse wheat bran. The consumption rate of the drug is 3-4 g per 1 m2, treatment can be twice, the last of which is carried out no later than 20 days before harvesting the protected crop. Metaldehyde granules are scattered on the soil surface or placed in the shelter traps described above. The mollusks actively search for and eat the poisoned bait, quickly lose mobility and die. To ensure that the drug remains toxic to slugs longer, it can be placed under small umbrellas to protect the bait from rain. They are easy to make: connect two tin lids in the center with a 5 cm long rod. The bottom lid will serve as a base on which metaldehyde is placed, and the top one will protect it from raindrops.
In the absence of a metaldehyde preparation, copper or iron sulfate, fluff lime, and ground superphosphate can be used to combat slugs. However, in wet weather their effectiveness is low: slugs are easily cleaned of caustic particles that fall on them due to abundant mucus secretion.
The number of mollusks can be reduced by attracting their natural enemies to the site. And slugs are eaten by brown frogs, toads, legless lizards - spindle and yellow-bellied lizard, as well as hedgehogs. Our feathered friends also help deal with slugs: wagtail, lapwing, jay, magpie, hoodie, jackdaw, blackbirds, common starling, crested lark, shrike and others. Taking care of your birds throughout the year will help reduce the number of slugs and other pests in your yard.
Y. Shapiro, Candidate of Biological Sciences
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Pest Control
Experienced gardeners know many tricks on how to deal with slugs. However, this is a labor-intensive task and requires a lot of effort and patience. You should weed your area as often as possible. Pests don't like this. You should not leave garbage in your garden or garden. You can sprinkle the border of your property with coffee grounds or pine needles. This will be an obstacle for mollusks. Some gardeners use chlorine for this purpose. It is recommended to get rid of weeds.
Pest traps are popular. This could be mowed grass, damp moss, old wet rags, or even a can of beer, the smell of which will attract a slug. Such traps should be set at night, and pests should be collected in the morning. An infusion of pepper that is sprayed on the area will be effective in combating them.
If the number of parasites is large, then drastic measures will have to be taken. It is better to use chemicals. But this can be done before the harvest ripens. If it’s already time to pick vegetables and berries, then harmless methods of spraying plants will do. Mustard solution will prove to be an effective remedy in the fight against the voracious mollusk. Many gardeners use a cheap saline solution.
They are not afraid of the first frosts and burrow into the soil. From early spring they begin their harmful activities. Until late autumn, slugs feed on the harvest of gardeners.
