VIVOS VOCO: Grodnitsky D.L., “Siberian silkworm and the fate of the fir taiga.” Description and photo of the caterpillar and butterfly of the Siberian silkworm. The difference between the pine cutworm and the Siberian silkworm.

Russian ecologists, geneticists and biologists are sounding the alarm: this summer caterpillars pine silkworm We reached the Curonian Spit of the Kaliningrad region and the forests of the Vyatka region. Together with the Siberian silkworm, they actively destroy coniferous forests, causing irreparable harm.

The Siberian silkworm is one of the most dangerous pests coniferous forests, which is widespread in the Siberian and Ural regions. The butterflies themselves are not dangerous: only silkworm caterpillars cause damage to trees; they feed on pine needles, as well as the bark of thin shoots and cones. Their life cycle stretches for 2 years, during which part of the time they actively feed, and during the winter they hibernate. The silkworm is dangerous because, under favorable conditions for development and reproduction, the caterpillars eat the needles, that is, they weaken the viability of coniferous trees, subsequently the trees are attacked by secondary pests and the forests eventually die. The Siberian silkworm damages about 20 species of coniferous trees: from larch to spruce. Larches that were killed by silkworms are restored no sooner than after 200 years. IN last years this pest appeared in the Perm and Udmurt regions.

Pine silkworms prefer black pine, but if there is none nearby, they will happily feed on any other species. They have impressive claws that allow them to get any pine needles: thick or thin, hard or soft, smooth or rough. Their unpretentiousness in food is their undoubted advantage. When weather change, they settle at a certain height and look for their favorite trees. Caterpillars are not bothered by the cold; they are one of the few insects that can easily survive 3 months of winter. Their winter cocoon is not afraid of bad weather. As insects grow, the cocoon becomes denser and larger. As each caterpillar moves, it wraps a silk thread around it. For 3 winter months chaotic movements, the cocoon noticeably grows. As for the threat of the pine silkworm to humans: the hairs of this insect are extremely dangerous to health: they get on the skin, in the respiratory tract and cause severe attacks of allergies. If help is not provided in time, the person may suffocate. You need to be extremely careful with silkworm caterpillars. The insect's hairs are carried by the wind, they stick to the grass and can be deadly to humans.

Local biologists believe that this is all due to the disruption of the unique ecosystem natural area Curonian Spit. Small settlements local residents are being replaced by luxury hotels, the forest is being cut down. Sewage flows directly into the bay.

To find out whether silkworms have appeared in the forests, Rosselkhoznadzor specialists install pheromone traps. The trap contains a pheromone capsule and an adhesive surface to which the butterfly sticks when it flies to the smell of the pheromone. Butterflies fly from mid-July to August. At this time, traps are set, this makes it possible to determine the presence and number of silkworms in a given area in this period and take action necessary measures. A preliminary examination of whether an insect is a quarantine pest or just a forest resident is given in the laboratory of the Institute of Plant Quarantine.

Pine silkworm caterpillars began their spread from eastern Spain and northeastern Italy, gradually they reached the northern regions of Europe, and now they are actively devouring forests in Russia and spreading further and further.

The invasion of these caterpillars is worse for the forest than a fire; for humans it is fraught with a threat to health and life.

Let's talk about Siberian silkworm is a type of butterfly that lives in coniferous forests. It is quite large in size, for example, its wingspan reaches sixty to eighty millimeters in the female, and forty to sixty centimeters in the male. It belongs to the family of cocoon moths. Its caterpillars feed on coniferous trees. She especially prefers trees such as larch, spruce, common pine and fir.

A distinctive feature of the male is his antennae; they have a feathery shape. Butterfly wings are brown with different shades: yellow, gray and black. The front wings, if you look closely, have three stripes, usually dark in color, and in the middle there is a large spot white. The wings that are located at the back are mostly one color.

Butterflies begin to fly from mid-July, and their flight lasts until mid-August.

What kind of eggs do they have? About two millimeters in diameter, spherical in shape. If you look at them, then on each egg you can see a brown dot, and the color of the eggs itself is green with blue and turns into grey colour. There can be thirty, forty or more of them in one clutch, sometimes up to two hundred. The eggs develop over about thirteen days, sometimes up to twenty-two. After this, the caterpillar emerges from mid-August and feeds on needles. She lives, feeds and develops into a more adult individual. In the month of September, towards the end, the caterpillar prepares for wintering. It overwinters under moss and fallen pine needles, being in a state of complete dormancy. In the spring, when the snow has melted, the caterpillar crawls into the crowns, where it lives there all the time until autumn.

The length of the caterpillar is approximately fifty-five to seventy millimeters. It is usually brown or brown in color.

The caterpillar actively feeds and, having acquired the necessary nutritional elements, in June wraps itself in cocoons, which are very dense and gray in color. The pupa develops over a period of three to four weeks.

The pupae reach a length of twenty-eight to thirty-nine centimeters. The color of the pupa is light, then turns into brown, and over time, as it grows, it becomes almost black.

In Russia, the Siberian silkworm lives within the Urals, also in Siberia, where there are especially many coniferous trees. It spread over quite a lot large territory. It is also common in Asia: Kazakhstan, Mongolia and other countries. The difference in temperature does not frighten it much and therefore it is widespread from Siberia to Asia and beyond. This type of silkworm is considered a pest forest trees. The spread of the Siberian silkworm towards the west is also noted.

U Siberian silkworm there are enemies - these are equestrians, braconids, egg eaters, and ibraconids. These natural enemies destroy the Siberian silkworm, regulating their numbers. He has something to eat, where to live, he reproduces, like everything in nature, and has his enemies. Such a description revealed to us more the diverse and surprisingly harmonious world of nature.

The Siberian silkworm (otherwise known as the hemp moth) is a dangerous insect pest that damages more than 20 species of coniferous trees. The insect is especially destructive for larch, fir, and cedar. Spruce and pine are damaged much less frequently by butterflies.

The Siberian silkworm is a quarantine species. Even if it is absent on the territory of the country, there is a real threat of its independent penetration or introduction from the outside, which can lead to massive damage to plants and plant products. That is why it is strongly recommended to carry out phytosanitary measures: when exporting conifers, they must be disinfected or debarked.

An adult Siberian silkworm (photo) reaches 10 cm, females are larger than males. The insect lays about 200 eggs (sometimes up to 800) on tree branches. The butterfly does not feed, but the larva that hatches after 2-3 weeks immediately begins to eat the needles, moving to the very top of the crown. With a lack of nutrition, the Siberian silkworm caterpillar can damage the bark of trees and young cones. In autumn, the caterpillars go to winter. In the spring, their active life activities resume. Pests go through 6–8 instars.

Upon completion of the development cycle, the caterpillars weave a dense cocoon in which pupation occurs. The pupae grow for 3–4 weeks; at the end of June, adults emerge from them and begin mating.

As a rule, the Siberian silkworm is found in small numbers in healthy forests. A population outbreak (mass reproduction of an insect) can lead to an environmental disaster. Drought is one of the main reasons for this phenomenon. During dry seasons, the caterpillar manages to develop not in two, but in one year. The population doubles; the butterfly’s natural enemies do not have time to infect a sufficient number of individuals. Butterflies reproduce unhindered and give birth. Early spring fires are another reason for outbreaks of silkworm numbers. The fact is that silkworm caterpillars overwinter on the forest floor. Telenomus also lives there - worst enemy eating silkworm eggs.

And early spring fires destroy most of the Telenomus population, which leads to the emergence of centers of mass distribution of silkworms.

In addition to telenomus, the natural enemy of the silkworm is the cuckoo, as well as fungal infections.

Hereby sword of Damocles became the Siberian silkworm for coniferous plantations in Siberia and the Far East, where its invasion, comparable to an invasion of locusts, destroyed more than one thousand hectares of coniferous forest, including young spruce and pine seedlings. Huge territories have turned into bare, treeless spaces. According to some scientists, it will take about a hundred years to restore these forest plantations. According to others, restoration of forest plantations after damage by the pest is impossible.

When mass reproduction of the Siberian silkworm occurs, it is very important to treat plants with insecticides. Lepidocide is one of the most effective drugs. To prevent the spread of the butterfly, it is necessary to regularly inspect the plants and treat them with insect repellents.

A dangerous pest of forests and cultural plantings, the gypsy moth has a wide distribution area. This pest can be found in Asia, Europe, North Africa, in North America. It covers the entire territory of Russia, found in the south, Siberia and the Far East. Deciduous tree species are especially affected by caterpillars. In the absence of food, silkworms move to young coniferous trees. Once in the nursery, insects can cause significant damage to the plantings.

What does a gypsy moth look like?

The gypsy moth is a butterfly belonging to the order of Lepidoptera from the family of moths. Distinctive features of these insects there are noticeable differences between male and female individuals.

Differences in adults are noticeable in color and shape:

1. Females - the size of the wings when unfolded reaches 90 mm. The thick body has the shape of a cylinder. A grayish fluff is visible on the abdomen. The antennae are thin and long.
2. Male - wingspan 40-50 mm, body thin, covered with hairs. The color of the wings is brown, the surface is covered with a pattern of dark spots and broken lines. The antennae are comb-like.

Gypsy moth butterflies prefer open forests, dry places with sufficient light. The first centers of spread are usually located on the edges. During droughts, large outbreaks of mass reproduction of silkworms occur. This species is the leader among pests in terms of the number of outbreaks of reproduction and the duration of these periods.

Reproduction of silkworms

Heavy females rarely fly; they sit on the bark of trees and attract males using pheromones. Males start flying a few days earlier. They are especially active in the evening. They fly long distances in search of a mate. After fertilization, females lay eggs under the bark of trees at a height of 3-4 m. They round shape, yellow or pinkish in color. Size – 1 mm, number of eggs in a gypsy moth clutch – 100-1000 pieces. The insect spends most of its life in the egg state - about 8 months.

An embryo is formed inside the egg shell, which remains to overwinter. In spring, when the temperature rises to +10 0, the first caterpillars appear. They sit motionless for some time, then crawl along the tree. The body of small caterpillars is covered with bristles and air bubbles. This allows them to travel with gusts of wind. To travel long distances, insects can release webs.

Interesting fact. The caterpillar is the only form gypsy plant, which feeds, accumulating energy for the remaining phases of development.

The gypsy moth belongs to the cocoon moth family. The caterpillar appears with sixteen legs. At birth she is light yellow, but quickly darkens and turns brown or black. There are several longitudinal rows of warts on the body.

Information. Gypsy moth eggs are extremely resilient; they can withstand temperatures down to -50.

After settling in new territory active feeding begins. Young caterpillars eat in daytime, gnawing small holes in the leaves. After 3-4 months, they switch to feeding at night, eating the entire leaf. In addition to foliage, the pests’ diet includes buds, young shoots, and flowers. Depending on the climate zone caterpillars take 50 to 80 days to develop. They then pupate. This occurs in June-July, the pupal stage lasts 10-15 days.

Information. Optimal temperature for insect growth +20-25, if it drops to +10, development stops. Male caterpillars up to the adult stage ( adult) experience 5 larval stages, females - 6 stages.

Distribution and harm

The pest has a wide distribution area. In Europe it is found up to Scandinavia, in Asia it covers many countries: Israel, Turkey, Afghanistan, Japan, China, Korea. The story of how a butterfly got into North America. The insect was introduced artificially to conduct experiments on crossing with other species. The larvae managed to spread from the experimental area into open forests. The problem that arose was not given due importance and within a few years the gypsy birds took over a huge territory. It was not until 1889 that the gypsy moth was recognized as a pest. But the insect has already firmly established itself in the new territory.

Interesting fact. Due to their wide distribution area, butterflies are divided into races. In Russia there are Far Eastern, European, Siberian and other races.

The gypsy moth caterpillar denudes deciduous trees in forests and gardens. She prefers fruit trees: apple trees, plums, and apricots. IN wildlife chooses oak, birch, linden. Avoids ash and alder. IN total The pest eats about 300 plant species, not excluding conifers. The main division occurs into the European and Asian races. The Asian group is a true polyphagous, feeding on various types of trees and bushes.

Varieties of gypsy moths

Gypsy moth butterflies are classified into different species depending on their habitat and feeding habits. Among the common groups:

This is a small representative of its species. The size of the wings of females is 40 mm, males 30 mm. The insect is common in Europe and Asia. The caterpillar will grow to 55mm and is grey-blue in color with white and yellow stripes. Pests live in colonies and create spider nests. When fighting gypsy moths, it is necessary to cut and burn the branches where the ovipositor is seen. The trees themselves are sprayed with insecticides.

Male and female gypsy

Traveling silkworm

The traveling silkworm is characterized by the ability of caterpillars to migrate to new feeding areas. At the same time, they line up in a long chain, following each other. The first caterpillar, which is the leader, releases a silk thread along which the rest of the insects are guided. There are two types of traveling silkworms: oak and pine.

Pine cocoon moth

Insects are common in coniferous forests of Siberia and Europe. They damage pine plantations, less often than other species. Grayish-brown females measure 85 mm, males – 60 mm, caterpillars – up to 80 mm. Caterpillars spend the winter in the ground under tree trunks. They rise to feed in the spring and pupate in July.

Siberian silkworm

The gypsy moth feeds on coniferous trees. This species damages spruce, pine, cedar and fir. The insect settled in the forest and forest-steppe zone Siberia. The northern border of its distribution runs along the Arctic Circle. The development of a silkworm from egg to butterfly in a cold region takes 2 years. IN warm years it may accelerate to a one-year cycle. Siberian silkworm butterflies are distinguished by a variety of colors. Adults of brown, gray, and black colors are found. The wingspan of females is 6-10 cm, males have more modest sizes - 4-7 cm. Three dark jagged stripes run across the front wings. Hind wings Brown. The head and chest match the color of the front wings.

The clutch of butterflies is bluish in color, the size of the eggs is 2 mm. They are deposited in uneven piles of 100 pieces. They are located in the bark, on needles and twigs. When the larva appears, it eats half of the shell. The caterpillars grow up to 11 cm, their bodies are gray or black. There are blue hairs on the back. Insects are capable of receiving threatening pose. At the same time, they raise the front part of the body and bend their head. A bright yellow stripe runs along the sides. The body is covered with hairs, in the front and on the sides they are the longest.

The caterpillar's head is brown, with orange spots. The Siberian silkworm pupa is dark, almost black. Its length is up to 5 cm, the cocoon is suspended on branches or between needles. Stinging hairs are woven into its shell. Local silkworms are divided into three races:

• larch;
• fir;
• cedar

Silkworm caterpillars easily tolerate the cold; they go to winter at temperatures close to 0 0 . They crawl into trees after wintering immediately after the snow melts. As it grows, resistance to frost increases.

Information. At frosts down to -10, the caterpillars die, and they do not survive winters with little snow.

Pest control methods

Identification of gypsy insects occurs by gnawed leaves, excrement, butterflies and ovipositors in the web. Basic information is learned by studying the imago and the number of eggs in the clutch. This provides information for forecasting and allows us to determine the phase of the outbreak. Pest control methods are chosen depending on the extent of their spread.

Attention. The Siberian and Far Eastern races of silkworms pose a quarantine danger. Cargo is thoroughly inspected and Vehicle, coming from the Siberian region. Pests are lured out using pheromone traps.

How to deal with gypsy moth in your garden? You should carefully monitor the trees. When signs of damage by caterpillars appear, begin destroying the ovipositors. They are noticeable among the foliage; the nests are cut off and burned along with the eggs. Caterpillars can be collected by hand; this tedious procedure can be done with small areas. Effective method– installation of adhesive rings, crawling caterpillars will stick to the surface of the traps. In autumn, clutches of eggs are scraped from the bark of trees.

Attention. Wear protective gloves when working to exterminate pests.

The use of insecticides is the most effective measure to combat gypsy moths in the garden and forest area. At the beginning of spring, trees are treated with Chlorophos, Metaphos, as well as organophosphorus compounds.

The Siberian silkworm - Dendrolimus superans - is a subspecies of the large coniferous silkworm Dendrolimus superans. Wingspan 65-90 mm. Caterpillars feed on almost all conifers.

Since the Siberian silkworm can only be recognized as a subspecies, its ecological and morphological forms should be considered tribes. The Siberian silkworm varies greatly in color - from yellowish to brown, sometimes almost black.

There are three such tribes in Russia: larch, cedar and Ussuri. The first occupies almost the entire range of the subspecies. Cedar and Ussuri have limited distribution.

Butterflies are especially active during sunset hours. Immediately after mating, females lay eggs on needles, mainly in the lower part of the crown, and during periods of very high numbers - on dry branches, lichens, grass cover, forest floor. In one clutch there are usually several dozen eggs (up to 200 pieces), and in total the female can lay up to 800 eggs, but most often the fertility does not exceed 200–300 eggs.

Eggs almost spherical, up to 2 mm in diameter, first bluish-green with a dark brown dot at one end, then grayish. Egg development lasts 13–15 days, sometimes 20–22 days.

The color of the caterpillars varies from gray-brown to dark brown. The body length of the caterpillar is 55–70 mm, on the 2nd and 3rd body segments they have black transverse stripes with a bluish tint, and on the 4–120th segments there are black horseshoe-shaped spots.

The first molt occurs after 9–12 days, and after 3–4 – the second. In the first instar, the caterpillars eat only the edges of the needles; in the second instar, they eat the entire needle. At the end of September, the caterpillars burrow into the soil, where, curled up in a ring, they overwinter under the moss cover.

At the end of April, the caterpillars climb into the tree crowns and begin to feed, eating whole needles, and if there is a lack of food, the bark of thin shoots and young cones. After about a month, the caterpillars molt for the third time, and again in the second half of July. In the fall they leave for the second winter. In May-June of the next year, adult caterpillars feed intensively, causing greatest harm. During this period, they eat 95% of the food needed for full development. They molt 5–7 times and, accordingly, go through 6–8 instars.

Caterpillars feed on the needles of almost all coniferous species. In June they pupate; before pupation, the caterpillar weaves a brown-gray oblong cocoon. The pupa, 25–45 mm long, is initially light, brownish-red, then dark brown, almost black. The development of the pupa depends on temperature and lasts about a month. Massive yo butterflies occur in the second ten days of July. On the southern slopes of the mountains it occurs earlier, on the northern slopes later.

The development cycle of the Siberian silkworm usually lasts two years, but in the south of the range development almost always ends in one year, and in the north and in high-mountain forests there is sometimes a three-year generation. With any phenology, the main periods of life of the Siberian silkworm (years, development of caterpillars, etc.) are very extended.

In determining the duration of the development cycle, heat plays a decisive role, i.e. weather and climate in general, as well as timely passage of diapause by caterpillars. It is characteristic that the transition to a one-year development cycle in places with a two-year generation is most often observed during an outbreak of mass reproduction. It is also believed that the one-year development cycle begins if the annual sum of temperatures exceeds 2100 °C. At the sum of temperatures of 1800–1900 °C the generation is two-year, and at 2000 °C it is mixed.

Silkworm flights are observed annually, which is explained by the presence of mixed generations. However, with a pronounced two-year development cycle, flight years occur every other year.

Silkworms damage 20 species of tree species. It appears en masse in different years and is characterized by variable shapes of the gradation curve. Most often, outbreaks of mass reproduction of silkworms occur after two or three dry growing seasons and the accompanying strong spring and autumn forest fires.

In such years, under the influence of a certain way of developing metabolism, the most viable and fertile individuals appear, safely enduring difficult periods of development ( younger ages caterpillars). Forest fires contribute to the proliferation of the pest by burning the forest floor, in which entomophages (telenomus) die. In lowland forests, outbreaks of silkworm numbers are usually preceded by periods of little snow. harsh winters, leading to freezing of entomophages that are less cold-resistant than silkworm caterpillars. Outbreaks occur primarily in forests thinned by logging and fires, near raw material bases with low plant density of different ages and composition. Most often these are overmature and ripe, less often middle-aged pure stands with sparse undergrowth and a slight admixture of deciduous trees.

At the beginning of an outbreak and during periods of depression, the silkworm has a clearly expressed commitment to certain types forests, landforms, phytoclimate and other ecological features of plantings. So, in the flat part Western Siberia The centers of population outbreaks are most often confined to fir, sorrel and green moss forests. In the zone of coniferous-deciduous forests Far East they are associated with mixed cedar and cedar-fir plantations, and in Eastern Siberia their placement is closely related to the topography of mountain forests and the dominance of larch and cedar.

In terms of nutritional value for caterpillars, larch needles are in first place, followed by fir, and cedar needles are only third. Therefore, in larch forests the fertility and reproductive energy of butterflies is the highest, and in cedar forests it is average. In fir forests, caterpillars rapidly develop in an annual cycle, but to the detriment of fertility, which drops to average values. When feeding on spruce and pine needles, individuals quickly become smaller and their fertility and survival rate drop.

Outbreaks of mass reproduction last 7–10 years, of which 4–5 years significant damage is caused to plantings; tree stands denuded by caterpillars dry out and are colonized by stem pests.

The most unstable species in the taiga is fir (Siberian, white-faced), the most stable is larch (Siberian, Dahurian, Sukacheva).

In the first year of severe damage by caterpillars to coniferous trees, the latter are colonized by stem pests only when they are completely defoliated. In subsequent years, their numbers and activity initially increase rapidly, and after 2–4 years a sharp decline begins.

The Siberian silkworm is an enemy of taiga forests, and the losses it causes are comparable to losses from forest fires. The distribution area of ​​the moth extends from the Urals to Primorye, including Mongolia, Sakhalin, the Kuril Islands, part of China, Japan and North Korea.