FORESTS A forest is a thread tied at one end to a rod and the other to a hook. For the most part, it is twisted from the hair of a ponytail; but there are scaffolds of silk, filament, and prepared from some Indian plant, with transparency quite similar to white

All living things can get sick, and trees are no exception. Their health can be compromised for a variety of reasons, not the least of which are a variety of pests. Sometimes they hit an already weakened tree, sometimes they choose a completely healthy one. Worst of all, pests easily infect one tree after another, and it is not always possible to detect an infection in time. How to check the status of each tree in a huge forest? Very often, the disease is detected when a significant area is already affected.

How does a mass infection proceed and how to determine it?

In order for mass infection to begin, most often a combination of several factors is necessary. First, without pests, there will be no infection. There must be some of them in the forest. It can be a variety of butterflies and beetles, as well as fly larvae, caterpillars and many other tiny animals. The second necessary condition is a favorable situation for the active uncontrolled reproduction of pests. Good weather, lack or complete absence of natural enemies, the presence of a large amount of food and some other factors will definitely provoke a massive infection of the forest with pests.

So, the existence of favorable conditions is in fact the first stage of infection. Then, once in a favorable environment, pests actively multiply. This is the second stage of mass infection. There are more and more of them. On average, this period can last up to three years.

When there are really a lot of pests, the second period begins, accompanied by a strong defeat of the forest. It is an outbreak of infection as such. This state of affairs rarely lasts longer than two years. In the end, the excessive number of pests leads to the fact that they do not have enough food, diseases spread among them, more and more predators appear, of which they are natural prey. This period also lasts about a year or two.

To determine whether there is a massive pest infestation in a forest area, special criteria are used, both qualitative and quantitative.

As for the quantitative criteria, they are as follows:

1. The degree of population, it is also the absolute population, which is the number of pests in an area equal to one tree or one square meter of soil.
2. The multiplication factor is determined by comparing the number of pests in different periods, for example, last year and the year before. To know it, you need to calculate what is the ratio of the more recent degree of population to the older one.
3. The flare slew rate is intended to show how quickly the hazard is growing. To determine it, a certain period before the outbreak is compared with the period after it. When calculating the growth rate of an outbreak, one should calculate the ratio of the degree of population in the period that falls on the outbreak, with the degree of population in the period before it.

Forest pests in faces

The pine scoop is a nondescript brown butterfly with white spots, but its caterpillars are elegant - dark green, with snow-white longitudinal stripes. Females lay eggs on the branches, from which caterpillars are born, diligently nibbling first young, and then everything, needles. This can kill the tree or weaken it. In the latter case, it may be attacked by other pests, for example, barbels. The natural enemies of pine scoops are birds that feed on caterpillars.

There are many types of longhorn beetles. Let's take black pine as an example. These are rather graceful black beetles with very long whiskers that devour the bark of branches and occasionally needles. For laying eggs, they prefer to choose trees that are weakened by something. The larvae, having been born, as a rule, are quite capable of finishing them off.

The blue goldfish, a beautiful bug of a dark blue color, with a tint of either black or green, also infects pine trees, preferring weakened ones, and lays its eggs in cracks in the bark. The four-spotted goldfish, a pleasant-looking brownish-golden bug, behaves in the same way.

How do you deal with forest pests?

Nowadays, there are several methods of pest control, and each of them is necessary in its own way.

To prevent mass infections, there is a forestry method. It consists in carrying out a series of preventive measures that are highly likely to prevent infection. If the seedlings are healthy, the ecological situation is stable, and the observation is constant, it will be more difficult for pests to flood the site.

The physical and mechanical method of struggle consists in the timely destruction of pests using, so to speak, brute force. A good example is collecting resin-affected pine cones before the larvae turn into beetles.

The biological method of struggle requires a competent approach, but difficulties often justify themselves. It allows you to force nature itself to fight pests. For example, the natural enemies of a particular pest are taken, and they are given the opportunity to properly hunt. Of course, ideally, these natural enemies should already live on the site, but the population may be insufficient or even absent. In the case of a sufficient number of such animals, they should be protected as much as possible so as not to face mass infection due to the lack of predators. You can also purposefully infect pests with various diseases, for example, marsupial fungus can kill most of the population of nun silkworm caterpillars.

The most dangerous and radical pest control method is chemical. It should be resorted to only in extreme cases, when the infection is so great that other methods no longer help. Affected areas are treated with pest-destroying substances. Unfortunately, they, as a rule, kill not only pests and have an extremely bad effect on the ecological situation.

List the types of pests and types of forest diseases that exist on the territory of the nearest forestry (forest park). Specify the family, genus, species (Latin name) of at least 10 species of insects, their food species; 5 types of diseases, and their pathogens and signs

insect pest plant predator

Types of pests that can be found on the territory of the Tula forestry:

a) Coniferous insects:

Common pine sawfly (lat. Diprion pini) (Fig. 1)

Rice. one.

Genus - Diprion;

View - Common pine sawfly;

Feeding base - Pest of Scotch pine throughout its range.

Young caterpillars feed together on shoots, eating needles from the sides, so that the median vein remains intact. Caterpillars have 5 instars and their feeding period lasts at least 4-5 weeks. Adult caterpillars, which, unlike young ones, are much lighter, eat the needles entirely, so that only stumps remain, and often eat the bark of the shoots. The older the caterpillars are, the more food they consume during the day. Therefore, with sufficient population density in the crown, complete defoliation occurs. False caterpillars feed from August to October, when most of them migrate into the soil, and a smaller part remains in the cracks in the lower part of the bark at the base of the trunk.

Red pine sawfly (lat. Neodiprion sertifer) (Fig. 2)

Rice. 2.

Family - pine sawflies;

Genus - Neodiprion;

View - Red pine sawfly;

Feeding base - Pest of Scotch pine throughout its range. The larvae feed on the leaves and juices of the tree, thereby damaging its branches.

b) Leaf-eating insects:

Goldtail, or golden silkworm, or golden worm (lat. Euproctis chrysorrhoea) (Fig. 3)

Rice. 3.

Family - a butterfly from the family of wavelets (Erebidae)

Genus - Euproctis

View - Goldentail

Food base - The most important biotopes are parks and orchards. Previously, the home of the Goldentail was light deciduous mixed forests.

Green oak leaf roller (lat. Tortrix viridana) (Fig. 4)

Rice. four. Green oak leaf roller (lat. Tortrix viridana)

Family - Leaf roller

Genus - Tortrix

View - Green oak leaf roller

Lump base - Caterpillars feed on the leaves of a number of broad-leaved trees, in particular oak, as well as maple, birch, hornbeam, beech and poplar. In addition to trees, some types of shrubs, including representatives of vaccinium and nettle, can become fodder plants.

c) Stem pests:

Bark typograph (lat. Ips typographus) (Fig. 5)

Rice. 5.

Family - Weevils

View - bark beetle typographer

Feeding base - It feeds on the bark of coniferous trees, gnawing passages in it.

Large spruce black barbel (lat. Monochamus sartor) (Fig. 6)

Rice. 6.

Family - Mustachioed

Subfamily - Lamiin

Genus - black barbel

View - Barbel black spruce big

Feed base - confined to coniferous forests. They mostly prefer mountainous areas. Occurs in clearings and windbreaks. Adult insects gnaw the needles, roots and bast of young coniferous branches. In general, the larvae prefer the common spruce (Picea abies), as well as the common pine (Pinus sylvestris), fir and other conifers.

Zlatki (lat. Buprestidae) (Fig. 7)

Rice. 7.

Family - Coleoptera

Genus - Zlatki

Feed base - Pests of deciduous species predominate among borers, the fauna of coniferous species is relatively poor in species. Each species prefers one or more tree species close to each other and inhabits a certain part of the tree trunk, branches or roots. Thus, most of the small anthaxias (of the genus Athaxia) inhabit the branches and top of the trunks, and the dicerci (genus Dicerca) settle in the lower part of the trees.

Many species of borers are very active and attack relatively healthy trees, populating them before barbels and bark beetles. For their reproduction, they choose sparse, well-heated plantations growing in xerophilic conditions, primarily edges, backstage, undercuts, groups of seed plants in cutting areas, shelterbelts and plantings without lateral shading, second tier and undergrowth.

d) Pests of nurseries, forest crops and young stands:

Western May beetle or Western May beetle (English Melolontha melolontha) (Fig. 8)

Rice. eight.

Family - Lamellar

Genus - Melolontha (May beetles)

View - May western Khrushchev

Food base - feed on the leaves of trees and shrubs - oak, beech, maple, elm, hazel, poplar, willow, walnut. Of the fruit crops, plums are most preferred, and of forest crops, oak is the most preferred.

Common bear (lat. Gryllotalpa gryllotalpa) (Fig. 9)

Rice. 9.

Family - bears

Genus - bears

View - Common Medvedka

Food base - feeds mainly on plant roots, earthworms and insects.

e) Entomophages of forest pests:

Ladybugs (lat. Coccinellidae) (Fig. 10)

Rice. ten.

Family - Ladybugs

Type - Arthropods

Class - Insects

Squad - Coleoptera

Food base - Ladybugs feed mainly on sedentary arthropods that form large colonies. Among the preferred groups are aphids, mealybugs, whiteflies, spider mites. There are known cases of feeding on larvae and pupae of leaf beetles, eggs and larvae of bugs, caterpillars of butterflies, etc. The more food ladybugs have, the more prolific the females are.

Red forest ant (lat. Formica rufa) (Fig. 11)

Rice. eleven.

Family - Ants

Genus - Formica

Species - Red forest ant

Food base - They feed mainly on plant sap, aphids and other sucking insects, during the feeding period of larvae - mainly insects.

Types of diseases of woody plants identified in the Tula region. Their pathogens and symptoms.

Types of plant diseases are a group of diseases that can be caused by different biotic and abiotic factors, but have similar sets of symptoms.

Schutte - comes from the German word schutten (to crumble, crumble). This type includes coniferous diseases caused by fungi and characterized by premature drying and falling off of the needles. Depending on the type of pathogen and the stage of development of the disease, the needles acquire a yellow, brown, red-brown, red, gray color. An important sign of infectious drying is the formation of sporulation of the pathogen in dead needles.

The causes of non-infectious desiccation can be unfavorable natural (damage by animals and insects, low or high temperatures) and anthropogenic (air and soil pollution, recreational process) factors.

Schutte lead to the weakening and death of young plants (Fig. 12).

Rice. 12.

Powdery mildew is characterized by the formation of superficial white, initially cobwebbed, later compacted powdery leaves on the affected organs. Leaves and young shoots look as if sprinkled with flour. The causative agents of this type of disease are powdery mildew fungi. Powdery mildew affects many deciduous trees and shrubs. Powdery mildew of oak (Microsphaera alphitoides), maple (Sawadaia tulasnei and S. Bicornis) is widespread. Powdery mildew leads to the weakening of young plants, significantly reduces the decorative effect of trees and shrubs. Affected young shoots do not have time to lignify and may suffer from early autumn frosts (Fig. 13).

Rice. 13.

Bark necrosis is the death of the outer tissues of trunks and branches, occurring in separate areas or around the circumference of the affected elements of the crown. In some cases, the affected bark differs in color from the healthy one, in others, its color does not change. Local necrosis is often delimited by callus ridges and fissures. Necrosis of the cortex is mainly caused by fungi, less often by bacteria. In the first case, characteristic fungal structures are formed in the dying and dead bark: conidiomas, fruiting bodies, stroma. An example of necrosis of fungal origin are: tubercular (Tubercularia vulgaris) and cytosporic (fungi of the genus Cytospora) - on hardwoods, cenangium (Cenangium ferruginosum) - on pine and other conifers.

Bacterial necrosis is characterized by the formation of swellings and cracks on the cortex, from which a transparent liquid darkens in air. Of the diseases of this type, bacterial necrosis of poplar (Pseudomonas syringae) and beech (Erwinia horticola) is most common.

Necrosis leads to the weakening and drying of trees and shrubs, contributes to the development of foci of stem pests (Fig. 14).

Rice. fourteen.

Crayfish. When diseases of this type are affected, neoplasms appear on trunks and branches, sometimes on roots: stepped and non-stepped wounds, ulcers with callus or resin nodules, smooth or fissured tumors (growths). Causes of cancer can be caused by fungi, bacteria and exposure to low temperatures.

In cancerous diseases of fungal origin, conidiomas, fruiting bodies, and stroma develop in the affected areas. Many widespread diseases are caused by fungi: stepped (ordinary) hardwood cancer (Nectria galligena and N. Ditissima), black poplar cancer (Hypoxylon mammatum), resin cancer (seryanka) of pine (Cronartium flaccidum and Peridermium pini) and others.

A sign of bacterial cancer is often a transparent, brown liquid that flows out of the cracks in the bark. In some cases, this feature is absent. The most common are: wet ulcerative vascular cancer of poplar (Pseudomonas syringae and P. cerasi), transverse oak cancer (P. quercina), tuberculate pine cancer (P. pini).

A sharp drop in temperature in winter leads to the formation of longitudinal cracks (frost cracks) on the trunks of deciduous and coniferous species, elongated along the length of the trunk up to 1 m or more. Over time, cracks can turn into typical wounds. Elm, oak, maple, linden, and spruce are more often exposed to frost.

Cancer diseases lead to the weakening and gradual drying of trees and shrubs, contribute to the infection of trunks with rot, the formation of windbreak and the colonization of trees by stem insects (Fig. 15).

Rice. fifteen.

Witch's brooms are tightly packed, numerous, thin, shortened vertical shoots that form from dormant buds on a small segment of a branch. They are spherical or oval in shape. The reason for the formation of witch's brooms on woody plants are often fungi and viruses, in more rare cases - insects and various abiotic factors. Witch's brooms of fungal origin are often found on birch (Taphrina betulae), fir (Melampsorella caryophyllacearum). Infectious witch's brooms can develop over several years or decades.

Rice. 16. Tree disease type - witch's broom

Man wins more and more territories from nature. In this struggle, he is opposed by an army of pests: insects, microorganisms, animals. Expecting a high harvest, we sometimes unexpectedly encounter a huge number of uninvited guests in the field, in the garden, in the garden. It's too late to fight pests while they destroy our plantings. It is best to take care of prevention.

Pest classification

Agricultural pests are divided into:

• Insects.
• Microorganisms.
• Worms and slugs.
• Animals.

Pests are divided on a territorial basis. They may be characteristic of your region or be present in gardens and orchards everywhere. Certain pests, most often microorganisms, are characteristic only for greenhouses. According to the type of damage, the enemies of agricultural crops are divided into:

1. Pests of the root system.
2. Eaters of leaves and stems.
3. Pests of ovaries and kidneys.
4. Fruit destroyers.

Microorganisms

Microorganisms are airborne or enter along with damage caused by other pests. There are obligate microorganisms that do not exist outside the plant, and conditionally phytopathogenic, capable of living in other environments. The first group is dangerous because, being unable to exist outside the carrier, it uses its potential to the full, significantly weakening crops. The second form can be transmitted over long distances and cover large areas. Just like insects, garden pests are highly specialized in one group of plants. Damage to plants is caused by:

Among plant pests, the class of worms includes nematodes, which mainly affect the roots. Slugs are content with leaves and shoots. There are many folk remedies for dealing with them. The slug is noticeable in the garden, and the harm from its activities is also noticeable. This gave rise to a lot of signs. Slugs belong to the class of gastropods. Most of all, they love the ripe fruits of strawberries. A snail is the same slug, only with a shell. It can eat leaves of cabbage, cucumber, horseradish and other plants. If the leaf is damaged, pathogenic microorganisms are introduced, the process of photosynthesis is disrupted. The plant is forced to compensate for their growth by fruiting.

Rodents cause great damage to agricultural crops. They damage both roots and fruits. There are cases of crop damage by large flocks of birds.

Insects

In order to understand which insects are considered pests, it is necessary to classify them. Many of them are involved in pollination of plants, destroy fungi, improve soil composition. Although not only phytophages can cause damage, all insect pests of fields and gardens are divided according to the type of food:

1. Monophages - eat only one type of plant, one type of fruit: pear codling moth, Colorado potato beetle.
2. Oligophages eat plants of the same family: cabbage moth, for example.
3. Polyphages eat everything, these include cabbage scoop, locust.

Variety of insect pests

Crop pests are found among many orders:

• Springtails - more than 2000 species have been discovered, are extremely resistant, live in humid places, feed on mold fungi, sometimes undermining the young growth of plants.
• Hemiptera - more than 40,000 species have been identified, all of them feed on plants, sucking juices and leaving a sugary coating on the leaves that prevents the process of photosynthesis. Plants are often infected with viral diseases. The most famous representatives: cicadas, psyllids, aphids, bugs, worms, scale insects.
• Thrips - no more than five thousand species. The order is divided into two suborders, representatives of one of which are phytophages, and the other - predators that destroy smaller pests.
• Hymenoptera - includes the families of sawflies and horntails. Harm forests and forest plantations. Typical representatives are pine sawfly, birch horntail.
• Diptera are represented by flies and mosquitoes. Some representatives perform an important function of pollination. Onion and narcissus flies harm the garden and flower garden.
• Lepidoptera, or butterflies, do not harm plants themselves, participating in pollination. Delayed larvae destroy parts of the plant. Represented by families: scoops, moths, whites, volyankas, corydalis, cocoon weavers, ermine moths, woodworms, glass cases.
• Orthoptera is an extremely numerous order, numbering more than 20,000 species. Among them are the most dangerous pests, for example, locusts. These gluttonous insects are pests of the fields. Locusts are able to fly great distances and gather in huge flocks. Medvedki are no less dangerous, having appeared in the garden, they also massively destroy young shoots.
• Beetles or Coleoptera number 250,000 species. They not only destroy parts of plants, but also affect crops in barns and can cause disease in domestic animals. It is worth mentioning not only what insect pests exist among beetles. Most beetles are predators that feed on classmates. Some benefit by destroying dead organic matter, like the dung beetle. Beetles are divided into many families. Predators include ladybugs and ground beetles. Forest pests include barbels (oak, poplar, willow), lamellar (May beetle, beetle, scale insect), as well as bark beetles. Pests of agricultural crops - weevils, tubeworms, borers and click beetles. The main enemies of the fields are leaf beetles, among which is the famous Colorado potato beetle.

Insect pests of the forest

Pests can also be classified according to the objects they harm. Insect pests of the forest damage trees and shrubs. They are especially harmful to forest plantations and young growth, parks and reserves. They are divided into leaf-eating and those that feed on needles. Infestation of forest areas by pests on the territory of the Russian Federation ranges from 0.1% to 25-29% of the total forest area. For example, the following list shows the maximum damage to forest areas in the European part of Russia, which was occupied by forest pests, for the period from 1977 to 2000.

1. Gypsy moth - 2063.72 ha.
2. Green oak leaflet - 1103.28 ha.
3. Goldentail - 412.2 ha.
4. Siberian silkworm - 0.89 ha.
5. Pine silkworm - 30.18 ha.
6. Silkworm nun - 66.29 ha.
7. Pine moth - 40.22 ha.
8. Pine scoop - 30.97 ha.
9. Red pine sawfly - 113.50 ha.
10. Common pine sawfly - 42.26 ha.

Mass reproduction depends on external conditions and the variety of pests. The outbreak of population increase takes place over seven generations. There are 4 phases during which growth rates may vary. At the beginning of the outbreak, the growth is insignificant, then a steady growth follows, a sharp increase in numbers. After almost all the leaves are destroyed, the growth of the number of insects subsides. The most dangerous are bark beetles, glass cases, horntails, and wood borers. All of them lead a hidden lifestyle in the trunk, gnawing through the passages. This leads to damage to the marketability of wood and drying out of the tree. Forest pests can spread to gardens.

Insect pests of the field

This type of pest causes the greatest damage to the national economy. Among the most dangerous:

Specific crop destroyers

It is difficult to calculate which field pests cause more damage. Cereals are harmed by bread sawflies, some types of thrips, barley moth, green-eyed. Peas and legumes are harmed by aphids, pea leafworms and caryopses, caterpillars of the gamma metal species. The flax worm eats not only flax, but also peas. Hay grasses are mainly harmed by scoops, the larvae of which feed on roots and shoots. Buckwheat is not allowed to develop by a blizzard, a meadow moth. All kinds of leaf beetles cause more damage to garden crops: carrot fly, cabbage moth, cabbage caterpillars and rapeseed sawfly, cabbage weevil. Insect pests of fields and vegetable gardens are numerous. It's hard to mention everyone.

garden pests

In the first place in this group is by no means codling moths. Although they are undeniably dangerous garden pests. Before the crop ripens, buds and ovaries should appear. Multiple insect pests can destroy your garden in early spring. Fruit crops are harmed by:

1. Various weevils and tubeworms laying larvae in buds.
2. Whites, volyankas, cocoons, damaging leaves.
3. Sucking insect pests: aphids, psyllids, mites.

Tree trunks are harmed by all kinds of scale insects (plum, acacia, comma-shaped, apple-tree pseudo-California). Scale insects are named so because they cover their body with a wax shield. Under reliable protection, they feel great, sucking the juices from plants. These insect pests multiply very quickly and within a few hours after the appearance of the larvae, they cover the entire tree. The berries are also harmed by the raspberry beetle, nematodes, glass cases, California scale insects, and raspberry gall midge.

Fighting methods

Ways to protect gardens, vegetable gardens and fields, as well as forests and parks are quite numerous. Annual pest control is as important as soil fertility and moisture. There are both specific methods aimed at the destruction of one type of insects, as well as general ones. Methods are divided into:

• Agrotechnical - these include cleaning fields and orchards after harvest. By depriving insects of a place for wintering, their mass reproduction can be prevented. Breeders are constantly creating new, pest-resistant varieties. Plants need to be planted properly. Keep the required distance. Alternate different types, observe crop rotation. This will reduce the damage that insect pests cause to the garden and vegetable garden.
• Biological methods involve the colonization of agricultural areas by insect enemies. These can be birds and rodents, predatory insects, as well as actinomycetes, bacteria and viruses. Insect pests are eaten by their natural enemies or die from diseases that are harmless to humans and plants. Pheromone traps also belong to biological means of control.
• Mechanical methods involve the manual collection of larvae and insects, as well as the complete removal of infected parts of the plant.
• Physical methods involve the treatment of the affected material with elevated or low temperatures, electric current. Mainly used against barn pests.
• Chemical - are widely used in agriculture, involve the treatment with pesticides and other poisons. No substance is completely selective and harmful to humans and other organisms. To fight with chemical methods, complex technical means are used - aircraft, various sprayers, fumigation chambers. Chemical methods are controversial, but are the cheapest and most effective. After treatment, plant pests will not be able to cause significant damage to your crop. In order to prevent pesticides from getting into agricultural products, pesticides are used for preventive purposes, before fruiting begins.

The wisdom of nature has created mechanisms for regulating the number of species. So, the ladybug feeds on aphids, and birds destroy caterpillars and scale insects on trees. The natural enemies of our enemies will help reduce the number of uninvited guests in the garden. Do not rush to use broad-spectrum chemicals. Not all insects are pests of plants, some can be beneficial.