Everyone has met slugs in their garden , however, due to their secretive lifestyle, one may get the impression that these mollusks are not very harmful. Meanwhile, with a large number, they can cause significant damage.
It is estimated that slugs damage about 150 species and varieties of cultivated plants, which include white 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, pollute it with secretions. Damaged vegetables become unsuitable for storage – 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. This happens 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 from slugs . Together with other terrestrial mollusks, they are intermediate hosts for a number of parasitic worms living in the body of domestic animals. Thus, molluscs infect domestic chickens with the daweinia worm, 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 of 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 shouldn’t feed slugs and snails to your pets.
I must say that not all slugs harm plants. Some of them live in forests, parks and feed there mainly on mushrooms that have no practical significance for us.
Several species of slugs are found in the gardens and orchards of the Northwest. The most numerous of them are reticulated 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 strokes. 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 reticulate, spindle-shaped. 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 able to cause significant harm to plants: gnaw out the embryos of germinating seeds, eat tender leaves of seedlings and seedlings in greenhouses and greenhouses. The greatest appetite of slugs coincides in time 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, gladiolus, irises, etc.). Later, slugs begin to feed on the 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. Excrement and mucus remain on plants damaged by slugs, which can be used to judge the perpetrators of the damage.
Slugs are bisexual creatures (hermaphrodites), combining the signs 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 (heaps of weeds and tops, boards, stones, etc.). Eggs are 1.5-2 mm in diameter, at the beginning of development they are transparent, then light brown. Slug eggs usually remain for wintering, however, in warm autumn, the second (autumn) generation may hatch from part of the eggs laid, which remains to winter and can harm already 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, another species comes across – spotted slug . It is large, up to 120 mm long. In the 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 ground, as well as champignons. This slug lives 2-2.5 years.
It is necessary to constantly clean the area from stones, weeded weeds, tops, scraps of plastic wrap, burlap, under which pests accumulate. Slugs are also attracted by thickened crops (plantings) of plants: a humid and cool microclimate favorable for them is created here.
So observe the normal density of the stem, especially in rainy years.
By fighting weeds, you 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, the creation of a finely cloddy, devoid of lumps, soil structure, leads to a sharp decrease in the number of slugs. Less voids in the soil means fewer slugs. Early sowing of seeds and planting seedlings in spring is preferable from the point of view of slugs control, since in this case the plants will have time to develop and get stronger 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 to 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. Subject to this rule, pests will be deprived of food during the breeding season, which is extremely important for them, they will lay fewer eggs, and their numbers will be low next year.
The mechanical method of dealing with slugs is primarily a manual collection of mollusks (preferably with tweezers), the creation of protective strips and grooves. They collect slugs from plants and soil during the day in wet weather, especially after rain, and early in the morning – in dew. At this time, the molluscs are actively crawling and feeding. To collect and destroy pests, you can use traps – shelters (pieces of plywood or burlap, heaps of weeds and tops), which must be placed evenly at a distance of 3-5 m from each other. They are periodically viewed and collected slugs.
Protective grooves and strips 15-30 cm wide are made of material that impedes the movement of slugs – needles, sand, sawdust, and are placed around beds with plants.
However, it is not always possible to save plants using these techniques. With a high number of slugs, you can not do without chemicals . The industry produces a 5% granular preparation of metaldehyde, prepared on coarse wheat bran. The consumption rate of the drug is 3-4 g per 1 m 2, processing can be double, the last of them 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. Mollusks actively seek out and eat the poisoned bait, quickly lose their mobility and die. To keep the drug longer toxic to slugs, it can be placed under small umbrellas that protect the bait from rain. Making them is simple: connect two tin lids in the center with a 5 cm long rod. The lower lid will serve as the base on which metaldehyde is placed, and the upper one will protect from raindrops.
In the absence of a metaldehyde preparation, copper or iron sulfate, fluffy lime, and ground superphosphate can be used to fight slugs. However, in wet weather, their effectiveness is low: slugs are easily cleared 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, as well as hedgehogs. Our feathered friends also help to deal with slugs: wagtail, lapwing, jay, magpie, gray crow, jackdaw, blackbirds, common starling, crested lark, shrike and others. Caring for birds throughout the year will help reduce the number of slugs and other pests in your yard.