Silkworm Nun

Butterfly with chalky white wings and numerous dark transverse wavy stripes and spots. The hindwings are greyish-white with small dark spots along the edges. This butterfly is characterized by high color variability from the described basic form to completely dark-colored (sometimes even black) individuals.

The female in the wingspan reaches 45-55 mm, has a short sawtooth antennae and a pointed reddish posterior end of the abdomen with black spots.

The shape of a sitting butterfly resembles an isosceles triangle. The male is smaller and reaches 35-45 mm in wingspan; the antennae are pinnate, the abdomen is evenly finished grayish-black, the outline of the sitting male resembles an equilateral triangle.

Caterpillars of the first age are mostly black, covered with rather long hairs 3-4 mm long. An adult caterpillar has a length of 30-35 mm.

The main color is from light green to dark; there are six blue warts on each segment, which are covered with gray hairs. The first thoracic segment is attached to the head in a straight line. A dark dorsal stripe begins on the second segment, which is interrupted by a characteristic light spot from half of the seventh to half of the ninth segment. The dark stripe ends at the eleventh segment. The pupa is brown, shiny with light brushes of hairs, which are bluish-steel on the dorsal side. Pupa length 18-20 mm. Based on the shape of the base of the antennae and signs of future genital organs on the underside of the abdominal segments, one can distinguish the sex of future butterflies.

The eggs are initially orange-brown, later brown with an opal sheen.

The nun silkworm is distributed throughout Europe, and partly in Asia south of the 60th parallel, so it is found from Portugal to Japan. It has also been recorded in the Himalayas. The southern border of its distribution in Europe stretches from the Iberian Peninsula towards the Balkans. In Russia, the nun silkworm is found in the forest zone and in the forest-steppe of the European part (in the south - very rarely), it was recorded in the Crimea and the Caucasus (including Transcaucasia), in the Urals and in the Volga region, in the forest-steppe of western Siberia, in Altai , in the Baikal region and on Far East(Priamure, southern Primorye, southern Sakhalin). Outbreak areas mass reproduction in Russia, in addition to the zone of coniferous forests of the European part, are Altai, southern Primorye and Sakhalin.

In the south, the nun silkworm rises higher and, in addition to conifers, is often found on deciduous trees. In the north, it also lives on the plains, mainly on spruce and pine.

Butterflies of the silkworm-nun appear in nature depending on the weather, different geographical location and altitude from the second half of July to August. Like all moths, they appear after dark, mostly between 21:00 and 24:00 or before dawn. Fertilized females lay eggs in clusters of 20-50 between or under tree bark scales, and the eggs are very well hidden. In general, one female lays about 200 eggs. The eggs overwinter and the caterpillars emerge in the spring of the following year. The yield is very dependent on temperature: middle Europe usually begins at the end of April, in mountainous areas and more northern areas - in May.

The caterpillars stay together, forming a so-called "mirror". Only a few days later, they begin to eat the young, blossoming needles of spruce shoots, as well as old pine needles. In places, biting out the blossoming leaves hardwood. Starting from the second age, the caterpillars are very voracious, they begin to bite even older spruce needles. If they develop on hardwoods, only a part near the median vein is left at the leaf blade. In the same period, new pine shoots are already eaten on the pine.

Caterpillars go through 5-6 instars during their development. The first lasts an average of 18 days, from the second to the fourth - each one week, and the last is again longer - about 2 weeks. The duration of individual periods is highly dependent on temperature, and at the same time on the weather. The entire development lasts at least 52 days, but on average takes about 9 weeks. Adult caterpillars stop feeding, leave shoots and look for suitable places for pupation, most often between scales of tree bark or in whorls of branches. The pupae are attached to the trees with just a few threads. The pupal period lasts 8-14 days. The first butterflies to come out are the males; females also appear. Adults do not feed and live only 10-14 days. Silkworm Nun - dangerous pest spruce and pine plantations. It also occurs on deciduous species, especially if these species are an admixture in infected coniferous plantations or are located in their immediate vicinity (for example, beech, hornbeam, birch, maple, English oak, small-leaved linden, hazel, as well as aspen, alder, etc. .). In the centers of mass reproduction and with a lack of food, the caterpillars descend to the grassy cover and eat, for example, blueberry leaves, etc.

Outbreaks of mass reproduction of the nun silkworm occur in Central Europe in homogeneous and even-aged spruce and pine-spruce plantations at the age of 40-60 years, most often, however, in areas outside indigenous spruce forests 400-600 m above sea level. y. m. In especially favorable and warm years outbreaks of mass reproduction were also observed in spruce forests above 1000 m a.s.l. y. m. Pandemics of the nun silkworm are known in Central Europe.

The adult insect has a rusty brown or dark brown flat body with elongated head, antennae slightly longer than the head. The edges of the shield are rounded and widened. The body is strongly flat, widened behind, with a noticeable edge of the abdomen. The female reaches a size of 4.5-5 mm, has an ocher rusty-brown color, its number in the population is 60-70%. Females have two morphologically different forms: 1. macropteric - winged females, which under optimal development conditions are quite small (only about 2%) and represent a morphological and ecological type of adaptability, since when living conditions deteriorate, their number in the population increases sharply; 2. females are wingless - brachypterous, which have only rudimentary hindwings - elytra, so they cannot fly.

Control measures should be planned for the start of an outbreak when more than 30% defoliation in fir and spruce, cedar pine, or severe (70%) larch defoliation is predicted. As a rule, aerial treatment of forests with insecticides is carried out. The most promising biological drug to date is lepidocide.

Nun silkworm (Lymantria monacha L.)

Damaged species: Pine and spruce; can also damage fir, larch, cedar. Of deciduous trees and shrubs, it damages aspen, birch, willow, mountain ash and others.

Nature of damage: Caterpillars, having left their eggs, feed on young needles of May shoots, which have not yet emerged from their covers. Adult caterpillars eat old needles, biting needles at different heights from the base.

Distribution: Throughout Europe, Western and Eastern Siberia, Baikal, Amur, Primorye, in the south of the Kuriles and Sakhalin, in Japan and China (at least in the East). In Western Siberia and the Krasnoyarsk Territory, the foci are confined to ripe and overmature forest-steppe forests, where they operate almost simultaneously with the pine moth foci.

Morphology: Butterflies of very variable coloration, with four black sinuous transverse stripes and black speckles on the forewings, may be whitish with a clear black pattern, completely smoky with no pattern at all, and pure black. Hindwings are gray with small black spots along the edges (Fig. 2). Female with black filiform antennae, with black and pink stripes on the abdomen; wingspan 40-55 mm. Male with feathery brown antennae, wingspan 25-35 mm. The eggs are almost spherical, the size of a poppy seed, somewhat flattened at the poles. Newly laid eggs are light pink, then darken. Young caterpillars are dark gray with a black shiny head, with six pairs of yellowish warts on each body segment, on which long, thin hairs are located. Adult caterpillars up to 50 mm, gray with a yellow-brown head, hairy warts are bluish-gray. A double dark stripe runs along the back, which diverges in the middle of the body, covering a light spot. The pupa is brown with tufts of gray hairs, without a cocoon, attached by sparse cobweb threads between the needles or on the branches and trunk.

Life cycle: Butterflies fly from mid-July to mid-August, in the evenings and at night. During the day, they sit motionless on tree trunks. Females lay their eggs in clusters of 25 to 145 deep in crevices and cracks in the bark. In Siberian pine forests, ovipositions are located in the butt of trees up to a height of 50 cm from the ground. On average, one female lays 200-300 eggs. Wintering occurs at the egg stage. In early to mid-May, young caterpillars emerge from the eggs, which remain together for some time, in a cluster called the "mirror", and only after a few days rise to the crown. Caterpillars go through five instars and in the first ten days of July they begin to pupate in the crown of the tree and on the undergrowth. Towards the end of July, butterflies emerge from the pupae. Taking into account that damage to the crowns by the nun silkworm occurs in the first half of summer, the death of plantings in the foci of the pest is extremely rare. Usually undergrowth dries up in the foci, trees upper tier successfully recover even after intense damage.

Silkworm monk (Ocneria monacha L.) - a butterfly from the family. Liparidae, belonging to the group of silkworms Bombyces. About 2 1/3 cm. length and span up to 6 cm. lat. White with black spots: one on the head, two on the back and several spots on the wings, on which, in addition, there are wavy-toothed transverse narrow stripes, sometimes merging at the middle of the wing into one wider strip. Abdomen of female with black and pink bands, ends with retractable ovipositor; antennae black, serrated. The male antennae are feathery, brown, the abdomen ends with a fluffy tassel.

Eggs are slightly smaller than poppy seeds, smooth, without fluff, freshly laid pinkish, later brownish-gray. Caterpillar up to 6 cm. length, 16-legged, hairy; the head is dark brown, with black dots; hairs sit in tufts on tubercles located in two rows along the back and the same number on the sides; gray, with a yellowish or greenish tint; on the back of the 2nd ring there is a velvety black, heart-shaped spot, from which a dark strip extends to the rear, bifurcating into 7-9 rings around the light spot; there are two white spots on the chest rings on the sides; in the middle of the 9th and 10th rings, one red wart each.

Pupa up to 2 1/2 cm. length, shiny, with a bronze tint, with tufts of yellowish-white hairs arranged in bands. Butterflies fly in July and August in the evenings. Eggs are laid in heaps of 20-50 pieces each, and only one female - about 250 eggs; they are usually hidden in cracks and under the scales of the bark, under moss and lichens on the trunks and on the main roots protruding from the ground. The eggs hibernate. Hatching of caterpillars begins in April and continues until mid-May. Caterpillars, after leaving the egg, sit quietly on the bark with whole broods and then crawl to the tops of trees to feed.

Young caterpillars are densely covered with especially long hairs and are able to secrete a lot of cobwebs; they often have to fall from the branches, especially when they do not find suitable food, and this will certainly happen in those forests that in previous years were gorged on caterpillars; fallen starving caterpillars hang on cobwebs, are picked up by the wind and carried by it to distant places, just as seeds are carried with a hairy fly. With a mass appearance, caterpillars falling and carried by the wind envelop entire trees with numerous cobweb threads, like a cloth, and connect them to each other with cobweb bridges, along which they then freely crawl.

Half-adults stop spinning webs. Caterpillars of M. are almost omnivorous, but in their youth they need needles of freshly blossoming buds. On old needles, at first they give out only greens from the surface and jagged the needles along the edges; growing up, they eat whole needles, especially short spruce needles, and the caterpillar begins to eat a pine needle from the middle and eats its entire lower half, while the upper one falls off uneaten; under pine trees during an attack on them by caterpillars of M., one can constantly find freshly eaten crumbling needles and fallen caterpillars, which usually does not happen under spruce trees; pine suffers much less from spruce from M. Suffer from caterpillars and others conifers, with the exception of juniper and yew.

Of hardwoods, they do not touch alder, pear, ash, lilac, privet, euonymus and currants with gooseberries; beech, apple, birch and oak are especially eager to eat. On trees with long-leaved leaves, such as birch, aspen, etc., the caterpillar very often eats up the petiole of the leaf on which it was attached and strengthened, and falls with it to the ground; but also on others deciduous trees she throws a lot of leaves half-eaten, sometimes clustering under the trees in whole heaps.

Caterpillars do not touch vegetables and herbs. Caterpillars mostly feed during the night (especially adults), and hide during the day. At the end of June, pupation begins. The pupae are placed among several cobwebs, on the bark or on the branches, and after two weeks butterflies begin to emerge from them. M. belongs to the devastatingly harmful forest insects.

It is found in almost all coniferous forests south of the Ezel-Kazan-Perm line, but ordinary conditions is sometimes a rather rare insect for decades; in other years, it begins to multiply intensively and bare forests in areas defined by thousands of square meters. miles. In the period 1846-67. in the forests of West Prussia and adjacent Russia, M. devastated coniferous forests over 7000 sq. geographical miles, of which 600 miles belonged to Prussia, and the rest was the share of Russia (relative to Russia, this figure is greatly exaggerated).

Recently ended the latest, last period of devastating reproduction of M. (1888-95) in South Prussia and in some places in Austria and Russia; in our country, and also in Austria, during this period, M. brought comparatively insignificant harm, but Bavaria and Württemberg calculated their losses in millions of marks. M. brings the greatest harm to spruce forests, multiplying in them initially by nests in dense, dark ripening plantations; the mass stay of caterpillars in the same spruce forest lasts 2-3 years, after which, due to a lack of food, the caterpillars begin to die in masses from a rotten disease. In a pine forest, M. occurs more often (and in Wed. Russia - mainly), but it harms less.

Control measures:

1) applying adhesive rings to trunks in early spring;

2) collection and destruction of eggs and crushing of broods of young caterpillars;

3) collection and crushing of female butterflies;

4) attraction of butterflies to fires and

5) protection and attraction of insectivorous birds.

Kulagin, "Insect harmful to forests M." (M., 1894). Iv. Shevyrev.

Butterfly with honey-white wings and numerous dark transverse wavy stripes and spots. The hindwings are greyish-white with small dark spots along the edges. This butterfly is characterized by high color variability from the described basic form to completely dark-colored (sometimes even black) individuals. The female in the wingspan reaches 45-55 mm, has a short sawtooth antennae and a pointed reddish posterior end of the abdomen with black spots. The male is smaller and reaches 35-45 mm in wingspan; antennae pinnate, abdomen evenly finished greyish-black. The shape of the sitting butterflies resembles an isosceles triangle. The pupa is brown, shiny with light brushes of hairs, which are bluish-steel on the dorsal side. Pupa length 18-20 mm. Based on the shape of the base of the antennae and signs of future genital organs on the underside of the abdominal segments, one can distinguish the sex of future butterflies. The pupae are attached to the trees with just a few threads. The pupal period lasts 8-14 days. The first butterflies to come out are the males; females also appear. Adults do not feed and live only 10-14 days. The eggs are orange-brown at first, later brown with an opal sheen. Caterpillars of the first age are mostly black, covered with rather long hairs 3-4 mm long. An adult caterpillar has a length of 30-35 mm. The main color is from light green to dark; there are six blue warts on each segment, which are covered with gray hairs. The first thoracic segment is attached to the head in a straight line. A dark dorsal stripe begins on the second segment, which is interrupted by a characteristic light spot from half of the seventh to half of the ninth segment. The dark stripe ends at the eleventh segment. Caterpillars go through 5-6 instars during their development. The first lasts an average of 18 days, from the second to the fourth - each one week, and the last is again longer - about 2 weeks. The duration of individual periods is highly dependent on temperature, and at the same time on the weather. The entire development lasts at least 52 days, but on average takes about 9 weeks. Adult caterpillars stop feeding, leave shoots and look for suitable places for pupation, most often between scales of tree bark or in whorls of branches.