With the onset of May, a wonderful time begins in Russia, when cities dress up with bright greenery, the air is filled with the delicate aroma of blooming apple trees and bird cherry trees, and summer cottages Gardeners are preparing their pets for the autumn harvest. But it happens that trees are favored by various pests and people have to fight with them for the safety of green spaces. One such invader is the ermine moth. The insect has a number characteristic features, each of which must be taken into account in the process of combating it.
general description
The term “ermine moth” is the name given by biologists to the family of lepidopteran moths. It includes about 600 species of different insects. Their sizes are small: the wingspan is from six to twenty-eight millimeters. Such organisms live mainly in the tropics, but some species are also found in Russia.
Representatives of this family feed mainly on plants. Sometimes they can eat roots, more often leaves. Caterpillars settle on the stems and leaves of trees, gradually entangling them with cobwebs. In this way, social nests are created, where insects pupate one at a time or by gluing several cocoons together. Several hundred caterpillars can live on one tree. Plants often cannot cope with so many residents and die. Feeding on a certain type of plant, the moth harms forestry and agriculture.
Common types
About ten species of ermine moth can be found in Russia and neighboring countries. The greatest damage to forests and gardens is caused by insects that “specialize” on apple trees and bird cherry trees.
Apple ermine moth is found in the British Isles, Sweden and Finland, Siberia, as well as in Korea, Japan, in some areas of Canada and the USA. The caterpillars of this moth, dark yellow in color with black legs and spots, are also called "May worm" in some areas.
The bird cherry ermine moth lives over a vast territory from the Caucasus to China. As in the case of the apple tree pest, it is very difficult to combat this insect, since most chemicals are ineffective. After a few years, the insects disappear due to natural factors, and the damaged trees are completely restored. Of course, if you resist the pest, this process will be significantly accelerated. Insects will stop attacking the plant after two to three years.
Moth outbreaks
In the European part of Russia, the ermine moth infects trees in the Moscow and Leningrad regions. Outbreaks of activity of this pest were noted in the early 80s and mid-90s. In the late 90s, trees were damaged by it Krasnoyarsk Territory. In the early 2000s, this moth appeared in Khanty-Mansiysk. In 2006, a mass reproduction of the insect was observed in Sweden. In 2012, the epidemic began in Irkutsk. Every year the number of individuals increases, and this can lead to the fact that entire gardens and parts of forests will be infected. Despite the active fight against the pest, the following summer the moth returns again and with new strength destroys trees. The pest disappears only after a few years (from 2 to 5). At the same time, the fight should become more and more pronounced every year, since animals could develop immunity to previous means and preparations. 
Appearance of an insect
Ermine moth, the photo of which can be seen below, has a dim, but quite beautiful appearance. In Russia, white butterflies with three to five rows of small black specks on the front wings live. The hind wings are painted gray, as are the lower parts of the front wings. Their span is 20-26 mm. Butterflies are nocturnal.
The caterpillars of this insect are grayish-yellow in color, have black legs and a black head. Like the wings of butterflies, there are small specks on their sides.
Life cycle
The ermine moth lives for one year. At the end of summer, butterflies lay eggs on the trunk of a food tree, covering them with a shield of protective mucus. The caterpillars hatch 3-4 weeks after laying and remain under the shield throughout the winter. There they feed on the egg shells and partly on the bark. In the spring, they move inside the leaves and eat them from the inside, leaving the outer shell intact. As the caterpillars grow, they move to the outside of the leaf, creating a web of webs above them.
At the end of May, the grown caterpillars create nests from cobwebs on the tops of trees, which gradually expand. At the beginning of summer, insects pupate. Cocoons are located in groups in the forks of branches. By the end of June, new butterflies are born.
Damage caused
An overgrown colony of caterpillars can completely destroy a tree. But even if it doesn’t come to this, the apple tree or bird cherry tree on which the ermine moth has settled will suffer serious damage. Throughout their short life, the caterpillars destroy the leaves of the tree. First, they eat away the core (parenchyma) of the tender young leaves, leaving only the outer shell. Without internal cells, leaves cannot function, photosynthesis stops, leaves dry out, turn brown and fall off. Then, under the web, insects continue to eat the crown of the tree, leaving the plant without green cover. A plant that has lost its foliage cannot develop further; it slows down its growth and is unable to bloom or bear fruit. Subsequently, recovery may take more than one year.
In cities, the reason for pest control is not so much the likelihood of tree death, but rather the aesthetically unsightly appearance of plants that have been affected by ermine moths. Photos of such apple trees and bird cherry trees demonstrate how depressing and inappropriate they look on city streets.
Methods of pest control
No matter how terrible the ermine moth is, there are methods to combat it. If you treat the affected tree in a timely manner, it will not die and will continue to bloom and bear fruit after the recovery period. Treatment can be carried out with chemical insecticides, biological products based on a certain type of bacteria. You can also create pheromone traps that attract female moths. If the tree is not severely affected, you can manually collect nests and browned leaves. After collection, they should be burned along with the caterpillars. 
Features of chemical processing
The fight against ermine moths can be carried out with the following insecticides: Parisian greens, arsenic solution or Bordeaux mixture. If there are no more than two nests on the tree, you can use the drugs “Lepidocid”, “Danadim”, “Bitoxibacillin”. For private gardening, it is recommended to use the drug "Actellik", observing safety precautions, as it is very toxic. Tree treatment is carried out strictly before or after flowering! The first treatment is carried out in early May. The cocoons can then be collected from flowering trees by hand. In July, it is better to treat the tree again, since it is at this time that the grown individuals begin to lay eggs. 
Folk remedies
Not only professional biologists develop means of combating insect pests. Ordinary amateur gardeners can also tell you how to deal with ermine moths. For example, some summer residents recommend spraying trees with the following composition: add a bag of red pepper, a pack of shag, one bottle of potassium permanganate to a bucket of water, and add onion and garlic peels. The resulting mixture must be left for three days. If you don’t want to prepare the composition, you can spray regular Coca-Cola on the trees.
Another folk way consists not of etching, but of catching pests. To do this, the tree trunk is wrapped with tape with the sticky side facing out. The tape needs to be changed as it becomes filled with insects. Not only ermine moths will fall into such a trap. The control methods indicated above are also suitable for other insects. Pest attack on plants is a natural process, the same as prolonged rains or long heat. Save from any negative impacts plants will be helped by timely organized actions. It must be remembered that pests should be dealt with constantly until they completely disappear. If this is not done, the infected tree may die. And then the moth will move to other, still healthy plants, subsequently leading to their death.
May, everything around is blooming and fragrant, the garden is pleasing to the eye... And suddenly you notice a cobweb on the bird cherry bushes... No, these are not those silky threads that stretch harmless spiders. White dense cocoons are what will alarm you. Things can go so far that the entire bush will be shrouded in a cobweb. What happens to the bird cherry? What kind of trouble can you expect from this web?
Special signs
Ermine moths– small, mainly crepuscular and nocturnal butterflies. The wings are narrow, varied in color, in some species white with black dots, reminiscent of an ermine mantle. Caterpillars up to 18 mm long, often yellowish or greenish, live in colonies in web nests, which often envelop entire trees and bushes.
To the family ermine moths ( Yponomeutidae) besides bird cherry moth ( Yponomeuta evonymella) relate: apple moth ( Yponomeuta malinellus), fruit moth ( Yponomeuta padella), willow web moth ( Yponomeuta rorella), euonymus ermine moth ( Yponomeuta cognatellus), cherry shoot moth ( Argiresthia pruniella), cabbage moth ( Plutella xylostella) and other types.
Butterflies of bird cherry, apple, euonymus, willow and fruit spider moths are clearly distinguished from the others by the silvery-white color of the fore wings covered with black dots. The wing pattern is characteristic of the species and may, for example, consist of 12–16 black dots arranged in three irregular rows (apple moth), or 45–58 black dots arranged in five irregular rows (bird cherry ermine moth).
The caterpillars are yellowish in color and have longitudinal rows of dark dots on their backs. They live in spider nests where they pupate. Before pupation, each caterpillar spins a separate white cocoon.
From spider's nests
Caterpillars of the first instar of the bird cherry ermine moth overwinter under the scutes. They emerge from under them in the first half of May and immediately weave web nests. There are 15–45 caterpillars in one nest. They pupate in the second half of June in white dense cocoons arranged in compact packs.
Ermine moth caterpillars
The flight of butterflies occurs in July–August. During the day they sit motionless, often on the underside of leaves and in shaded places on branches; active flight begins before dusk and continues until dark.
Ermine moth butterflies
Two weeks after emerging from the pupae, the butterflies mate (usually in the evening) and after 5–6 days the females begin to lay eggs (finished in the second half of July) in groups (10–25 pieces each) on bird cherry branches, covering the oviposition with a shield. The hatched caterpillars remain for the winter.
When it's warm and damp
Mass reproduction of bird cherry ermine moths is facilitated by certain meteorological conditions - warm winter, mild spring, humid summer. This is exactly the situation that developed in 2005. Residents of Moscow and the Moscow region were concerned about damage to trees by insects eating foliage and entangling entire trees and bushes in thick webs. This trouble was caused by the massive reproduction of bird cherry ermine moth. Damage to trees by these butterflies has repeatedly occurred before, but to a lesser extent.
Bird cherry damaged by ermine moth
At the same time, fruit moths were observed eating the leaves of apple trees. This type of insect, just like the bird cherry ermine moth, entangles the foliage and shoots of trees it eats with a web and, after stopping feeding, pupates in woven nests in white spindle-shaped cocoons.
For Moscow and the Moscow region, even mass reproduction of the bird cherry ermine moth is not too dangerous phenomenon. These insects cannot cause much damage to the plantings; the trees will restore their foliage within the year of damage. But bushes shrouded in cobwebs, eaten leaves and shoots are not a pleasant sight.
Web nest of bird cherry moth
How to fight
Chemical treatment of damaged trees and shrubs is not very effective, since the caterpillars are well protected by a dense web. We can recommend collecting and destroying spider nests with caterpillars, without waiting for noticeable eating of the foliage.
________________________________________________________________
Willow ermine moth – Yponomeuta rorrellus (family Yponomeutidae, negative. Lepidoptera ). White with black spots on the wings, this butterfly looks like a lady dressed in ermine. Don't let the cute creature's innocent appearance fool you. Before us is a malicious pest.
Willow ermine moth
The fruits of her labors can be shocking: a gray dense web enveloping branches, sometimes entire trees, and sometimes even bushes growing nearby.
The willow ermine moth is common in forests and parks of the European part of Russia (except for the northern regions), North Caucasus, in Ukraine and in Western Europe. Caterpillars damage different types of willows ( Salix).
Butterflies
The wingspan of the butterfly is 18–26 mm. The forewings are white with a faint grayish coating and small black dots arranged in three irregular rows. The apex of the wing is dark gray. The hind wings are plain, dark gray.
The flight of butterflies is very extended - from the end of June to August. Single specimens can be found even at the end of September. The lifespan of butterflies is 40–60 days.
Females lay eggs on the smooth bark of young branches, usually near the buds, and cover the clutch with mucus, which hardens into a scute. The scutellum is elongated-oval, 5–8 mm long, initially yellowish-green, later dark gray, colored to match the color of the bark.
Caterpillars
Caterpillars of the first instar overwinter under the scutes. At the end of April, young leaves come to the surface and are mined. Several caterpillars feed in one mine. Upon emerging from the mine, the caterpillars weave web nests, wrapping them around several leaves on a branch. Each web nest contains from 25 to 75 caterpillars.
The color of the caterpillars changes with age from grayish-green to dark gray. The head is black, the occipital and anal scutes are black-brown. The integument is smooth, with very sparse whitish hairs.
During mass reproduction of the pest, branches, trunks and nearby bushes and herbaceous plants(sometimes even stumps and stones) are entwined with cobwebs.
Spider nests are untidy, with pieces of half-eaten leaves and caterpillar excrement. Having covered the leaves in one place, the caterpillars crawl to other branches, again entwining the leaves with cobwebs on them.
The caterpillars feed for 40–45 days. Afterwards, they concentrate on the trunks of eaten trees and pupate, arranged in vertical rows under a common thick layer of cobwebs. There are no cocoons. The pupae are 9–11 mm long, initially yellowish-green, later light brown. The development of the pupa lasts 12–15 days.
Struggle
Foci of mass reproduction are local in nature and quickly fade away. Caterpillars die from numerous entomophages, as well as entomopathogenic fungi.
Pest control is difficult because the caterpillars are well protected by webs. But it can be carried out during the transition of the caterpillars to open feeding (after leaving the mines). At this time, the plants are treated, if necessary, with suitable
In the photo Apple moth fruit leaf roller 
Pictured: Apple moth caterpillars
Apple moth or apple moth Simaethis pariana Cl. (syn. Anthophila pariana Cl.,),- a small butterfly with a wingspan of 10-12 mm.
The caterpillars are yellowish-green, have a light brown head and shiny spots on each body segment. Body length 12-13 mm. They live alone, skeletonize leaves on the upper side, and in case of danger they immediately leave the leaf, going down the web. Two generations of the pest develop per year. The most harmful is the second generation, which develops in late summer - early autumn and whose caterpillars cause massive damage to the leaves before drying out. Premature falling of leaves negatively affects the ripening of shoots and their frost resistance. Having finished feeding, the caterpillars of the second generation pupate, soon butterflies emerge, which, with the onset of frost, hide and overwinter until next year. The pest is widespread and damages all fruit and many berry bushes.
See what the apple moth looks like in the photo illustrating the different stages of development of the pest:
Control measures. Spraying in the spring, before the buds fully open and immediately after the end of flowering of apple trees, with the drug fufanon or its analogues (kemifos, karbofos). If there are a large number of second-generation caterpillars, repeat spraying with the same preparations is carried out at the end of summer or early autumn, taking into account the waiting period for each specific preparation. Collecting and burning fallen leaves.
In the photo, the pocket-edged moth 
In the photo of the caterpillar Moth moth
Pocket edge moth, or silver apple moth Ornix guttea Haw., is a very small butterfly with a wingspan of 12-13 mm. The forewings are narrow, dark brown with white silvery spots and a long delicate fringe of silvery color. The caterpillar is up to 5 mm long, with 7 pairs of legs, green, lives in pockets made from the curved edges of the leaf and skeletonizes the leaf from the underside. Two generations develop per year - summer and autumn. Significant damage is caused by caterpillars of the second generation, which are more numerous.
Control measures.Spraying trees immediately after flowering with one of the following preparations: fufanon, kemifos, kinmiks, actellik, spark, Inta-Vir. If the pest population is large, spraying is repeated in the summer with the same preparations, taking into account the waiting period.
In the photo, apple-leaf moth 
In the photo, the caterpillar of the apple moth
Apple leaf moth Lithocolletis pyrifoliella Grsm.- a very small butterfly with a wingspan of 8-9 mm. The wings are narrow, long, with a delicate fringe of silver color. The caterpillar is small, yellow-green, lives inside the leaf, feeds on the parenchyma and forms a characteristic mine. The mine on the upper side of the leaf is in the form of a wide oval spot up to 2.5 cm long, yellowish-brown, bubble-shaped, located along the veins. Excrement is usually located in the form of a lump in the central part of the mine. 1-3 generations of the pest develop per year.
Control measures.
Pictured is the apple ermine moth. 
The photo shows the caterpillars of the ermine moth
Apple ermine mothYponomeuta malinellus Zell. - a small butterfly with black dots on the front wings, the hind wings are silver-gray. The caterpillars are 17-18 mm long, yellow-white to dark gray in color, with two rows of black dots on the back. Caterpillars live in colonies, forming cobweb nests. Younger caterpillars overwinter in oviposition under the scutes. In the spring they bite into the buds, and then into young leaves, where they feed for 10-15 days. During the flowering of the apple tree, the caterpillars crawl out of the leaf blade and create a web tent of several leaves, which they feed on. Each brood can contain up to 70 caterpillars, which during their feeding period (35-40 days) constantly crawl to neighboring branches and form new nests. Having finished feeding, the caterpillars pupate inside the common nest in separate white cocoons. In June, white butterflies emerge, and after fertilization, the females lay eggs in clusters in the form of scutes. One female can lay from 20 to 100 eggs. The hatched caterpillars feed under the scutes, gnawing on the bark, and enter diapause until the spring of next year. The apple ermine moth is widespread and greatly harms apple orchards.
Control measures. Preventive spraying of trees during bud break and immediately after flowering with one of the following preparations: Fufanon, Kemifos, Kinmiks, Actellik, Iskra, Inta-Vir. Individual nests with caterpillars are cut off and destroyed. In case of large numbers, spraying is repeated with the same preparations.
How to deal with fruit ermine moth on an apple tree
In the photo, the ermine fruit moth 
The photo shows a fruit moth caterpillar
Ermine fruit moth Yponomeuta padellus L. (syn. Y. variabilis Z.)- a small snow-white moth with black dots on the front wings and a gray fringe on the upper edge. The hind wings are silver-gray. The eggs are oval, gray in color, located in oviposition in the form of scutes measuring 4-7 mm. The caterpillar is 17-18 mm long, from dark gray to yellow-white in color, has two rows of black scutes on its back, and from early spring it damages buds and young leaves, skeletonizing and eating them at the edges, causing the leaves to dry out half. During the flowering of the apple tree, the caterpillars weave cobweb nests and live in colonies of 20-70 pieces.
Having finished feeding, after 35-40 days the caterpillars pupate, each in a separate white cobweb cocoon, and these cocoons are scattered throughout the branch. The cocoons are thin, transparent, and a striped pupa can be seen inside. The head, chest and end of the abdomen are black, and the main part of the abdomen is bright yellow with a number of dark triangular spots. In June, butterflies emerge, feed on nectar, and females lay eggs in clusters in the form of scutes on branches. The fertility of females is 20-70 eggs. The hatched caterpillars gnaw the bark under the shield and enter diapause until the spring of next year. Damages all stone and pome crops, rowan, bird cherry, willow, ash and oak.
How to deal with ermine fruit moth on an apple tree is described in the previous paragraph.
How to fight pocket leaf miner on apple trees
In the photo, pocket miner moth 
The photo shows a pocket moth caterpillar
Mining pocket moth, or white-spotted pocket moth Ornix petiolella Frey (syn. Parornix petiolella FreyJ, is a small gray butterfly with a wingspan of up to 12 mm. The front wings are very narrow, gray, with numerous oblique light strokes, the hind wings are light gray, with a long delicate fringe. The caterpillars are very small, yellow-green, with 7 pairs of legs, live in white rounded mines under the upper skin of the leaf, eating away the parenchyma. The length is min 10 mm, and the width is 5 mm. Damages apple leaves and, less commonly, pear and stone fruit leaves.
How to fight moths on apple trees is described further on the page - use all available means and methods.
Control measures
In the photo, the hawthorn circle moth 
The photo shows the caterpillars of the hawthorn moth
Hawthorn circle moth Cemiostoma scitella L. - a small butterfly with narrow wings and long delicate fringe. They become entangled in the leaf parenchyma, forming mines. Mines in the form of small round wide spots of a dark color, usually several on a leaf, excrement arranged in a spiral visible through the skin. In addition to apple trees, moths are often found on hawthorn, cherry, and rowan.
Control measures. The same as against the pocket moth.
In the photo the apple moth 
The photo shows moth caterpillars
Apple moth Lithocolletis pomiella Grsm. - a small butterfly with a wingspan of 8-9 mm. The wings are long, narrow, fringed with delicate fringe. The black caterpillar lives under the epidermis of the upper side of the leaf and feeds on the parenchyma, forming a mine. The mine is spot-shaped, excrement is usually collected in the corner part of the mine.
Control measures. The same as against the pocket moth.
In the photo, the baby apple moth 
In the photo there is a baby moth caterpillar
Little apple moth, or little apple leaf miner Stigmella mallelli Stt., is a very small butterfly with a wingspan of up to 5 mm. The wings are thin, narrow, lanceolate, with a fringe of long shiny hairs. The head is covered with dense hairs, the first antennal segment is expanded, the venation of the wings is reduced. The caterpillar is yellowish-white, flat, legless, and feeds on the parenchyma inside the leaf, making long, thin, flagellate-like, often thread-like mines on the upper side of the leaves. It is widespread and causes the greatest harm to apple trees.
Control measures. The same as against the pocket moth.
In the photo, white apple moth 
Pictured is a baby moth caterpillar
White apple moth or apple miner moth Lyonetia clerckella L., is a small butterfly with narrow fore wings of silver-gray or brownish color.
There is a black protrusion at the apex, and 3 black spots on the leading edge. Hind wings with fringe. The caterpillars are light green, with a dark head and dark legs, body length 5 mm. The second generation butterflies overwinter and partly the eggs they lay at the base of the buds. In the spring, caterpillars emerging from eggs bite into young leaves and feed there. Overwintered butterflies lay eggs on leaves. The emerging caterpillars live inside the leaf blade and make narrow winding passages, filling them with their excrement.
Feeding lasts 20-25 days, the caterpillars gnaw a hole on the underside of the leaf and pupate near it in a white cocoon. After about two weeks, the butterflies emerge and begin laying eggs on the leaves. In September-October, butterflies of the second generation appear and overwinter. The baby moth severely damages apple trees, stone fruits, mountain ash, hawthorn, shadberry, and many deciduous trees in orchards.
Control measures. The same as against the pocket moth.
August 18, 2015
With the onset of May, a wonderful time begins in Russia, when cities dress up with bright greenery, the air is filled with the delicate aroma of flowering apple trees and bird cherry trees, and in their summer cottages gardeners prepare their pets for the autumn harvest. But it happens that trees are favored by various pests and people have to fight with them for the safety of green spaces. One such invader is the ermine moth. The insect has a number of characteristic features, each of which must be taken into account in the process of fighting it.
general description
The term “ermine moth” is the name given by biologists to the family of lepidopteran moths. It includes about 600 species of different insects. Their sizes are small: the wingspan is from six to twenty-eight millimeters. Such organisms live mainly in the tropics, but some species are also found in Russia.
Representatives of this family feed mainly on plants. Sometimes they can eat roots, more often leaves. Caterpillars settle on the stems and leaves of trees, gradually entangling them with cobwebs. In this way, social nests are created, where insects pupate one at a time or by gluing several cocoons together. Several hundred caterpillars can live on one tree. Plants often cannot cope with so many residents and die. Feeding on a certain type of plant, the moth harms forestry and agriculture.
Common types
About ten species of ermine moth can be found in Russia and neighboring countries. The greatest damage to forests and gardens is caused by insects that “specialize” on apple trees and bird cherry trees.
Apple ermine moth is found in the British Isles, Sweden and Finland, Siberia, as well as in Korea, Japan, in some areas of Canada and the USA. The caterpillars of this moth, dark yellow in color with black legs and spots, are also called "May worm" in some areas.
The bird cherry ermine moth lives over a vast territory from the Caucasus to China. As in the case of the apple tree pest, it is very difficult to combat this insect, since most chemicals are ineffective. After a few years, the insects disappear due to natural factors, and the damaged trees are completely restored. Of course, if you resist the pest, this process will be significantly accelerated. Insects will stop attacking the plant after two to three years.
Moth outbreaks
In the European part of Russia, the ermine moth infects trees in the Moscow and Leningrad regions. Outbreaks of activity of this pest were noted in the early 80s and mid-90s. In the late 90s, trees in the Krasnoyarsk Territory suffered from it. In the early 2000s, this moth appeared in Khanty-Mansiysk. In 2006, a mass reproduction of the insect was observed in Sweden. In 2012, the epidemic began in Irkutsk. Every year the number of individuals increases, and this can lead to the fact that entire gardens and parts of forests will be infected. Despite the active fight against the pest, the next summer the moth returns again and destroys trees with renewed vigor. The pest disappears only after a few years (from 2 to 5). At the same time, the fight should become more and more pronounced every year, since animals could develop immunity to previous means and preparations. 
Appearance of an insect
The ermine moth, a photo of which can be seen below, has a dim, but quite beautiful appearance. In Russia, white butterflies with three to five rows of small black specks on the front wings live. The hind wings are painted gray, as are the lower parts of the front wings. Their span is 20-26 mm. Butterflies are nocturnal.
The caterpillars of this insect are grayish-yellow in color, have black legs and a black head. Like the wings of butterflies, there are small specks on their sides.
Life cycle
The ermine moth lives for one year. At the end of summer, butterflies lay eggs on the trunk of a food tree, covering them with a shield of protective mucus. The caterpillars hatch 3-4 weeks after laying and remain under the shield throughout the winter. There they feed on the egg shells and partly on the bark. In the spring, they move inside the leaves and eat them from the inside, leaving the outer shell intact. As the caterpillars grow, they move to the outside of the leaf, creating a web of webs above them.
At the end of May, the grown caterpillars create nests from cobwebs on the tops of trees, which gradually expand. At the beginning of summer, insects pupate. Cocoons are located in groups in the forks of branches. By the end of June, new butterflies are born.
Damage caused
An overgrown colony of caterpillars can completely destroy a tree. But even if it doesn’t come to this, the apple tree or bird cherry tree on which the ermine moth has settled will suffer serious damage. Throughout their short life, the caterpillars destroy the leaves of the tree. First, they eat away the core (parenchyma) of the tender young leaves, leaving only the outer shell. Without internal cells, leaves cannot function, photosynthesis stops, leaves dry out, turn brown and fall off. Then, under the web, insects continue to eat the crown of the tree, leaving the plant without green cover. A plant that has lost its foliage cannot develop further; it slows down its growth and is unable to bloom or bear fruit. Subsequently, recovery may take more than one year.
In cities, the reason for pest control is not so much the likelihood of tree death, but rather the aesthetically unsightly appearance of plants that have been affected by ermine moths. Photos of such apple trees and bird cherry trees demonstrate how depressing and inappropriate they look on city streets.
Methods of pest control
No matter how terrible the ermine moth is, there are methods to combat it. If you treat the affected tree in a timely manner, it will not die and will continue to bloom and bear fruit after the recovery period. Treatment can be carried out with chemical insecticides, biological products based on a certain type of bacteria. You can also create pheromone traps that attract female moths. If the tree is not severely affected, you can manually collect nests and browned leaves. After collection, they should be burned along with the caterpillars. 
Features of chemical processing
The fight against ermine moths can be carried out with the following insecticides: Parisian greens, arsenic solution or Bordeaux mixture. If there are no more than two nests on the tree, you can use the drugs “Lepidocid”, “Danadim”, “Bitoxibacillin”. For private gardening, it is recommended to use the drug "Actellik", observing safety precautions, as it is very toxic. Tree treatment is carried out strictly before or after flowering! The first treatment is carried out in early May. The cocoons can then be collected from flowering trees by hand. In July, it is better to treat the tree again, since it is at this time that the grown individuals begin to lay eggs. 
Folk remedies
Not only professional biologists develop means of combating insect pests. Ordinary amateur gardeners can also tell you how to deal with ermine moths. For example, some summer residents recommend spraying trees with the following composition: add a bag of red pepper, a pack of shag, one bottle of potassium permanganate to a bucket of water, and add onion and garlic peels. The resulting mixture must be left for three days. If you don’t want to prepare the composition, you can spray regular Coca-Cola on the trees.
Another popular method is not to poison, but to catch pests. To do this, the tree trunk is wrapped with tape with the sticky side facing out. The tape needs to be changed as it becomes filled with insects. Not only ermine moths will fall into such a trap. The control methods indicated above are also suitable for other insects. Pest attack on plants is a natural process, the same as prolonged rains or long heat. Timely organized actions will help save the plant from any negative influences. It must be remembered that pests should be dealt with constantly until they completely disappear. If this is not done, the infected tree may die. And then the moth will move to other, still healthy plants, subsequently leading to their death.
