Svetlana Lapshina

Unexpectedly, almost all of Siberia was covered by silkworms this year. Cedar forests were damaged in Kemerovo region(pests are registered on an area of ​​about 12 hectares), in Irkutsk (about 50 thousand hectares), in the Krasnoyarsk Territory (about 1 million hectares).

– It was the youngest cedar tree. Middle age the trees are 100–120 years old,” sighs the district forester of the Bogashevsky forestry, Alexander Boltovsky, pointing towards the field. – This tree was completely eaten by silkworm caterpillars. In 32 years of work, this is the first time I have seen this.

Instead of a gorgeous green crown, there are only bare branches - not a single needle on the tree. And there are dozens of such cedars...

Caterpillars attack

Two areas of plantings in the Luchanovsky pine forest near the village (total area of ​​almost 18 hectares) were destroyed by the Siberian silkworm in three weeks of August. Local boys, climbing cedar trees for cones, told the forester: “There are some worms crawling up there.” But the experienced Boltovsky was already in the know.

“I walked around these fires ten times and calculated the area affected by the silkworm. The most important thing is to prevent the pest from spreading to next year. In the spring, it is imperative to treat these areas and especially those areas that are adjacent to healthy plantings, explains Alexander Boltovsky.

There are about 5 thousand hectares of cedar forests in the Bogashevsky forestry. Problems have arisen so far only in the vicinity of the village of Luchanovo.

Now the pest has left for the winter. We easily found silkworm caterpillars in the forest floor.

“There are so many of them,” Alexander Boltovsky demonstrates a harmful crop in the palm of his hand. – It seems that the caterpillars have died? Nothing of the kind. Now they are in a state of suspended animation. But this is a cocoon. It will produce an adult Siberian silkworm.

There is a chance that the trees will survive. Because the overeating was one-time and autumn period. And the buds from which the needles grow are still alive.

The silkworm gave the heat

The Siberian silkworm is a common inhabitant of our forests. With low numbers, it does not pose a danger. However, favorable for him weather conditions Last year’s warm winter and long hot summer provoked uncontrolled population growth. As a result, in the Tomsk region, foci of cedar infestation simultaneously broke out in the Bakcharsky, Verkhneketsky, Pervomaisky, Tomsk, Parabelsky, Kolpashevsky, Chainsky, Molchanovsky and Kozhevnikovsky districts.

Siberian silkworm outbreaks most often occur after two or three dry growing seasons. In such years, the most viable and fertile individuals appear, characterized by particular gluttony.

– The area affected by the pest is at least 424 thousand hectares. None of the specialists expected such a rapid development of events,” explains Anton Balaburkin, chief specialist of the forest protection department of the regional forestry department.

But this is not the final figure yet. Surveys in the region will last until the end of December. They are carried out by forest rangers and forest pathologists from the Forest Protection Center. The main task is to find out the boundaries of the outbreak and the number of the pest. Now experts plan to examine the forest in the Teguldet region.

- It's very difficult, but necessary work. It makes it possible to see the whole picture as a whole,” continues Anton Balaburkin.

Experts determine the number of Siberian silkworms by rounding several trees. They count the number of fallen caterpillars and, based on this data, draw conclusions about the threat of overeating. This indicator is necessary for planning actions to eliminate cedar lesions for the next year. If the threat of overeating is 50% or more, special measures must be prescribed. When the silkworm caterpillar stops feeding and goes into the litter, forest pathologists conduct excavations.

– A thousand caterpillars on a tree is not the limit. In some areas of the Bazoi cedar forest of the Kozhevnikovsky district, their number on cedars reached two thousand. And for one hundred percent gorging, even six hundred caterpillars are enough,” comments Anton Balaburkin.

Give for nuts

Almost 450 million rubles are needed to save the cedar forests. It is planned to allocate about 50 million from the regional budget for next year to combat the Siberian silkworm. Therefore, the regional authorities turned to the Federation for support: Governor Sergei Zhvachkin wrote a letter to Rosleskhoz.

– We cannot write off the social significance of cedar forests. Most of them are near villages, that is, they are located close to settlements. And for many local residents, harvesting pine nuts is the main source of income,” emphasized Anton Balaburkin.

The ideal option is to treat the entire affected area. The optimal time for carrying out such work is the first ten days of May. At this time, the caterpillars emerge from the litter, climb into the crown and begin to actively feed. And at this moment it is necessary to strike from the air - to spray with the help of air transport special means.

Siberian silkworms are poisoned using the biological drug “Lepidotsid”. It is harmless to people and animals, including bees.

- IN at the moment we're trying to get on federal level permission to use chemicals struggle. Biological drugs are effective, but they have a very serious limitation - the temperature of use, notes Anton Balaburkin. – “Lepidotsid” acts at an average daily temperature of 18 degrees and above, and here in early May it will be at most plus 10.

The problem is that all Russian chemical products have expired certification periods - they need to be renewed. And this also takes time. IN Soviet years there were more than 20 different products approved for use. Tomsk residents turned to the government with a request to use at least some of them.

The amount of work ahead is very large. But success will be achieved only if everything works out: federal money comes to the region, competitive procedures are successfully completed... At stake is the priceless asset of the region - His Majesty the Siberian cedar.

The Siberian silkworm caterpillar has six instars. Basic nutrition occurs starting from the third age. During the third or fourth period, the caterpillar eats at least 30% of the tree crown, during the fifth or sixth period, everything else. In the Tomsk region there are areas where overeating is 100%.

There is an outbreak in our region mass reproduction the Siberian silkworm was in the mid-1950s. Then the silkworm damaged about 1.5 million hectares of taiga. The northeast of the region was especially affected.

The Siberian silkworm feeds on the needles of almost all coniferous species found within its range. It prefers larch, often damages fir and spruce, and to a lesser extent pine trees - Siberian and Scots.

The development cycle of the Siberian silkworm usually lasts two years.

In the second half of July, the butterfly season begins and lasts about a month. Butterflies don't feed.

The female lays an average of about 300 eggs, placing them one at a time or in groups on the needles in the upper part of the crown.

In the second half of August, caterpillars of the first instar emerge from the eggs, they feed on green needles and in the second or third instar, at the end of September, they go to winter. Caterpillars overwinter in the litter under a cover of moss and a layer of fallen pine needles.

The rise in the crown is observed in May after the snow melts. The caterpillars feed until next autumn and leave for the second wintering at the fifth or sixth age. In the spring, they rise into the crowns again and, after actively feeding, in June they weave a dense gray cocoon, inside which they then pupate. The development of the silkworm in the pupa lasts 3–4 weeks.

Egg. The shape is spherical. Diameter - 2.2 mm. The color of the integument is initially light green with a dark brown dot on one side, but as the egg develops it darkens.

Development

Mating period. Mass flight is observed in mid-July and lasts until the first half of August. Immediately after mating, females begin to lay eggs one at a time or in groups on needles, and during periods of increasing numbers - on dry branches, grass, lichens, forest floor. Up to 200 eggs are observed in one clutch. Maximum fertility is up to 800 eggs.

Egg. Embryonic development lasts 13-15, less often 20-22 days.

Older caterpillars are capable of crawling through treeless spaces in search of food plants and migrating over a distance of up to 1.5 km.

Morphologically related species

In appearance (morphology) the pine cocoon moth (Silkworm) (Dendrolimus pini) is close to the described species. The butterfly's span is 60-80 mm. The color is variable, most often gray-brown. The front ones have a wide sinuous band, the color of which varies from gray-brown to red-brown. On each forewing there is a small semi-lunar white spot. The rear range passes through 40°c. w. According to long-term observations, there is a gradual expansion of the range to the west and partially to the north.

Maliciousness

The Siberian silkworm (cocoon moth) harms more than 20 species of conifers, preferring larch. Caterpillars destroy needles throughout their development, but the greatest damage is caused during the last instars. In a two-year period, this is the time after leaving the second wintering.

In terms of the frequency of outbreaks of mass reproduction and the area of ​​outbreaks, the Siberian silkworm ranks first among the primary pests. Mass reproduction of the Siberian silkworm entails an outbreak of reproduction of secondary pests (longhorned beetles, bark beetles, borers and others).

The spread of the pest is possible not only naturally(movement of caterpillars and butterflies), but also with the help of transport, by transporting forest products - unbarked logs and other timber, forest litter, seedlings and saplings - eggs and cocoons can spread.

Siberian silkworm

cedar silkworm (Dendrolimus sibiricus), a butterfly of the cocoon moth family, dangerous pest coniferous forests. Wingspan up to 90 mm, color gray. Distributed by N. sh. from the shores Pacific Ocean to E. to 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 younger caterpillars with 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 Dictionary Ozhegova. S.I. Ozhegov, N.Yu. Shvedova... ... Ozhegov's Explanatory Dictionary

Cedar silkworm (Dendrolimus sibiricus), butterfly of the family. cocoon worms. 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

The pine silkworm is a voracious caterpillar that can cause irreparable damage not only on a personal plot, but also in large forestry. The insect prefers pine trees, but can feast on cedar and other representatives of the genus coniferous plants. Today there are several, indeed effective techniques, capable of combating the pest and saving trees.

Appearance

The pine silkworm or cocoon moth is a large butterfly and caterpillar. It is a representative of the Lepidoptera order from the cocoon moth family.

The color of the insect is variable, from gray, brown to brown. In general, the color of the butterfly closely resembles pine bark. On the upper wings of all individuals there are brown-red stripes with a jagged black border. And closer to the head there is a white spot on each wing. The body and lower wings are plain.

Males are slightly smaller than females, their wingspan is 7 centimeters, females have 9. Another difference is that females have thread-like whiskers, and males have comb-like whiskers.

Difference between the pine cutworm and the Siberian silkworm

These two types of insects have many characteristic features, and, most importantly, both species eat pine. However pine cutworm prefers young animals and is a nocturnal inhabitant. The color of cutworms is also different: their wings are brownish-green, reddish, that is, they best match the color of young bud sprouts. At the caterpillar stage, the color of the insect is green, with white stripes, of which there are five and one white stripe above the legs. The butterfly's flight begins in the same period as that of the Siberian silkworm.

Geography of distribution

The pine silkworm is present everywhere. In Russia, a huge concentration of insects can be observed along the banks of the Northern Donets, in band burs Western Siberia. In the 50-60s of the last century there were even protracted outbreaks of mass reproduction of the pest. The death of pine trees from insects is periodically observed in the Bryansk and Gomel regions.

The cocoon moth prefers middle-aged plants. In places where it is very humid, it often dies from fungal diseases, so it prefers dry forests.

Reproduction

The butterflies' flight begins in mid-June and ends around mid-August. Already in the middle of the first month of summer, females begin laying eggs. They can be found on the bark of pine trees, branches, and pine needles. One female is capable of laying about 300 eggs, about 50 in one pile.

The development of eggs lasts from 14 to 25 days and already in early August young caterpillars appear, which, having matured, reach 8 centimeters in length. Distinctive feature The cocoon moth at this stage has a reddish tint on the hairline and dark blue stripes on the second and third segments of the body. Thanks to this, perhaps everyone will recognize a pine silkworm in a photo, just as if they saw it in person.

Nutrition and development

Already on the second day from birth, the caterpillar begins to actively eat needles. By mid-autumn, insects descend to the ground and hide under fallen branches and pine needles. Some individuals even burrow into the ground, about 10 centimeters.

Already with the first warming in spring, the caterpillars climb onto pine trees and begin to actively devour them, preferring young shoots. However, the insect is usually found on older trees, from 10 years old. Only by mid-June does the insect turn into a pupa. During this period of time, a huge number of pupae can be observed on the branches. And after about three weeks, butterflies begin to appear.

In most cases, the pine silkworm caterpillar overwinters for one season. But some individuals do not have time to fully develop and winter for two seasons.

Harm

The cocoon moth, like most insects, has certain benefits along with harm. First of all, the insect eats old needles of diseased trees, and only when the population is huge does it move to young trees.

One adult individual is capable of eating 60 needles per day; if you count for the entire period before pupation, you get more than 1 thousand pieces. Naturally, trees simply do not have time to recover if there is a huge population of cocoon moths in the region. During periods of drought, insects are able to consume hectares of forests, because drought is the most favorable factor for reproduction and growth.

An interesting fact is that in the same region, massive outbreaks of population growth can be observed for 5 years in a row.

Danger to humans

Butterflies pose no danger to humans, but with caterpillars the situation is different.

Regular pine and traveling silkworm at the caterpillar stage has hair on which there is toxic substances. The poison is contained in minimal doses and is designed to protect the caterpillar from insects and birds. However, it can also cause trouble for a person. Naturally, you cannot be poisoned by poison from caterpillar hairs, but it greatly irritates the mucous membranes and skin. Therefore, handling the cocoon moth in your hands at the caterpillar stage is strongly not recommended.

Natural enemies

Iridescent flies and tahini flies feast on silkworm eggs. The eggs are consumed by hedgehogs and shrews. Muscardines are fungi that kill silkworms.

Fighting methods

If a small population of pine silkworms is discovered, then this place is isolated from other trees, grooves are dug, thereby preventing the pests from moving to healthy trees. Affected and isolated trees are treated with track glue. If mass infection occurs over large areas, then sanitary treatment with dust is carried out using aircraft.

Toxic belts give good results. The procedure is carried out at the end of March before the caterpillars begin to wake up for the winter. The essence of the treatment is that the plant trunk is treated with dust to a height of approximately 1.2-1.5 meters from the ground.

To additional biological methods The fight against cocoon moths may include additional settlement of natural enemies. Good results can be achieved by introducing the telenomus egg eater. At the same time, telenomus spreads quite quickly; if several individuals of the pest are placed on one clutch, then literally in a couple of days the pest will already spread 300 meters.

In some cases, ants from the genus Forminka are settled, which are also natural enemy silkworm. The ant is under protection, so its artificial resettlement is justified.

In garden plots, you can treat pine trees with dust, or use special products, for example, Karbofos.

Forest pests in the Baikal Nature Reserve.
Siberian silkworm

Research abstract

Pine cocoon moth: 1 – male; 2 – female; 3 – caterpillar; 4 – cocoon

Lake Baikal... Millions of people know it today. There is no other lake on earth like the sacred Baikal glorified in legends and songs. Everything about it is unique - water, vegetation, rocky shores and the majestic spurs of the ridges framing it. In order to preserve this priceless gift of nature for our descendants, we must take care of everything connected with Baikal.

In 1969, in the central part of the Khamar-Daban ridge, the Baikal state reserve total area 166 thousand hectares, later received the status biosphere reserve with inclusion in the international network of protected areas. The main objectives of its activities are the study of natural processes, the restoration of natural complexes of the southern coast of Lake Baikal and the enrichment of hunting and commercial species in the lands adjacent to the lake.

The territory of the reserve is asymmetrical due to the Khamar-Daban ridge stretching from west to east. Maximum height in its central part it is about 2300 m above sea level. Average temperature air on the coast of Lake Baikal in July is +14 °C, in January –17 °C at average annual temperature–0.7 °C.

Reserved region It’s impossible to imagine without butterflies fluttering over the flowers, captivating with their unique beauty. Among the butterflies there are species listed in the Red Book, such as Apollo and swallowtail. Bluebirds, wrens, and nigellas are common in meadows. Hawk moths and she-bears are found under the canopy of birch groves. From dusk until dawn, numerous representatives of noctuid moths, graceful moths, and corydalis gather at light sources.

Insects are the most numerous group of animals in the reserve. They can be found in the air, on the ground, in water, and in soil. Dangerous pests of the tree stand include the Siberian silkworm, willow moth, and gypsy moth. Their mass reproduction can lead to partial or complete drying out of forests.

In 1869, a scientist from Massachusetts, Truvello, brought Siberian silkworm eggs to the United States ( Dendrolimus sibirecum). several tracks were lost. After some time, this led to a massive proliferation of silkworms, whose caterpillars denuded forests and gardens in Massachusetts, and in 1944, despite the fight against them, they occupied all of New England.

The first information about the Siberian silkworm in the forests of the Baikal region was published by K.A. Kazansky in 1928. According to D.N. Frolov, in 1948, in the Kultuk forestry alone, the Siberian silkworm led to the drying out of 24,670 hectares of valuable cedar plantations. Outbreaks of mass reproduction of the Siberian silkworm were also observed in other areas of the Baikal basin.

Siberian silkworm – large butterfly with a wingspan of 60–80 mm in females and 40–60 mm in males. Color varies from light yellowish brown or light gray to almost black. The forewings are intersected by three darker stripes. There is a large white spot in the middle of each wing; the hind wings are the same color.

A revision of the genus showed that the Siberian silkworm is a subspecies of the large coniferous silkworm ( Dendrolimus superans Butl). Since the Siberian silkworm can only be recognized as a subspecies, its ecological and morphological forms should be considered tribes.

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.

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, and forest litter. 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.

The eggs are almost spherical in shape, up to 2 mm in diameter, at first bluish-green in color 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 go to their second winter. In May-June of the following year, adult caterpillars feed intensively, causing the 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. Mass migration of butterflies occurs 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 in masses in different years and is characterized by variable forms 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 the 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 others environmental features plantings. Thus, in the flat part of Western Siberia, outbreaks of abundance 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 come first, followed by fir, and cedar needles take only third place. 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, Daurian, 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, Kuril Islands, parts of China, Japan and North Korea. Supervision of the Siberian silkworm should be concentrated in places where silkworms are most actively breeding and should be carried out especially carefully after dry periods, which favor an increase in numbers. It must include aerial reconnaissance areas with increasing numbers of the pest and ground forest pathological surveys, as well as recording caterpillars and flying butterflies.

Active foci of mass reproduction of the Siberian silkworm were first identified in northern regions Buryatia in larch, larch-pine plantations of the Angarsk forestry enterprise. The area of ​​focal distribution of silkworms on the northeastern coast of Lake Baikal (Baikal, Nizhneangarsk and Florikhinsk groups of outbreaks), according to the forest pathological survey of 1980, amounted to over 100 thousand hectares. Increased numbers of silkworms in 1981–1986. was also observed in the forests of the southern regions of Buryatia (Dzhidinsky, Kyakhtinsky, Bichursky forestry enterprises).

The unique climatic and forest-ecological conditions of the Baikal forests determine the regional features of the ecology and biology of this pest. Everywhere, the development of silkworms proceeds on a two-year cycle; in the forests of Khamar-Daban, entomologist Rozhkov noted a three-year generation. The development of silkworms according to one-year generation is possible only in larch forests growing in the zone of Southern Transbaikalia. The Baikal and Transbaikal populations of the Siberian silkworm are characterized by the simultaneous existence of two generations, each of which develops in a two-year cycle. The level and ratio of the numbers of these generations may vary, but most often one of the generations dominates. In this regard, the mass migration of Siberian silkworm butterflies in some populations is observed in even years, and in other populations in odd years.

Thus, in terms of the frequency of outbreaks of mass reproduction and the area of ​​focal distribution, the Siberian silkworm is the most dangerous pest of coniferous forests in the Baikal basin.

In the Baikal Nature Reserve, entomologist N.A. monitors the Siberian silkworm. Belova.

Literature

Mikhalkin K.F. Baikal Nature Reserve.

Fauna of the forests of the Lake Baikal basin. – USSR Academy of Sciences, Siberian Branch, Forest Institute named after V.N. Sukacheva.

Atlas-identifier of insects.