The Siberian silkworm is a large butterfly with a wingspan of up to 80 mm (photo below). Males differ from females in their smaller size and the presence of comb-like antennae. The color is yellowish-brown, brown, gray, black. There are patterns and light spots on the front pair of wings. The hind wings are a single color. A photo of the Siberian silkworm at the adult stage is presented below.

The eggs are spherical, up to 2 mm in size (photo below). Initially, the eggs are bluish-green in color, gradually changing color to brown.

Note!

The color may vary depending on where the female laid the egg - on the bark of trees, stems, leaves. Siberian silkworm eggs are located in groups or one at a time. The photo can be seen below. One clutch can contain about 200 pieces.

Siberian silkworm caterpillars are born miniature - about 2 mm. They eat well and grow quickly. At the last stage of development, the body length of the larvae is 70 mm. The color is variable - from green to brown and almost black. You can see stripes on the body purple, spots. Caterpillars go through 4 molts and constantly increase in size. Photos of the butterfly's offspring can be seen below.

At the end of development, the Siberian silkworm caterpillar turns into a pupa. The cocoon is formed from a silk thread, which it produces itself. It clings with its paws to the bark of trees, stems, leaves, and freezes. Cocoon size up to 40 mm. Initially, the covers are light, then they acquire a brown tint, black, which is clearly visible in the photo of the Siberian silkworm cocoon.

Features of development

The butterfly flight begins in the second half of July and lasts about a month. Mating occurs on the fly. The male dies soon after fertilization, the female looks for a favorable place to lay eggs. Attaches them to tree bark and leaves using a special sticky substance that is released along with the eggs.

The larvae inside lasts up to 22 days, with favorable conditions The young offspring of the Siberian silkworm appear already on the 13th day. First instar caterpillars actively feed on needles and grow quickly. In the period from August to September they increase significantly in size, and the chitinous cover thickens. The cycle in the photo. At the end of September, the caterpillars crawl under the bark, forest floor, remain to spend the winter.

With the onset of warmth - in May, the larvae rise to the crowns, where they live and feed throughout the warm season. The caterpillars undergo the second wintering at the fifth or sixth age. They continue to develop in May and pupate by the end of June. The development of a butterfly in a cocoon lasts about a month. Externally - a motionless creature, inside - the most complex processes of transformation take place. Young butterflies appear in early September. Their task is to find a secluded place for wintering. Below is a photo of the young.

Note!

Development occurs over 2-3 years, while butterflies at the imago stage live no more than a month and do not feed on anything. Energy reserves are enough to lay about 300 eggs at a time.

Sabotage

It’s not hard to guess why the Siberian silkworm is dangerous. Due to the fact that the development of the larvae stretches over several years, and every spring they rise into the crowns, there is a risk of weakening the tree.

Butterflies disperse their numerous offspring throughout different plants. In July, mass infection covers several million hectares of forest. This causes enormous damage to forestry. The natural enemies of the Siberian silkworm are borers, bark beetles, and longhorned beetles. The photo can be seen below. Since bark beetles also cause damage to coniferous plantations, the scale of the pest increases several times more. Birds of prey eat insects.

In the mid-90s, the fight against Siberian silkworm larvae lasted 4 years. Then about 600 thousand hectares of forest area suffered from the pest invasion. Cedar trees, which were of great value to local residents, died.

Over the past 100 years, 9 outbreaks of mass pest control of silkworm caterpillars have been observed in Siberia. It was possible to stop the reproduction thanks to the use of modern insecticides. and other plants are taken constantly, if not to destroy caterpillars, then to prevent their appearance. Photo mass destruction plants are presented below.

Interesting!

Sericulture is especially developed in China. Natural silk, which is obtained from threads, is highly valued. Insects are specially bred on mulberries, providing everything necessary conditions existence. The cocoons are collected without allowing the butterflies to be born. The length of the threads of one cocoon is about 900 m. Butterflies lead a sedentary lifestyle and practically do not fly. The larvae are not dangerous to surrounding plants.

Fighting methods

Caterpillars damage larch, oak, beech, birch, pine, spruce, aspen, fir, cedar, and maple. prefers deciduous trees, but does not disdain conifers. The first instar larvae feed during the day, and as they grow older they switch to a hidden lifestyle - they crawl out of their shelters at night.

Main control measures:

• Collection and destruction of ovipositions. In small areas, young trees are scraped off by hand, trampled underfoot, or thrown into the fire. Below are photos of infected plants.
• Late autumn or early spring eggs are destroyed using petroleum products - gasoline, kerosene, motor oil. However, you should always remember that these are flammable substances; if used incorrectly, the risk of a massive fire increases.
• Against the larvae, adhesive rings are used, which are placed at a level of 1.5-2 m above the ground surface, which does not allow pests to reach the crown.
• In small areas, caterpillars are collected by hand and then destroyed in any way.
• Most effective method– insecticidal substances. Spray crowns and tree trunks. Treatment can be carried out in early spring before or after the trees bloom. The effect of the poison lasts for 20-45 days. Repeated processing is carried out as necessary.

Every autumn and spring, you need to carefully inspect the bark of trees for the presence of eggs and larvae, and coat the trunks with a solution of lime and chalk. Life cycle The insect's life spans several years, so there is always a threat of infection. Spread to other trees occurs either in early spring or late autumn. You should carefully examine the pest in the photo so that you can respond to the problem in a timely manner.

Siberian silkworm

cedar silkworm (Dendrolimus sibiricus), a butterfly of the cocoon moth family, a dangerous pest coniferous forests. Wingspan up to 90 mm, color gray. Distributed by N. sh. from the shores of the Pacific Ocean in the east to the Southern Urals in the west and from Yakutia in the north to Northern China in the south. Damages larch, fir, cedar, rarely spruce, and pine. The first butterflies appear at the end of June, the mass flight begins, as a rule, in mid-July and ends in the 1st half of August. S. sh. has a two-year or one-year generation. With a two-year generation, the number of caterpillar ages is 7-8, with a one-year generation - 5-6. The bulk of caterpillars overwinter on the forest floor in the 3rd instar (in larch plantations, more often in the 2nd instar). After the snow cover melts, they feed on pine needles, eating them entirely. Sometimes buds and even young cones are damaged. Eating needles is one of the reasons for the mass reproduction of stem pests (especially longhorned beetles), which damage plantings and lead to their death. Regulates the number of S. sh. its common natural enemy is the telenomus ichneumon. Mass death of caterpillars of S. sh. usually occurs as a result of epizootics caused by bacteria.

Control measures: spraying foci of S. sh. during the development of caterpillars younger ages insecticides from airplanes. See also Art. Forest pests.

Lit.: Forest entomology, M., 1965.

N. N. Khromtsov.

Great Soviet Encyclopedia. - M.: Soviet Encyclopedia. 1969-1978 .

See what "Siberian silkworm" is in other dictionaries:

Butterfly of the cocoon moth family; pest of coniferous trees in Siberia and the Far East. The wings are gray. The caterpillars feed on needles, buds, young cones... Big Encyclopedic Dictionary

SIBERIAN SILKWORTH, a butterfly of the cocoon moth family; pest of coniferous trees in Siberia and the Far East. The wings are gray. The caterpillars feed on needles, buds, young cones... Encyclopedic Dictionary

SILKWORTH, huh, husband. 1. A butterfly, a caterpillar in a swarm spins cocoons that are used to make silk (in 1 value). Mulberry sh. 2. Butterfly, caterpillar and swarm is a forest pest. Sibirsky highway Sosnovy highway Ozhegov's explanatory dictionary. S.I. Ozhegov, N.Yu. Shvedova... ... Ozhegov's Explanatory Dictionary

Cedar silkworm (Dendrolimus sibiricus), butterfly of the family. cocoonworms. Wingspan up to 90 mm. Butterflies and caterpillars are similar to those of the pine cocoon moth. In Siberia, in the D. East, in the North. Mongolia, North China, Korea, Japan. Mass flight in the 2nd... Biological encyclopedic dictionary

A; m. 1. A butterfly whose caterpillar weaves cocoons that are used to make silk (1 digit). Mulberry sh. 2. A butterfly whose caterpillar is a dangerous pest of tree plantations. Unpaired sh. Kedrovy sh. Sibirsky sh… Encyclopedic Dictionary

silkworm- A; m. 1) a butterfly whose caterpillar weaves cocoons that are used to make silk 1) Mulberry silkworm/d. 2) A butterfly whose caterpillar is a dangerous pest of tree plantations. Gypsy moth/d. Cedar silkworm/d. Siberian silkworm/d... Dictionary of many expressions

Siberian silkworm (cocoon moth) – Dendrolimus sibiricus Tschetw

Damages

Silkworm caterpillars in different parts of its wide range they feed on the needles of various coniferous tree species, giving preference to the needles of larch (Daurian, Sakhalin, Siberian, Sukachev), fir (Siberian, Sakhalin and whitebark) and cedar (Siberian and Korean). Less willingly, usually when growing together, the caterpillars feed on the needles of spruce (Siberian and Ayan), Scots pine and dwarf cedar.

Maliciousness

One of the most harmful types of pine-eating pests.

Spreading

The Siberian silkworm is widespread in the forest and forest-steppe zones of Siberia - from the Urals to Sakhalin, Kunashir and Iturup inclusive ( Kuril Islands). Northern border distribution - from White Sea to Penzhinskaya Bay - coincides with the Arctic Circle, not reaching it in the European part of Russia and east of 145°. The southern limit of distribution in the European part of Russia and in Western Siberia coincides with the southern border of the distribution of Sukachev larch and Siberian larch; further to the east it passes into the northwestern regions of China, Mongolia, the northeastern regions of China and Korea.

Preferred stations

Reservations and primary foci of silkworms are confined to plantings that are more well heated and aerated, with drier growth conditions or with well-drained soils, average density (0.4 - 0.7) or to their outskirts, edges, open spaces, more often to clean plantings , older age classes belonging to groups of drier or fresher forest types (green mosses, forbs, etc.). They are located: in the flat taiga - along the crests of the relief, in low mountains(up to 500 m altitude) - on the plateau and along the slopes, in the lower and middle mountain taiga more high mountains, located in northern or humid areas - along the slopes of southern points, and in southern or dry areas - along the slopes of other points. In plantations disturbed by logging, especially clear-cutting, forced-selective and other unmanaged logging, xerophytization of plantings occurs, which favors the constant nesting of silkworms and the transformation of plantings into primary foci during droughts. The same xerophytization of plantings and destruction of natural biogeocenoses in them occurs, especially with intensive grazing of livestock in them, in the vicinity of large settlements

Generation

Everywhere in the silkworm habitat in our country, a 2-year generation has been registered. Nowhere has the annual generation been established as constant for a given area. However, in warm years, in which the growing season is extended. An earlier period, starting earlier in the spring and lasting longer late autumn, conditions are created that are conducive to feeding and faster development of the silkworm. The life of its butterflies proceeds earlier, the laid eggs develop faster, the emerging caterpillars feed longer, go to winter at an older age, next year they emerge from winter earlier and manage to complete their development completely within a year. Since the development of the outbreak is confined to a period of warmer, sunny and drier years, in these same years a transition in the development of silkworms in Western Siberia from a 2-year to a one-year cycle was noted. It should be emphasized that such a transition was more often observed in the fir race, which is distinguished by its smaller size and fewer instars during the caterpillar stage.

P. P. Okunev (1961) suggests that in areas located north of the July isotherm +18°, the Siberian silkworm develops on a 2-year cycle. In areas south of the July isotherm of +20°, development proceeds according to an annual cycle. In areas located within the boundaries between the named isotherms, development proceeds according to a variable cycle: in inter-outbreak years, as colder ones, according to a 2-year cycle, and in outbreak years, with a colder cycle. warm weather- according to the annual cycle.

Population structure. With a 2-year generation, two tribes of Siberian silkworms can exist in parallel in the same area, one of which flies in odd years, and the second in even years. The number of these tribes and its ratio may be different, which has great value for surveillance and control.

Diagnostic signs

Siberian silkworm eggs

Siberian silkworm caterpillar

Butterflies

especially during periods of mass reproduction, they are so diverse in color and size that it is difficult to pick a pair of butterflies that are completely similar to each other. Females have short combed antennae and a thick body; their wingspan is from 6 to 10 cm. Males have clearly combed antennae and a more slender body; their wingspan is from 4 to 7.5 cm. The forewings of both sexes are light brown or light gray to almost black. Three jagged stripes run across them; one along the outer edge of the snout, the second near its middle and the third closer to its base. In close proximity to the dark stripes, often along the outer edge of the wing, there are whitish stripes consisting of semilunar spots and strokes. The field between the main and median stripes is often darker in color. Sometimes the main and median stripes are weakly expressed or even completely absent. Near the middle of the main stripe there is a semi-lunar white spot, which is always present in butterflies. The hind wings are light brown without a pattern. Below, both pairs of wings are brown, and there is one wide dark brown curved band running along them. The head and chest are colored similar to the front wings, the abdomen is similar to the hind wings.

Testicles

spherical, 2.0×1.5 mm in size, with a dark dot at the apex. Freshly laid eggs are bluish-green, then turn grey. They are smaller and somewhat lighter than pine silkworm, are deposited in irregular piles from several to 100 pieces and mainly on needles, twigs, twigs, bark of branches and trunks. When the caterpillar emerges from the egg, it eats part of the shell.

Caterpillars

up to 11 cm long, varied in color - from gray to almost black. On the meso- and metanotum there are transverse bands of steel-blue burning hairs that open wide when the caterpillar raises the front part of the body and bends its head (threat pose). On the next seven abdominal tergites there are dark horseshoe-shaped spots. The dorsal side and spots on the sides are covered with silver-white spear-shaped scales, developed to varying degrees in individuals. On the sides of the body, areas of skin are ocher- yellow, sometimes forming an almost continuous strip. The body is covered with hairs, the longest and densest on its sides and in front on the prothorax. The head is round, matte, dark brown. Ventral side between legs with yellowish-brown or orange spots, not forming a continuous stripe.

The stool of the caterpillars is cylindrical, with six longitudinal and two transverse grooves, very similar to the stool of the pine silkworm. The pieces of needles in it are hardly noticeable.

doll

up to 5 cm long, pitch-brown to black. Cremaster in the form of a transverse convex plate, densely covered with very small rufous hooked and simple setae. The last segments have short and sparse hairs. The pupa rests in a parchment-like, brownish or dirty-gray cocoon, into which tufts of blue, burning caterpillar hairs are woven, giving the cocoon its burning properties. Cocoons are located on branches, between needles, on trunks.

At the beginning of mass reproduction, dark-colored individuals of butterflies and caterpillars dominate, as in other mass needle- and leaf-eating insects.

Races

The question of the races of the Siberian silkworm remains unresolved. But, apparently, three races can be distinguished: larch, cedar and fir. In the process of the historical development of the species, these races not only adapted to feeding on the needles of the corresponding tree species, but also to the entire complex of forest-ecological conditions created by these species in forest stands. The named races of silkworms differ from each other in different amplitudes of size and weight at different stages of development, the number of caterpillar molts, speed of development and other characteristics. The names of these races are left here for ease of presentation.

Siberian silkworm caterpillars overwintering in the litter

Siberian silkworm cocoons

Complete consumption of Dahurian larch needles by Siberian silkworms

Phenology

First year of development

years of butterflies – June (3), July (1-3), August (1); eggs – June (3), July (1-3), August (1-3); caterpillars – July (2.3), August – March (1-3);

Second year of development

caterpillars – April – March (1-3);

Third year of development

caterpillars April – June (1-3), July (1); pupae – June, July (1-3); years of butterflies - June (3), July (1-3), August (1).

Note: ten days of the month are indicated in brackets

With one-year development, the second year falls out of the scheme, when the silkworm remains in the caterpillar stage throughout the entire growing season. On the contrary, when development is delayed to 3 years, the silkworm remains in the caterpillar stage not only during the second, but also the third growing season and completes development in the first half of the fourth growing season. Caterpillars that produce males molt from four to six times during development, and those that produce females molt from five to seven times; respectively, males have from five to seven, and females from six to eight instars.

Caterpillars developing on fir (S.S. Prozorov, 1952) have the following head width in mm: 1.0; 1.5; 2.0; 2.5; 3.5-4.0; 4.5-5.0, respectively, from the first to the sixth instars.

Caterpillars developing on cedar or larch (V. G. Vasiliev, 1940) have the following head width in mm: 0.9-l.0; 1.4-1.6; 1.8-2.2; 2.5-3.2; 3.5-4.2; 4.5-5.2; 5.5-6.2; 6.5-7.2, respectively, from the first to the eighth ages.

From the above it follows that the difference in the width of the head of the caterpillars that fed various breeds, within individual instars is almost absent, but the number of instars in caterpillars fed on fir is 6, in caterpillars fed on cedar - 7, fed on larch - 8. When feeding on larch, caterpillars reach their largest sizes and produce the most well-fed and fertile individuals (pupae up to b grams and butterflies laying up to 826 eggs). However, caterpillars of the larch race, with a lack of food, are able to complete their development at the V (males) and VI (females) instars. But even in this case, they produce heavier pupae and fertile butterflies compared to the cedar and fir races.

During the period of their development, caterpillars of the fir race eat 46.5 g of needles (7185 needles), and 95% of it is consumed in the 5th and 6th instars (S.S. Prozorov, 1952). For other breeds, feed standards remain unstudied.

On the question of the sum of effective temperatures required for full development silkworm, there are disagreements in the literature: S. S. Prozorov (1952) defines it at 2032°, P. P. Okunev (1955) at 1300 - 1500°, Yu. P. Kondakov (1957) at 1200 - 1250° . This issue needs further research.

Siberian silkworm caterpillars are cold-resistant. This gives them the opportunity to leave for the winter late, at temperatures close to zero, and to rise early into the crowns after wintering, following the melting of the snow. However, with sudden and sharp drops in temperature (below -10°), the first instar caterpillars may die en masse. They also die in harsh winters with little snow in their wintering areas. With age, the cold resistance of caterpillars increases, therefore, the chances of their death from frost decrease. In humid wintering conditions and rainy weather, fungal and other diseases spread among the caterpillars, often leading to mass death. This explains the fact that in damp honeydews no centers of mass reproduction of silkworms are created, and the outbreak that has begun subsides under the influence of rainy and cool weather.

Death of dark coniferous forests from complete devouring by Siberian silkworms

Duration of the outbreak

Conflicting opinions exist in the literature about the duration of outbreaks. The development of an outbreak in the same planting (focus) with a 2-year generation is possible within 14 years, and with a one-year generation - within 7 years. An outbreak that develops with a changing generation duration may have an intermediate duration between these deadlines, i.e., when one part of the generations during the outbreak period develops on a 2-year cycle, and the other on a one-year cycle. In the literature you can find reports of shorter-term outbreaks - within 4 - 6 years.

Reconnaissance surveillance

When organizing surveillance, republics, territories and regions in which outbreaks of mass reproduction of the Siberian silkworm have been observed or may be observed can be divided into two halves by a line running through Sverdlovsk - Tyumen - Kolpashevo - Yeniseisk - Nizhne-Angarsk - Kumora-Bambuika - Sredny Kalar - Stanovoy Ridge to the Sea of ​​Okhotsk. North of this line, outbreaks are possible but have rarely been observed. To the south of it, to the border of distribution of larch, cedar, fir and spruce forests, outbreaks of mass reproduction of the Siberian silkworm were observed most often. The southern half includes forests on the islands of Sakhalin, Kunashir and Iturup. In the forests of the northern half, systematic supervision may not be carried out. When a period of intense drought occurs, which also affects these forests, it is necessary to carry out control aerial surveys in them in the appropriate years with ground verification of the emerging foci.

The forests located in the southern half of the forestry enterprises or timber industry enterprises and their constituent forests can be divided into three groups: those located in high mountains or wetlands, in which outbreaks of mass reproduction of the Siberian silkworm are not observed; located in sparsely populated areas and in mid-mountain zones, in which outbreaks of silkworms are observed sporadically; located in populated areas of the southern part of the taiga zone, forest-steppe and steppe, as well as in the lower mountain zones, in which outbreaks of mass reproduction were observed most often.

carried out on the verge of two generations, i.e. annually in the presence of two generations, a silkworm or a mixed development cycle, or in even or odd years in the presence of one generation with a 2-year development cycle.

Detailed supervision

According to the outbreak phases, the weight of pupae and the fertility of butterflies change within the following limits.

In the first and second phases of the outbreak Weight Limit pupae in the larch race are 5.5 - 6.0 grams, in the cedar and fir races - 3.8 - 4.2 g; The fertility of butterflies in the larch race is 650 - 750 eggs, in the cedar and fir races - 400 - 460 eggs. The average indicators are respectively: 4.0 – 5.0 g; 2.8 – 3.3 g; 440 – 580 pcs.; 250 – 330 pcs.

In the third phase of the outbreak average weight pupae in the larch race are 2.5 - 3.0 grams, in the cedar and fir races - 2.0 - 2.4 g; The fertility of butterflies in the larch race is 220 - 380 eggs, in the cedar and fir races - 150 - 200 eggs.

In the fourth phase of the outbreak, the average values ​​are respectively: 1.4 - 1.8 g, 1.5 - 1.8 g, 70 - 120 pcs., 80 - 120 pcs. The minimum indicators are: 1.0 g, 0.8 g, 25 pcs., 5 pcs.

When the first drought occurs in areas with an annual or variable development cycle of the Siberian silkworm, supervision should be strengthened and expanded to the rest of the registered reservations. If there is a repeat drought, a detailed examination of the same reservations, as well as similar plantings, should be carried out. The transition from a 2-year development cycle to a one-year one in areas with a variable development cycle of the Siberian silkworm should itself be perceived as a signal of the need to strengthen and expand supervision. In areas with a 2-year development cycle, surveillance is strengthened and expanded after repeated drought or when ongoing surveillance provides clear evidence of an outbreak.

Repeated drought and indicators obtained during surveillance indicating the beginning of an outbreak should be taken as a signal that it is necessary to conduct control surveys in the above-mentioned second group of forests. Finally, the results of surveillance of other forest pests and even pests should be taken as a signal about the need to strengthen and expand surveillance. agriculture, since droughts initiate the development of outbreaks of many pests. In this regard, for areas with an annual or variable development cycle, supervision of double-generation pests (for example, common and other pine sawflies) is important, since their outbreak occurs 1.5 years earlier than pests with annual generation. In areas with a 2-year development cycle of the Siberian silkworm, mass reproduction of many forest pests with an annual generation, outbreaks of which, generated by the same drought, develop faster, can be perceived as alarms. Such alarm pests include the gypsy moth, ancient, larch and willow moths, larch and pine moths, pine silkworms, larch moths, polyflowers, hawthorn, and in the forest-steppe - locust moths (Siberian moth). Outbreaks of mass reproduction of the gypsy moth and the larch moth do not only occur in tandem. The primary centers of their mass reproduction are formed in similar, and often even in the same larch plantings (Yu. P. Kondakov, 1959).

In plantations affected by ground fires, it is necessary to carry out appropriate methods of supervision over the reproduction of silkworms in the first 3 - 4 years in areas with annual or variable generations, or in the first 6 - 8 years in areas with 2-year generation, even regardless of droughts, since fires can cause local outbreaks that can grow into larger outbreaks during dry periods.

Control measures

Spraying plantings with insecticides in the spring, within 1-2 weeks after the overwintered caterpillars rise into the crowns, or at the end of summer - against young caterpillars.

- a large-sized butterfly with inconspicuous wing colors; the insect belongs to the cocoon moth family. Females are larger than males: the wingspan is 6-8 cm, which is one and a half to two times the wingspan of males. The yellowish-brown or light gray color of the wings allows insects to skillfully camouflage themselves on the bark of trees and serves as protection.

Spreading

Widely distributed throughout Russia, its habitat is limited to the Ural, West Siberian, East Siberian and Far Eastern regions. It is in the territory of Siberia and the Far East that the Siberian silkworm has quarantine significance, as it is the worst pest of coniferous trees. Experts note that in recent years the population is actively moving to the west of Russia.

The threat to conifers comes not from the butterfly itself, but from its caterpillars. Siberian silkworm caterpillars hatched from eggs easily acclimatize, are hardy and very voracious.

Life cycle

An adult butterfly lays eggs on the branches of coniferous trees, usually larch, fir and spruce. On average, each female lays up to 300 eggs per season, some sources indicate that maximum quantity up to 800 eggs laid by one female. The greenish-blue egg is round in shape and measures about 2 mm. One clutch can contain from 10 to 100 eggs.

Emerging from eggs are brown or brown caterpillars they immediately begin to actively feed on the tender needles of the trees. On average, the length of insects is 5-7 cm. Moving from the bottom of the crown to the very top, the voracious larvae leave behind only gnawed branches, which has a detrimental effect on the health of the trees. After the silkworm's work, weakened trees become prey for longhorned beetles and die completely.

In order to develop into a butterfly, the caterpillar must survive two overwintering periods, feeding vigorously during the spring and summer (May to mid-August). Entomologists distinguish 6-8 instars of the caterpillar, during which it goes through 5-7 molts. The greatest damage to trees is caused by caterpillars that have survived the second winter; it is at this time that they absorb 95% of the needles necessary to complete the development cycle. In June, the larva pupates and after three to four weeks, a Siberian silkworm butterfly emerges from a large gray cocoon (28–30 cm) capable of continuing reproduction.

Natural enemies

Like other insects, the Siberian silkworm has its own natural enemies: ichneumon flies, tahini flies or hedgehog flies, and egg-eating ichneumon flies. Especially active participation Braconids and Trichogramma are used in regulating the number of agricultural pests. Trichogramma lay their young (up to four eggs) directly into the silkworm eggs. Tachins are also entomophagous insects, but they lay eggs in the body of an adult insect, which leads to its gradual death.

In some countries, these natural enemies of the silkworm are artificially acclimatized specifically in order to control the population of the latter.

In addition to these insects, the cuckoo, woodpecker, nutcracker, tit and others feed on caterpillars and adult insects of the Siberian silkworm insectivorous birds. Fungal infections also affect the development of insects.

Pest danger

The danger of the species is that the insect can increase the population several hundred times after going through a two-year development cycle. In Siberia and the Far East, millions of hectares of healthy coniferous forest were lost due to the harmful activities of insects. Even natural enemies cannot cope with its invasion.

Gnawed needles cannot lead to the death of a healthy and strong tree, but it seriously weakens it, making it easy prey for wood pests. Bark beetles and longhorned beetles select weak trees and use them to lay offspring in the subcortical layer, after which the beetle larvae eat the tree from the inside. Thus, the insects that have taken over the baton completely destroy the forest, turning it into dead dead wood, which is not suitable for serious construction work. Renewing forests in ruined areas will take at least a hundred years.

To ensure that the problem with the Siberian silkworm does not grow to global proportions, it is necessary to combat the dangerous pest.

Prevention of spread

Measures to combat the Siberian silkworm can be different: some are aimed at stopping the widespread spread, others lead to a decrease in the population. Rosselkhoznadzor recommended introducing strict rules for phytosanitary control over timber exported from quarantine areas.

Phytosanitary restrictions include the following measures:

• Disinfection and debarking of conifers before transportation;
• An accompanying certificate confirming processing is required for the cargo.

These measures should help prevent the expansion of pests into uninfested regions.

Fighting the Siberian silkworm

Mechanical methods of extermination (collecting caterpillars and pupae, removing infected needles) of the pest turn out to be of little effectiveness, since the pest's foci are usually located in the remote taiga. Reveal hazardous areas aerial photography or careful visual inspection terrain. The area with bare coniferous trees is marked on the map and, if the area is large, the area is disinfested.

To destroy the Siberian silkworm in heavily infested areas, it is necessary to resort to insecticides. Chemical treatment of conifers leads to massive death of caterpillars and butterflies. For this purpose, insecticide is sprayed from an airplane onto the infected area.

When performing disinsection, one should take into account the biology of the species and perform it twice a year: in the spring to destroy overwintered caterpillars, at the end of summer to destroy young ones preparing for wintering.

There are biological and chemical insecticides against the pest. Among biological agents, lepidocide can be distinguished, which is successfully used to combat caterpillars of harmful insects in parks and squares, in agriculture and forestry. The protein toxin contained in lepidocide causes paralysis of the gastrointestinal tract in the caterpillars, they stop experiencing hunger and die from exhaustion. The drug also affects adults: butterflies cannot tolerate the smell of this drug, so their age decreases, and after it the number of eggs laid decreases.

Siberian silkworm - a threat to the coniferous forest

It is possible to cope with the worst pest of coniferous species only with the help of carefully organized detailed supervision and compliance with all sanitary treatment requirements. The fact that it is quite difficult to achieve real results in the destruction of insects of this species is evidenced by the dead forests of Siberia and the Far East.

Territories in need of special attention supervisory organizations:

• Areas that have experienced drought;
• Area affected by fires.

The experience of past years shows that it was in such regions, weakened by fires or climatic reasons, that the silkworm population began to grow, often developing into huge foci of infection.

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. A distinctive feature of these insects is the 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 with the help of 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 are round in 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 of gypsy that 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 a new territory, active feeding begins. Young caterpillars eat during the 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 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. The optimal temperature for insect growth is +20-25; if it drops to +10, development stops. Male caterpillars go through 5 larval stages to the imago (adult) stage, 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, 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 as various types depending on where you live and what you eat. 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 the gypsy moth, 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 marching silkworms– oak and pine.

Pine cocoon moth

Insects are common in coniferous forests 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 can accelerate to an annual 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 taking a 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 on its abdomen. 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 vehicles, 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, a tedious procedure that can be done in small areas. An effective way– 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 gardens and forests. At the beginning of spring, trees are treated with Chlorophos, Metaphos, as well as organophosphorus compounds.