Treatment of chestnuts from mining moths. Chestnut miner moth control measures. Pupa of the chestnut miner
On the leaves of trees, shrubs and herbaceous plants, spots resembling patterns are often visible. They are called mines and are caused by pests - miner insects that gnaw through passages and under the skin of leaves.
Miners damage both conifers and deciduous trees, almost all shrubs, agricultural crops, both ornamental and medicinal plants, flowers and weeds.
Among trees, for example, horse chestnut, linden, holly, plane tree, robinia, mountain ash, thuja, apple tree; among the bushes privet, rose, skumpia, hawthorn, honeysuckle, spirea; among herbaceous plants - goldenrod, balsam, strawberry, clover, clematis, stonecrop, euphorbia, bluebell, centaury, dandelion, violet.
Usually miners of one species damage a certain type of plant, which is reflected in their names - poplar moth, linden moth, nightshade miner.
Most miners overwinter in the pupal stage, some in the larval or adult stage (adult). In the imago stage, miners hibernate in bark cracks and other shelters, for example, in buildings. In the larval stage, miners hibernate on the soil surface, in caps on branches, in mines in fallen leaves, and in the pupal stage, in the soil, fallen leaves, and cracks in the bark.
Some species of miners always have only one generation, while the number of generations of other species depends on the temperature during their development.
Some types of miners damage leaves only in spring, others in summer, and still others from spring to autumn. The periods of development of individual generations overlap, which complicates the determination of the timing of protective measures.
Among the leaf miners, representatives of Lepidoptera (miner moths) and Diptera (agromysid flies), lesser beetles (gold beetles, leaf beetles, weevils) and Hymenoptera (true sawflies) predominate.
Mina - " business card» miners. Each type of miner is characterized by a certain form of mines, their location in a sheet, and in mines - larvae, excrement and flight holes. The mines may be shaped like a tunnel, a spot, or a tunnel with a spot at the end.
The harmfulness of miners is manifested in a decrease in the viability of plants, their decorative effect, growth rates, fruiting intensity and deterioration in seed quality. The harmfulness of miners increases in areas where one or more closely related plant species are cultivated, in greenhouses, nurseries, on plantations of medicinal or forest monocultures.
As a result of the development of mines, the leaf surface decreases, which retains dust and atmospheric emissions, carries out photosynthesis, which affects the growth of trees. Additional flowering of heavily miner-damaged plants in autumn also weakens them. The branches of such trees sometimes freeze. With a high density of mines, the decorative effect of plants and resistance to diseases and pests are reduced, the foliage falls off prematurely. A decrease in the mass of seeds of a plant damaged by miners can affect the safety of seedlings and the quality of planting material. Damage to, for example, linden by a miner leads to a decrease in the number of emerging flowers and their nectar content, which damages beekeeping.
Especially dangerous are miners, which quickly spread over a vast territory with wind currents, vehicles, and most of all with planting material. The number of these species in their homeland is regulated by natural enemies - birds, invertebrates, and fodder plants grow together with other plant species, which increases the stability of plantings. If a plant that serves as food for miners in a new territory is grown as a monoculture (in landscaping, on plantations), the harmfulness of these insects increases many times over.
Leaf miners on trees and shrubs
Examples of miners that have penetrated us from other continents are chestnut, or ohrid, leaf miner (Cameraria ohridella), white locust moth (Parectopa robiniella), white locust miner (Phyllonorycter-Macrosaccus robiniella), sycamore moth (Ph. platani), juniper moth (Dichomeris marginella), thuja moth-garden (Argyresthia thuiella) ).
chestnut miner
Damages the leaves horse chestnut, which grows in natural forests in the Balkans, and in other countries is used for landscaping parks, squares and streets. This miner was first discovered near Lake Ohrid in Macedonia on the border with Albania in the 1980s. and received the name "Ohrid miner". This species quickly spread throughout Europe, and in last years occurs in almost all areas Three generations of the chestnut miner develop during the season, and the mass flight of the first generation of butterflies occurs during the flowering of the chestnut. Pupae of the latest generation overwinter in mines in fallen leaves.
acacia miners
White acacia, or Robinia, as an ornamental breed in early XVII V. brought to Europe, at the end of the XVIII century - to Ukraine. This breed is widely used, in particular, in hedges. Acacia miner moths entered Europe from North America about 30 years ago, they have 2-3 generations per year. Mines of two types are easily distinguished externally.
Linden moth moth (linden miner).
Described in Japan in 1963. For two decades, it has spread to Primorye, Korea, penetrated the European part of Russia, Ukraine and many European countries. Butterflies of the linden miner hibernate in cracks in the bark of linden trees, lay their eggs on the lower surface of the leaves after they have fully bloomed. Butterflies of the summer generation fly out in early July, and butterflies that will hibernate appear in September.
Thuja moth.
It entered Europe from North America in the early 1970s. 20th century Inhabits thuja western and Lavson's cypress. Has one generation a year.
The larvae mine the apical shoots and overwinter in the mines. The needles turn brown, and the populated shoots die.
Juniper moth.
Damages the needles of common juniper. Caterpillars hibernate in dense cobweb tubes. In spring, caterpillars continue to feed, pupating in early May. New generation caterpillars appear in June and feed until autumn. They mine needles, weave juniper branches with cobwebs, which leads to yellowing of needles and loss of decorative plants.
Among ornamental shrubs miners damage: roses, rhododendron. holly holly. On the leaves of rose bushes, you can see light dots (the result of piercing a pink mining moth when laying eggs) and winding passages. Rhododendron leaves are damaged by the azalea moth (Caloptilia azaleella). Its caterpillars are quite large - up to 1 cm in length. Damaged leaves dry up, crumble and fall off. Adult caterpillars crawl onto neighboring healthy leaves, fold them into tubes and continue development there. They pupate on the underside of leaves in cocoons. On the holly, leaf miners are also detected by the presence of punctures and passages.
Leaf miners on herbaceous plants
Among the miners that damage herbaceous plants, flies from the family Agromyzidae – polyphagous miner (Liriomyza strigata), polyphagous miner (Phytomyza horticola), chrysanthemum leaf miner (Phytomyza syngenesiae), nightshade miner (Liriomyza bryoniae).
Agromizidae flies damage agricultural crops (wheat, sugar beet, onion, cabbage, corn) and flower plants(chrysanthemums, violets, freesias, gerberas, carnations, zinnias). The polyphagous miner has several generations per year in the leaves of cyclamen, cineraria and other flower crops.
nightshade miner damages tomato, cucumber, gourds, parsley, celery, cabbage, lettuce and dozens of other plants. Not only larvae, but also adult flies harm herbaceous plants, piercing leaf tissue and feeding on cell sap. As a result, the leaves of young plants wither and fall off. With a large number of flies, the plant may die.
Plant protection against leaf miners
Protecting plants from leaf miners includes several techniques.
Selection of resistant plant species and varieties. Miners do not inhabit all types of plants of the same genus. Thus, on the meat-red chestnut, the larvae of the chestnut miner die at a younger age, and the small-flowered chestnut is not colonized by this pest at all.
Plant inspection. The sooner damage to plants by miners is detected, the less damage they will cause. Be aware that miniature flies can spread with potted or cut flowers.
Sifting the soil before using it for greenhouses and potted plants spend, because the pupae of many miners hibernate in it.
Fine mesh insulation indoor plants when exposed to a balcony or garden, it allows you to protect them from wind-blown mining flies.
Hanging records (boards, pieces of plastic) yellow color, smeared with glue, in greenhouses and in open ground along the rows of plants at the level of the location of the main mass of foliage, in order to catch flies and moths during their summer.
Applying adhesive belts to the trunks just before the start of the summer of miners.
Manual removal of infested leaves or their parts, followed by destruction.
Cleaning up fallen leaves is the easiest and safest for environment an event to protect trees from miners wintering in fallen leaves. The leaves must be raked without damaging them so that the pupae do not spill out, and then not burned, but composted.
Digging trunk circles and loosening the soil under the crowns.
Washing of miner moths with a jet of water from a tree trunk during the mass summer of each generation.
Application in chemicals. Insecticides to protect ornamental plants from miners are used by spraying foliage, soil under plants, as well as injection into the trunk. However, injection into the trunk is expensive, creates conditions for the penetration of pathogenic microorganisms into the tree, and the introduction of insecticides into the soil is dangerous for many of its inhabitants. In the presence of several generations of miners, several foliage sprays are carried out per season.
Chestnuts as a remedy for moths have long been known among the people. You just need to know how to use them correctly for the proper result.
Any person is familiar with such a tree as chestnut. But in fact, few people thought about the areas in which its fruits are used. In fact, the fruit gifts of this tree have proven themselves as a means to effectively deal with moths at home. At the same time, the effectiveness of this method has been fully proven: once a study was conducted during which a chestnut was placed in the pocket of a fur robe, and after a few days all the moth simply died.
If the hostess has a need to fight moths at home, then in this situation it is not necessary to use various chemically active substances. Here, both raw and dried chestnuts can help her. At the same time, the effectiveness of both 1 and 2 options will be noticeable.
But if you decide to use raw fruits, then you can place them only in a room that will be very well ventilated in the future.
In unventilated places, raw chestnuts quickly become moldy, which is why their effectiveness is reduced several times. Therefore, it is advisable to first dry them in any way, and only then use chestnuts as a means that can fight various types of insects.
In order to quickly get rid of pests, you should first prepare a cabinet, and only then lay out the fruits in this place:
If the hostess wants the efficiency of chestnuts to be higher, very often they are recommended to simply chop them before putting them in the closet. To do this, do the following:
- It is necessary to break the fruits into very small pieces with a hammer.
- The resulting pieces must be placed in some kind of fabric bag or simply wrapped in ordinary fabric.
- Bags with pieces of this product can be safely laid out in the wardrobe between items of clothing and things.
If the owner adheres to these rules, then he will be able to quickly get rid of insects at home.
In what cases is the method with chestnuts against moths effective?
Very often, many doubt that the "chestnut method" is an effective tool in the process of fighting moths. In fact, this method has its own unique feature, since only these fruits can scare away the butterfly itself, because of which they will simply not be able to lay new eggs in things. Naturally, chestnuts will not be able to get rid of the larvae themselves. But if the hostess noticed a butterfly flying nearby, then they will not allow their smell to lay eggs in clothes. In the event that a person wants to 100% get rid of the butterfly itself, then he needs to perform the following actions:
If people have moths in their clothes, then you can get rid of it through the use of chestnuts. But if adult butterflies have already laid larvae, then in this situation such a method will not be effective. Since he does not kill the larvae, and sooner or later new adult butterflies will hatch from them.
A diverse and numerous family of moths is able to penetrate and mischief everywhere: in residential buildings, on grocery and industrial warehouses, in fields with cultivated crops, orchards and, of course, in the beds of vegetable gardens and summer cottages.
The moth is especially fond of feasting on the leaves of house plantings, which carries a mortal threat to many green spaces (tomatoes, pears, apple trees, etc.).
Appearance and biological cycle
Evil harmful insect with its habits it resembles the behavior of a caterpillar (for which it received the corresponding name). It also gnaws long "corridors" of tunnels in the foliage. Also affects only the inner side of the leaves, leaving the outer layer intact. A plant attacked by a moth quickly weakens, withers and inevitably dies.
The pest, having climbed deep inside the leaf, is hidden under the shell of the so-called egg, under the protection of which it will be until the time comes to turn into a butterfly.
We are used to thinking of moths as an unattractive, small, grayish insect. However, the mining moth stands out from the general mass of relatives, having an unexpectedly bright appearance. The color of her body and wings can be orange or brick brownish (depending on the subspecies). But not of a uniform shade, but richly decorated with stripes white color or spots.
An adult butterfly of an insect of small size, with a span of both wings no more than 1 cm. A mature individual is endowed with a long proboscis, with which it sucks the life-giving juice from the unfortunate green victim. The egg clutch of one female is up to 50 eggs, and they can be scattered over different leaves of the plant. The larvae emerging from the eggs are wrapped in a dense cocoon, from which they do not get out to the surface until a certain time, but at the same time actively devouring sheets and gnawing tunnels in it.
When the time comes for the larva to turn into a caterpillar, its legs grow, with the help of which the pest moves very quickly from leaf to leaf. At small insect surprisingly powerful mouth jaws, even the toughest foliage is subject to them. 
The caterpillar still avoids appearing on the surface. For the time being, for the time being, it is inside its pre-laid passages, simultaneously expanding them. After 10-11 days of continuous devouring of the plant, the caterpillar turns into a chrysalis, and then a butterfly emerges from it. A new biological cycle begins.
The greatest danger of damage to plantings by a mining moth is that it settles on a plant in whole colonies. Considering that thousands of new pests will appear from the laid eggs, it is not surprising that the insect leaves behind entire plantations of ruined plants. And having run a lot in one area, turning into butterflies, the colony flies to another.
The main part of the species of mining moth prefers certain plants:
tomato;
potato;
honeysuckle;
chestnut.
However, there are also "omnivorous" species that do not disdain absolutely any green spaces, including vegetables, flowers, shrubs.Not only do insects harm with their actions, they are also carriers of viral diseases: mosaic, fusarium wilt, etc.
Varieties of miners with photos
Attacks melon plantings, fruit bushes, tobacco, celery leaves, soy.
Loves garden flowers: chrysanthemums, zinnias, violets. The initial appearance of the pest can be detected on the sheets by a large number of punctures on their surface. Then there are tunnels. If you look at the affected sheet in the light, then the moves will be seen very clearly. The larva gives preference to the most tender part of the leaf, juicy and soft. This is the area around its edge.
South American tomato
The tomato moth is native to southern America.It causes irreparable harm to cultivated nightshade plantations: eggplant, tomato, potato, etc.
More recently, South American miners have migrated to European countries. They spread on seedlings, penetrate into greenhouses and vegetable gardens. This moth infects the whole plant, not just the leaves. As a result, the culture droops, its leaves fall, the ovary dries, and in the end, the plant rots in the bud. When the signs of damage are already clearly expressed, it is very difficult to deal with pests, almost useless. The losses are too great. An area that has been attacked by a tomato miner is declared a quarantine zone. This extends to everything from plant seeds to crops.
chestnut
This kind of mining moth appeared on European territory earlier than the tomato moth. The southern cities of Europe everywhere use horse chestnut as urban decorations, and this is a favorite delicacy of the pest of the same name.
The insect does not just capture vast territories. It overwinters beautifully at any stage of the biological cycle. Preservation of chestnuts has long been the concern of the state. Considerable amounts are allocated from city budgets for combat and prevention. Every spring, chestnut alleys are treated with special chemicals. Or they use a very effective, albeit quite expensive method: they put insecticide injections directly into the trunk.
Cherry and apple
Fruit mining moths prefer to settle on fruit trees private or industrial gardens.
The pest can overwinter in the bark of the trunk, and in the spring get to the surface and begin its disastrous business.The female produces egg laying on very young, only blossoming leaves. Such trees will lag behind in development, bloom late and form ovaries. Pests are very difficult to detect on initial stage. To do this, gardeners go to the trick: they tie small yellow planks to the branches of trees to attract the insect.
Beetroot
The fight against mining moth
It is not easy to defeat a harmful insect; in the larval and caterpillar stages, it is not very susceptible to poisons and chemicals. But you can fight with adult flying individuals. So they will not acquire offspring and do not form new colonies.
Carefully inspect and cut off all leaves with the slightest traces of punctures on the surface (oviposition).
Collected affected leaves are subject to destruction by fire, in no case can they be used for compost and other purposes.
It is necessary to carry out preventive examinations systematically throughout the season, especially paying attention to the plants adjacent to the patient. Preventing the spread of miners is easier than exterminating them later.
At the stage of appearance of butterflies from moth pupae, plants cover with non-woven fabrics. This is an effective tool for vegetable and melon crops and small shrubs.
It is good to spill the leaves of trees with water from a hose. The procedure is carried out before the start of flowering every day.
Treat greenhouses with insecticidal preparations before seedlings are planted, also carefully examined. For adult plants and seedlings, quarantine is required before planting in a permanent place for at least 10 days.
As chemical agent used for pest control drugs with feverfew. Every 2-3 days the plant is sprayed, a total of 5-6 times. With low efficiency, the processing is repeated. The same tool can shed the soil (dilute in water). To prevent the appearance of moths, it is periodically necessary to spray the plants with an infusion of chamomile.
The defeat of plants by mining moths is, of course, a very unpleasant situation, but do not rush to put an end to your plantations. With due diligence and taking comprehensive measures, it is possible to defeat a harmful insect. For greater efficiency, it is desirable to unite with neighbors in order to destroy the existing colonies by mass events and prevent their spread to neighboring areas.
Video "We fight tomato moths. The best drugs for pests"
Infection is detected already when the plant weakens, begins to hurt and often dies. Several years may pass from the moment of settlement to the moment of death, during which the colony of miners continuously expands and increases.
The adult is predominantly nocturnal, but the caterpillars are active almost around the clock.
Leaf mining moth: where to look and how to find?
Miners, at their core, are almost omnivorous. They can settle on the leaves of almost any plant. However, they also have their favorite treats. Most often found on:
- cherry, sweet cherry, pear and apple tree;
- chestnut;
- spray roses and rhododendrons, juniper;
- violets, chrysanthemums, petunias and zinnias;
- home flowers in flowerpots;
- tomatoes, cucumbers, radishes, potatoes, eggplant, zucchini, lettuce.
One of the varieties of leaf miners is, which is activated during flowering and fills the apartments of residents, under whose windows poplars are planted.
This pest migrates quite actively, so there is a high probability that, if measures are not taken in time, one can not only lose the crop, but also completely lose perennial plantations.
And in order to start the fight in a timely manner, it is important to understand what leaves infected with miners look like. Almost always, punctures can be seen on them, which are made by a leaf mining moth with a thin proboscis. From them come winding passages of light beige, reddish, rusty or Brown. More severe lesions are indicated by pitted edges and large holes in the leaves.
In addition, often reverse side leaf, you can see the cocoon, which is the "home" of the miner caterpillar. When the leaves fall, the cocoon enters the soil, and the pest in it is able to calmly survive the winter and enter the active phase immediately after the snow melts.
Mining moth on cherries and other plants: methods of control on the example of one crop
Suppose cherry trees miners liked in your garden. If the lesions are still minor, you can try to cope with them without the involvement of specialists, using gentle methods. For example:
- collect and burn damaged leaves, including those on neighboring trees;
- hang yellow adhesive boards: this color attracts insects, and landing on a layer of adhesive substance, the insect will not be able to take off again and will die. Planks need to be changed as the surface is filled;
- populate insect predators that feed on pests, such as riders;
- a mining moth on a cherry will feel uncomfortable if the tree is regularly treated with rapeseed or mustard oil;
- you can knock down pests from a tree by dousing with a jet of water under strong pressure;
- young trees are sometimes covered with a non-woven material that protects the seedling from attacks by mining pests. In the same way, by the way, garden beds can be protected from moth invasions.
If such methods do not bring results, you will have to turn to insecticides for help. Pyrethrum-based preparations are considered the most effective. However, it is quite toxic, so a number of rules should be observed when working with the composition:
- protect open areas body mask and gloves;
- carry out spraying in the morning and evening during the period of minimum activity of insects that destroy miners;
- carry out the procedure at least five times with breaks of 3-5 days.
Given that moth larvae are quite tenacious, they can continue their development, even when they get into the soil. Therefore, with a strong infection of the site, a deep strait of the beds with a preparation containing pyrethrum is recommended.
The main measures to combat mining moths on chestnuts are similar to those described above. But there are also differences. Considering that chestnuts, as a rule, are planted for decorative purposes in crowded places, namely, in park areas, in alleys and in public gardens, it is better to replace spraying with insecticides with intra-stem injections - this method of treatment will cause less harm to the environment.
It should also be borne in mind that miners quickly adapt to new conditions, therefore, during prolonged use of the same insecticidal preparation, its effectiveness may decrease. In this case, it is worth changing the remedy to one that is close in action, but based on a different component.
Chestnut mining moth, or Ohrid miner (lat. Cameraria ohridella) is an invasive species of butterfly from the moth family, which is the main pest of horse chestnut, destroying the foliage of trees.
Less common on other types of horse chestnut, as well as maples and girlish grapes. The range of the species covers most of Europe and continues to expand every year. It is found everywhere where forage plants grow: in parks, on roadsides and in urban green spaces.
Chestnut miner moth - dangerous pest horse chestnut, causing serious damage to urban plantings of this tree. The damage caused by this species in Europe amounts to hundreds of millions of euros per year.
The history of the distribution of the chestnut leaf miner in Europe
The history of the distribution of the chestnut miner moth from 1984 to 2007.
Adult specimens of the Ohrid miner were noted in the early 1980s in the vicinity of Lake Ohrid in Macedonia, and in 1986 were described by Gerfried Deschka and Nenad Dimic as the new kind. Some time after the description, a gradual spread of the species to the north was recorded.
Over the course of just a few years, the chestnut mining moth populated the territory of Croatia, Hungary and Romania. After the discovery of the Ohrid miner near the city of Linz in Austria in 1989, it was noted that this species moth began to rapidly occupy new territories and by 1994 reached the Czech Republic and Germany.
In Poland, it was first noted in 1998 in Lower Silesia, and in five years it has already settled throughout its territory. In some areas, the finds of this moth appear to be an accidental introduction associated with road and rail transport, since they are far beyond the boundaries of the expanding area of the range. The range expansion rate in Poland was 100 km per year.
In 2002 the chestnut leafminer was recorded in Sweden, Denmark and the UK. In 2003, it was first noted in Russia in the Kaliningrad region. In 2006, the species was noted in the south of Finland in the city of Hanko, where it was apparently brought on ferries from Germany. In 2007, the moth was recorded for the first time in Lithuania, then in Latvia (Liepaja) and Estonia (Tartu).
As of 2011, the chestnut leafminer has been recorded in the following countries: Austria, Albania, Belgium, Bulgaria, Bosnia, Great Britain, Hungary, Germany, Herzegovina, Greece, Denmark, Spain, Italy, Kosovo, Latvia, Lithuania, Liechtenstein, Luxembourg, Macedonia, Moldova, the Netherlands, Poland, Romania, Serbia, Slovakia, Slovenia, Turkey, Ukraine, France, Czech Republic, Switzerland, Sweden, Croatia and Estonia, as well as in the European part of Russia. But the range of the chestnut leaf miner still continues to increase, due to the widespread use throughout Europe and Asia of the horse chestnut tree for ornamental purposes in urban and suburban areas. In Russia, the moth is found in the Kaliningrad region (since 2003), in the Bryansk, Kursk, Belgorod, Rostov, Orel, Smolensk regions and in Moscow.
During the summer and autumn of 2013, the species began to spread throughout Norway, in particular, it was noted in Fredrikstad, Frogne and Oslo.
Imago chestnut miner moth
Imago is an adult insect, up to one centimeter in wingspan, can reach 7 mm in length. The wings are reddish-brown in color, interspersed with white lines. The chest is brown, the abdomen is gray, the legs are black and white.
Eggs of the chestnut miner
The eggs are very small - 0.3 mm in length, light green.
Caterpillars of the chestnut miner
Caterpillar of the first age, 0.8 mm long, light green, translucent. The body is flattened, strongly narrowed towards the posterior end. The first thoracic segment is wide (approximately 0.2 mm), noticeably wider than the rest of the thoracic segments. Head capsule 0.1-0.15 mm long and 0.11-0.2 mm wide, golden brown, almost transparent.
Caterpillar of the second age, 2 mm long, light green, translucent, with light hairs. Head capsule 0.24 mm long and 0.25 mm wide, golden brown, almost transparent. The first thoracic segment is wide - an average of 0.3 mm.
Caterpillars of the third age are about 3.5 mm long, yellowish green or pale yellow. Body with sparse light hairs; dorsal setae on 2nd-3rd thoracic and 1st-8th abdominal segments brown. The first thoracic segment is also wider than the others, up to 0.75 mm wide. Head capsule 0.35 mm long and 0.40 mm wide, light brown, shiny.
Caterpillars of the fourth stage are 4.5 mm long, usually light green or yellowish green. Body more or less cylindrical, markedly narrowed posteriorly after fifth abdominal segment. The first segment of the chest is 0.78 mm wide. The head capsule is the same color as the body, 0.35-0.4 mm long and 0.45-0.5 mm wide.
Caterpillars of the fifth age are 4.5-6 mm long, greenish-gray. The body is covered with hairs; dorsal setae of thorax and abdomen black. The first segment of the chest is 1.1 mm, the widest is now the third segment, which is 1.26 mm wide. The head capsule is brown.
Caterpillars of the sixth age are 4.2-5.5 mm long. The body is dull, pale green or whitish-yellow, with light hairs, fusiform. The first thoracic segment is narrower than the second and third segments and a number of subsequent abdominal segments. The head capsule is 0.5 mm long and 0.45 mm wide, almost the same color as the body: from pale green to pale brown.
Pupa of the chestnut miner
Pupa 3.25-5.7 mm long, dark brown, with short light hairs. The apex of the head is characteristically beak-shaped. On each, from the second to the third, abdominal section there is a pair of curved hooks with which the pupa, protruding from the mine, clings to the cocoon or epidermis - the outer integumentary layer of the leaf, before the butterfly emerges. It is noteworthy that sexual dimorphism at this stage is quite clearly expressed - male pupae are morphologically different from female pupae: in them, unlike female pupae, the seventh segment is distally expanded.
Development of the chestnut miner moth
Females lay from 20 to 82 eggs in a lifetime, placing them randomly, on the front side of the leaf; often deposited near its lateral vein, sometimes near the central vein, but rarely near the vein of the third order. On one leaf blade of a complex chestnut leaf, different females can lay from 20 to 84 eggs. Embryonic development lasts from 4 to 21 days, depending on the ambient temperature.
One of the main features of the development of the chestnut miner moth and other species of the family is hypermetamorphosis - a method of development in which caterpillars of different ages differ sharply; the caterpillar goes through six phases of development, while the caterpillars of the first - third ages differ from the caterpillars of the fourth and fifth ages in their way of life and nutrition, which, in turn, is reflected in their external difference. In the sixth phase of development, caterpillars spin silk and do not feed.
The caterpillars of the first three phases of development feed only on plant sap (hence this stage is called the "sap-eating phase") and form mines in the epidermal layer of the leaf or directly under the skin. Caterpillars of the fourth and fifth phases switch from feeding on cell sap to feeding on the tissues themselves of the upper part of the leaf mesophyll (the so-called “tissue-eating phase”), while forming more spacious and deeper mines in the leaf.
The body of these caterpillars becomes more or less cylindrical, they acquire well-developed pectoral and ventral legs. Their head becomes semi-prognathic, the mouthparts are well developed. Caterpillars in the sixth phase of development do not feed ("non-feeding phase"), but spin silk to build a cocoon. Caterpillars at this stage of development are distinguished by a reduction in the mouth apparatus, a well-developed spinning apparatus, and a more fusiform body shape. For 20-45 days, depending on the climate and season. According to A. M. Gerasimov (1952), two instars were distinguished in the genus Camereria within the sixth phase: in the first, caterpillars make the lining of the cocoon, in the second, its inner part; moreover, caterpillars ready to pupate are able to populate the cocoons of previous generations.
Having emerged from the eggs, caterpillars of the first age penetrate under the cuticle into the epidermal layer of the leaf of the fodder plant. There they begin to absorb the juice, usually making a straight, slightly curved course along the vein. This passage in the epidermal part is silvery, 0.7-1.5 mm long and 0.3-0.5 mm wide. Caterpillar excrement in this section of the mine shows a black central line(width 0.05 mm at the beginning and 0.08 at the end), which is formed by sections interconnected by spots. Then the caterpillar in the epidermal layer of the leaf forms a spotted mine with a diameter of 1 mm, where it starts to molt. In this place, the line of excrement forms a spot-like part of an irregular spherical shape. Sometimes the spotted part of the mine is pale brown. Caterpillars that form such mines can already begin to feed on the juice of the cells of the upper layer of the plastid parenchyma.
Caterpillars of the second age completely switch to feeding on the cell sap of the host plant leaf. By the end of the second instar, the larvae form a rounded mine 2–3 mm in diameter. Caterpillars of the third age still feed on cell sap in top layer palisade parenchyma.
First, the caterpillars expand the mines in a circle, while the excrement completely covers the bottom of the mine, forming black concentric circles. Rounded mine with a diameter of 6-8 mm, dark. At the fourth age, the caterpillars switch from feeding on juice to feeding on tissues of all layers of the palisade parenchyma. The length of the mine is already 16 mm on average. At the fifth age, the caterpillars continue to feed on tissues. Mina is 18 to 31 mm long and 6-8 to 12-14 mm wide. Caterpillars of the sixth age do not feed at all. They first clear the site of exuviums and head capsules of previous ages to build a cocoon and get down to business.
Only pupae enter suspended animation. In cold regions, before wintering, caterpillars predominate over pupae in a quantitative ratio, and most of the caterpillars die. After frosts, only individuals that have practically completed feeding can survive; during thaws, they are able to pupate.
Adult insects in nature appear at the very beginning of the chestnut flowering, the appearance of petals. Butterflies hatch (appear) from pupae mainly in the first half of the day. In the second half of the day, there are isolated cases of hatching.
Life cycles
Mass flight of butterflies occurs in May, coincides with the flowering of horse chestnut.
Females lay eggs one by one on the upper surface of leaf blades, mainly near the veins. The eggs are very small, the female covers each of them with a transparent secret, which dries over the egg in the form thin film. Embryonic development lasts 7–10 days. Hatching greyish-green caterpillars gnaw out a cavity in the palisade fabric. Initially, the mines are small, in the form of brownish rounded spots with a darker spot in the center and a lighter border around the edge. As the caterpillars grow, the mines become elongated; with dense population, they can occupy almost the entire leaf blade. On one sheet sometimes there are several tens of mines.
After 10–12 days, in the second or third decade of July, the butterflies fly out.
In the conditions of Moscow and the Moscow region, the butterfly gives two full-fledged generations.
In 2008, the beginning of the development of the third generation was observed in this region.
According to experts from the Main botanical garden them. N.V. Tsitsina Russian Academy Sciences (GBS RAS), in 2016, in the third decade of August, the third flight of butterflies of the chestnut mining moth began. This is due to sufficient for the development of the third generation of butterflies for summer season sum of positive temperatures.
The wintering of the second generation chestnut miner moth takes place at the pupal stage in fallen leaves or butterflies, huddled in bark cracks in the butt of trees. Apparently, the wintering features of the moth ensured it wide use with planting material in numerous urban landscaping and private areas.
Ecology
The chestnut miner moth is one of two species (along with Cameraria aesculisella from North America) of this genus that feed on horse chestnuts. Caterpillars live and feed inside leaves. various kinds horse chestnut, less often maple. The caterpillars feed mainly on the sap of the leaves of white-flowered horse chestnuts, such as the common horse chestnut and the Japanese horse chestnut from the section Aesculus, which are the least resistant to caterpillars. On some horse chestnut trees, not all individuals survive, since these species have a smaller nutritional value. These species include yellow horse chestnut, naked horse chestnut, red horse chestnut and forest horse chestnut from the Pavia section. Some chestnuts are completely destructive for most moths, namely Aesculus glabra var. sargentii (from section Pavia), small-flowered horse chestnut, Assam horse chestnut, California horse chestnut, Chinese horse chestnut and Indian horse chestnut (from sections Macrothyrsus and Calothyrsus). It was noted that on Chinese horse chestnut and Aesculus glabra var. sargentii, caterpillars die when they reach an older age, and on small-flowered horse chestnut, Assam horse chestnut, California horse chestnut, Chinese horse chestnut and Indian horse chestnut, caterpillars of the first and second ages do not survive.
Of the chestnut hybrids, Aesculus bushii has the least resistance to damage by caterpillars, Aesculus dallimorei, Aesculus dupontii, Aesculus glaucescens, Aesculus plantierensis and Aesculus woelintzense are slightly more resistant, Aesculus arnoldiana and Aesculus hybrida are even more resistant. Horse chestnut meat-red and Aesculus neglecta are detrimental to younger ages caterpillars.
In Europe, it has been noted that caterpillars can also develop in the leaves of various maple species, in particular, Norway maple and white maple, but feeding on these plants leads to increased mortality of miner, as from, for example, meat-red horse chestnut. In 2006, in Kyiv, caterpillars were noted on girlish five-leafed grapes, which is considered to be native to North America.
Having penetrated the leaf, the caterpillars feed on its juice, which is why yellow or reddish traces, the so-called mines, begin to appear on the outer side of the leaf. The concentration of mines on horse chestnut can be very high - up to 700 minutes per leaf.
However, in Europe there is a fungus Guignardia aesculi, which also infects the leaves of horse chestnuts and leaves spots on them that are outwardly almost indistinguishable from mines of a chestnut miner moth. They differ from mines in a yellow border and the absence of a caterpillar inside the “mine”, as well as in the fact that the fungi form pycnidia - black bubbles on an already brown section of the leaf.
Caterpillars, making mines, can reach the borders with neighboring mines of caterpillars of the same species, as a result of which the mines can merge. If a large number of caterpillars live in a leaf, then the leaf, because of them, completely loses its green mass, becomes brown and fades, and already at the end of summer (July - August) such wilted leaves fall - much earlier than if the leaves fell healthy in autumn.
Harm caused by chestnut mining moth
The chestnut leafminer causes such serious damage to the plantings of the common horse chestnut in Europe that in some places (for example, in a number of regions of Germany) it calls into question the advisability of further cultivation of this tree in cities.
The damage caused by caterpillars is expressed, in particular, in the fact that damaged chestnut crowns do not provide trees with sufficient accumulation nutrients which leads to freezing in winter. If complete freezing does not occur, trees badly damaged by chestnut mining moths do not bloom well in spring, and individual branches dry out. On weakened trees, as a rule, other pests that damage leaves, shoots, trunks, and fungal infections develop.
