Mosaic arrangement of leaves. Meaning of leaf mosaic in the Great Soviet Encyclopedia, bse

Leaf arrangement is the arrangement of leaves on a stem.

There are 3 main types of leaf arrangement:

Regular, or spiral,

characterized by the fact that the leaves sit on the stem one at a time, alternating with each other (in birch, apple, rose);

Opposite

2 leaves depart from the node, located one against the other (lilac, yasnotka, mint);

Whorled

3 or more leaves depart from the node (for elodea, crow's eye, oleander). The leaves are placed on the plant in such a way that they do not obscure each other - in the form of a leaf mosaic. This allows more efficient use of the sun's rays. The total leaf area is many times greater than the area occupied by the plant itself.

Layered categories are nothing more than sheet formations, i.e. types of leaves of one shoot, which differ in shape and location on the shoot. There are 3 types of leaves:
- riding - develop in the area of ​​\u200b\u200bthe inflorescence, these are bracts. They are underdeveloped, with a slightly dissected leaf blade, green (may attract pollinators and be brightly colored in this case);
- median - develop in the middle part of the shoot. They are green (perform the function of assimilation), have the largest size, the leaf blade is characterized by the greatest degree of dissection;
- grassroots - develop in the lower part of the shoot. They are white at first, then turn brown as the leaves age, and turn black when they die. They perform the function of protection or storage, or both.

Leaf mosaic- the location of the leaves of plants in the same plane, usually perpendicular to the direction of the rays of light, which ensures the least shading of the leaves of each other.

Leaf mosaic is the result of uneven growth of leaf petioles and leaf blades that reach for the light and fill every lighted gap. In this regard, the size and even the shape of the leaves often change. Leaf mosaic can be observed on horizontal, less often on vertical branches of trees and shrubs in conditions of significant shading (lower branches of the crown of elm, linden, maple), on creeping shoots of grasses (hoof), on rosette shoots (geranium, plantain, dandelion). Leaf mosaic is an important adaptation to maximize the use of diffused light and can be formed in any type of leaf arrangement - spiral, opposite, whorled.

The life span of green leaves developed on shoots varies from plant species to 2-3 weeks to 20 years or more. In general, it should be noted that the leaves of perennial plants, compared with the stem and root, have the shortest life span. This is apparently due to the fact that the leaf tissues, having formed, are no longer renewed, and on the other hand, the leaves function very actively during their relatively short life.

Distinguish plant species deciduous and evergreen. The former are characterized by the fact that annually for a certain period they are in a leafless state, and this period usually coincides with unfavorable environmental conditions. For example, most of our trees and shrubs do not have leaves in winter.

Evergreens are characterized by having green leaves throughout the year. But this does not mean that their leaf is preserved and functions forever, throughout the life of the individual. Evergreens also have leaf fall, but older leaves fall from the plant and the leaves that formed at a later date are always preserved.

Evergreens are characteristic of tropical rainforests, although among them there are plants with leaves that last less than a year. But during this period of time, the buds repeatedly open and give rise to new leafy shoots. In tropical forests, plants with leaves that live for several years are also common. There are plants that, although for a short period of time in the year, may be in a leafless state.

In evergreens near Moscow - spruce and pine - the leaves persist for 5-7 (for spruce) and 2-4 (for pine) years. The life span of spruce needles is longer in plants growing in the Kola Peninsula and the Subpolar Urals, where it reaches 12-16, and in some cases 18 (22) years. The needles of the Tien Shan spruce (Picea scgenkiana F. et. M.) are preserved for a long time in the Zailiysky Alatau, where leaves of 26-28 years of age were found.

leaf fall- a biological process, due to the development of the plant organism and its vital activity. Leaf fall is preceded by leaf aging: the intensity of vital processes occurring in its cells (photosynthesis, respiration) decreases, the content of ribonucleic acid, nitrogen and potassium compounds decreases. Hydrolysis prevails over the synthesis of substances; end products of decay accumulate in cells (for example, calcium oxalate crystals). The most valuable mineral and plastic compounds leave the leaves. Their outflow usually coincides either with the formation and growth of new organs, or with the deposition of reserve substances in ready-made storage tissues. In experiments, it was possible to extend the life of the leaves by removing buds or other formations on the plant, where plastic and mineral substances from the leaves can enter. The transfer of substances to places of their reuse is considered as one of the causes of aging and leaf fall.

Thus, the lifespan of a leaf is determined by the processes of growth and development of the plant organism as a whole.

In most trees and shrubs, during the period of leaf fall, the leaves change color and become yellow or crimson. Their yellow color is due to plastid pigments (carotene and xanthophyll) and cell sap (flavones).

The reddish-crimson color of the leaves is provided by the accumulation of anthocyanin pigment in the cell sap, which changes its color depending on the pH of the medium. In an alkaline environment, the anthocyanin takes on a bluish-blue color, and in an acidic environment, it becomes pink-purple. In some plants (alder, lilac), the leaves remain green until they die.

In addition to the biochemical transformations that occur in the leaves before they fall, anatomical changes are also observed at the base of the leaf. Perpendicular to the longitudinal axis of the petiole, cells of the separating layer are laid near the stem. The intercellular substance connecting these cells becomes mucilaginous, and the cells separate from each other. At the place of separation of the leaf from the side of the stem, layers of cells are formed by this time, the membranes of which are corked. The resulting layer of cork protects the internal tissues of the stem in place of the detached leaf.

After the formation of a separating layer and the disruption of the connection between the cells, the leaf continues to remain on the tree for some time due to the conductive bundles connecting the leaf to the stem. But there comes a moment of violation of this connection, and the leaves fall.

21. types of reproduction of higher plants. Methods of vegetative reproduction

Plant reproduction. One of the essential properties of a living organism is the reproduction of offspring, that is, the ability of one individual to give rise to a whole series of similar daughter individuals, or at least one.

There are two fundamentally different ways of reproduction: sexual and asexual.

Asexual reproduction.

There are two types of asexual reproduction: vegetative and actually asexual. In some lower plants, there is no clear boundary between these types of reproduction.

vegetative reproduction.

It is carried out by parts of the thallus, root, stem, leaf. It is based on the ability of plants to regenerate - to restore the whole organism from its part.

In unicellular plants (algae), vegetative reproduction occurs by cell division, in colonial and lower multicellular plants, by dividing the thallus into parts.

In higher plants, vegetative reproduction is carried out by parts of the root, stem, leaf or their modifications - rhizomes, tubers, bulbs, brood buds. On the basis of natural vegetative propagation in agricultural practice, various methods of artificial vegetative propagation of vegetable, fruit and ornamental plants have been developed. For this, the most commonly used are: tubers (potatoes, sweet potatoes, dahlias), rhizomes (iris, phlox), mustaches (strawberries), bulbs (onions, tulips), root suckers (raspberries, cherries). Many cultivated plants are propagated by cuttings, layering, and also by grafting.

Propagation by cuttings. A stalk is a section of a shoot, root, or leaf cut off from the mother plant. When propagating by cuttings, it is necessary to remember the law of polarity.

shoot cuttings can be winter - without leaves (but with buds), 20 - 30 cm long, at the age of 1 - 3 years, and summer - with leaves, 3 - 4 cm long, from the shoots of the current year.

leaf cutting consists of a leaf blade and petiole. Adventitious roots appear more often on the morphologically lower side of the leaf in places where large veins branch, buds, and then shoots - on the upper side. Only a few plants (lily, begonia, aloe, etc.) can be propagated by leaf cuttings.

Root cuttings propagate plant species whose roots easily form adventitious buds (raspberries, cherries, plums, date palms, roses, phlox, etc.).

Reproduction by grafting. Grafting is the fusion of cut buds or stem cuttings of one plant (propagated) with another (rooted). In this case, the propagated plant is called scion, and the plant to which it is grafted, - rootstock.

About 100 different methods of vaccination are known, but they can be reduced to three main types:

inoculation by rapprochement, or ablactation, - the graft is not separated from the mother plant until it grows together with the stock;

cutting grafting, or copulation, - on annual cuttings of the scion with 2-3 buds and on the stem of the stock, oblique cuts are made and applied to each other, while the stems of the scion and stock are selected of the same thickness so that their cambial layers coincide. If the diameters of the scion and rootstock do not match, then the vaccination is done split, under the bark, butt or in other ways;

inoculation, or budding, - a dormant or growing bud is used as a scion, separated from the middle part of the shoot of the propagated plant, which is inserted under the rootstock bark.

Intergrowth occurs best if the scion and rootstock belong to the same species or close species of the same genus, but if they belong to different genera, intergrowth is difficult.

Having asked a competent botanist or biologist the question of what a leaf mosaic is, we will surely get an answer that will surprise: specify what phenomenon we are talking about. And really, what do we mean?

It turns out that leaf mosaic is an amazing phenomenon and property of plants that mother nature endowed them with. The leaves on the trees in relation to the light flux are arranged in such a way as to receive maximum solar energy, while distributing it evenly to everyone, without shading each other. Thus, leaf mosaic contributes to the maximum use of air, heat flow, space and light by the plant.

Another phenomenon is a complete opposite of the first.

Mosaic, mosaic disease or leaf mosaic. Whatever you call this viral phenomenon, this danger, the severity of the flow and the unenviable fate for the plant itself are unlikely to change for the better.

What is viral leaf mosaic of plants?

This is perhaps one of the most harmful plant diseases. Viruses are to blame for its occurrence and spread.

Moreover, each type of green crop has its own viral enemies:

1. For tobacco and tomato, this is Nicotina virus 1.
2. The emerald coloring of cucumbers is changed by Cummis virus 2.
3. Solanum virus 1 and S. virus 2 are involved in the appearance of speckled and wrinkled potato mosaic.
4. Beta virus 2 is responsible for the beet mosaic.
5. Cabbage, soybeans, peas, beans, ornamental plants, fruit trees and shrubs are “attacked” by Brassica virus 3.

The disease is called leaf mosaic because the leaves of the plant are the most vulnerable and suffer first.

If we do not take into account the severity of the disease and the lethal consequences for green culture, then the mosaic color of the leaf looks fun and funny, and in some way, even aesthetically pleasing and beautiful.

The variegated coloring of the affected leaves is striking - the alternation of spotty formations, different in shape, size and intensity of green.

Viruses, regardless of their type, kill the culture at the cellular level. The fundamental pathology manifests itself in chlorophyll-bearing tissues, which leads to a decrease in photosynthesis. The foliage does not receive the required amount of carbohydrates, cells and entire sections of leaf tissue die off.

Varieties and ways of spreading the disease

In the previous section, we discussed viruses that provoke mosaics in certain plants. According to the names of crops, varieties of garden misfortune were formed.

The greatest harm and danger are mosaics of fruit trees and shrubs, tomatoes, tobacco, beets, cabbages, soybeans, peas, white and green cucumber mosaics, speckled and wrinkled potatoes, as well as ornamental plants, especially.

Rose afflicted with mosaic disease

It should be noted with regret that the number of communication channels for the spread of garden infection is very large. And the big problem is to completely block them.

The pathogenic virus easily penetrates through planting material, seeds and infected seedlings, during picking through the sap of diseased plants, during pinching, with direct contact between infected and healthy individuals, and also during banal injury.

All is well if gardeners were only concerned with these problems. However, viruses still have enough helpers, a kind of mobile vehicles - these are ticks, aphids, bedbugs. Moving around the site, they easily spread the mosaic pest.

It should be noted that a comfortable environment for the development of the virus is the density of plants, temperature drops at maximum readings of over 25 degrees.

How to recognize the disease?

It is easiest to notice the pest on young shoots.

Typical visual manifestations:

1. Mosaic leaf spot, which changes their structure.
2. Spots of irregular shape, different in size and color - from whitish to light yellow and bright green.
3. Pathology in development is noted, plant growth slows down.
4. The access of water is reduced - the culture becomes limp and withers. New shoots and stems that have just appeared begin to dry out.
5. The fruits are covered with brown spots, which turn into rot. They are not suitable for fodder even for livestock.

Depending on the type of green crop, mosaic disease has exclusive features.

Fruit trees - it has been noticed that the pear is the least protected genus of fruit crops from the virus.

Signs of defeat:

1. The bark and large branches are scarred.
2. Foliage, especially young ones, is covered with "camouflage" spots.
3. Rigid formations appear in the depth of the fruit, it changes shape, the core turns brown, rots, the yield is significantly reduced.

Pear leaf affected by disease

Mosaic on flowers:

1. The leaves are cut with yellow arrows and brown lines.
2. The buds are shrinking, not having time to bloom and complete flowering. The flower itself withers, drying up, fading and dying.
3. The flowering period is unusually short or does not start at all.

Mosaic on berry bushes - almost all varieties of raspberries suffer, most currants, gooseberries, grapes.

Visual symptoms:

1. Leaf chlorosis is clearly visible - violations in the formation of chlorophyll. The foliage is discolored, losing its characteristic green color.
2. In appearance, the plane of the sheet seems to be scorched. Edges and corners are curled.
3. Young shoots are significantly stunted.
4. Soon the virus completely disfigures the bush. It is decorated with yellow-brown spots of various sizes.

Potato mosaic disease:

1. Longitudinal stripes appear on the stem and upper crown.
2. The bush slows down growth. Leaves become rough and shrink.
3. The disease, tending down, strikes the roots. The tubers change shape, as if turning out. They lose their taste and are unsuitable for food.

Tomato mosaic is the most common misfortune for this culture. In the people it is called a burn of tomatoes.

External manifestation:

1. The foliage is torn with a spotted color.
2. Dark green and light formations appear on the fruits.
3. The tomato is deformed, the inside turns black and rots.

Mosaic tomato disease

Mosaic ordinary on cucumbers:

1. At an early stage of the disease, the stems of the seedlings are bent, the leaves are covered with mosaic spots.
2. As the disease progresses, they dry out and curl.
3. The number and size of flowers are significantly reduced.
4. With a strong defeat, the flowers dry up without completing the entire cycle.
5. The stem becomes faded or almost transparent, cracks appear on it.
6. The fruits are twisted, covered with yellow and brown spots.
7. The bush, drying up, fades before our eyes.

Cucumbers affected by mosaic disease

Virus on cabbage

1. The veins on the leaves lighten up.
2. Black spots are formed, characterizing necrosis.
3. The leaf loses its shape and wrinkles.
4. The stem rots, becomes brittle and unstable.

Black spots on a head of cabbage - a sign of a mosaic disease

It is worth noting that there are no such varieties of cabbage that would resist this natural ailment.

Disease on peas and beans:

1. The leaves take on a curly, crumpled shape.
2. Spots of whitish and yellow color are formed on the surface.
3. After the disease of the stem, rosettes of diseased leaves appear on the lower tier.
4. Plant growth slows down significantly.
5. Yellow and brown spots scatter on the pods. They blacken and rot.

Mosaic on radish and radish:

1. The sheet is covered with a mosaic scattering.
2. Its shape changes, the veins darken.
3. Growth slows down significantly.
4. Black spots appear on the root crop, which turn into rot.
5. The fruit is small and unsuitable for food.

Fighting methods

In the fight against the disease, the most unpleasant thing is that science has not yet been able to offer effective remedies. Each gardener or gardener uses his own experience or recommendations taken from various sources or communication with colleagues.

If the infection is local, then partial removal of diseased areas is used. To do this, cut off diseased parts (branches, shoots) with a disinfected knife. After such an operation, the entire plant is sanitized by making a solution of ten liters of water and 75 grams of Karbofos.

The cut points can be treated with a different composition - mix a weak solution of potassium permanganate with crushed charcoal.

But if we are talking about the defeat of a large area, then there is only a radical way - diseased plants are removed and burned.

After diseased plants are destroyed, remove and dispose of the soil to a depth of 10 centimeters.

If viruses have taken over the greenhouse, then after removing all crops, carefully disinfect using a half-percent solution of trisodium phosphate.

It will not be superfluous to thoroughly process and boil the clothes in which you carried out the treatment, since the virus can be in a "sleeping" state for many more years.

Prevention

As it becomes clear from the previous section, in view of the fact that scientists have not yet proposed effective means of combating leaf mosaics, the main hopes are placed on preventive measures in order to minimize the reproduction of harmful viruses in your farmstead.

1. Purchase planting material only in reliable specialized stores.
2. Carefully study the characteristics of planting material, trying to select varieties resistant to the virus.
3. Considering that different types of garden crops are susceptible to infection with different viruses, then alternate them between planting seasons in greenhouses and in open areas.
4. Carefully remove remaining plants from greenhouses and open ground. Especially when it comes to sick specimens.
5. Clean the soil in the greenhouse to a depth of ten centimeters, and in the spring replace it with new, cultivated soil.
6. Do not chase after saving the landing area. Dense beds are an ideal habitat for a garden enemy.
7. When caring for plants (garter), do not use last year's twine.
8. When removing diseased plants, treat the soil with bleach. With the same solution, rinse the garden tools that were used to remove infected crops.
9. Plan your garden beds carefully. Avoid close planting cucumbers with ornamental plants.
10. Remember that carriers of viruses are aphids, bedbugs,. Therefore, take preventive measures to destroy them.

Viruses that cause plant mosaic disease are a dangerous, hidden and insidious enemy. Dealing with them is difficult, but possible. Diligence and diligent implementation of all recommendations - this is the key to victory over garden enemies.

LEAF POSITION, LEAF MOSAIC.

Leaf arrangement, or phyllotaxis, is the order in which leaves are placed on the axis of the shoot. Patterns of leaf placement are associated with the activity of the shoot apex and reflect its radial symmetry. They are sometimes quite complex in nature. In descriptive morphology, when characterizing leaf arrangement, they are most often guided by the number of leaves extending from one leaf node. There are three main types of leaf arrangement (Fig. 53): spiral, or alternate, when one leaf leaves each node of the stem (oak, birch, cereals, umbrella, etc.), opposite - when two leaves sit opposite each other on each node (maple, lilac, labial), and whorled - when each node carries three or more leaves (oleander, villain).

The leaf position of the adult shoot is determined by the order of laying of the leaf primordia. This is a hereditary trait. Sometimes whole families are characterized by a certain type of leaf arrangement.

Rice. 53 Modifications (metamorphoses) of the shoot:
1 - ordinary elongated shoot, 2 - fleshy shoot of a cactus with reduced leaves, 3 - onion bulb, 4 - mustache (modified inflorescences) of grapes, 5 - green leafless photosynthetic shoot of gorse, 6 - couch grass rhizomes, 7 - phylloclades of needles, 8 - thorn honey locust, 9 - potato tuber

In the process of shoot growth, its leaf arrangement may change. In addition, the petioles of the leaves can be bent, and because of this, the position of the blades also changes. In this case, the blades of all leaves are eventually located, not shading each other, but forming a single plane, where the gaps between large leaves are filled with smaller leaves. A similar phenomenon, called leaf mosaic, allows the plant to more fully use the sunlight falling on it.

FEATURES OF SHOOTS GROWTH AND SHOOTS TYPES DEFINED BY THEIR POSITION IN SPACE. FORMATION OF SHOOTS SYSTEMS.

Monopodial growth of shoots in length is carried out due to apical buds, and the formation of lateral sympodial shoots occurs due to lateral (axillary) and accessory buds, which ultimately creates a system of shoots and determines the appearance of the aerial part of the plant, i.e. its habitus.

In the seasonal climate of the temperate zone, the development of shoots from buds in most plants is periodic. In shrubs and trees, as well as most perennial grasses, buds “unfold” into shoots once a year - in spring or early summer, after which new wintering buds are formed with the beginnings of next year’s shoots. Shoots that grow from buds in one growing season once a year are called annual shoots. In many tropical and subtropical plants that live in a climate devoid of sharp seasonal differences, there is still a rhythmic growth of shoots separated by small dormant periods. Such increments, formed in one growth cycle, cannot be called annual, since there are several of them in a year. Such shoots are proposed to be called elementary. In many perennial grasses, annual and elementary shoots are not clearly demarcated.

Depending on the degree of branching of the shoot system, non-branching, weakly branching and strongly branching plants are distinguished. Some woody plants of the tropics, in particular palm trees, do not branch or branch weakly. Some annual herbs branch weakly in dark conditions. Most plants in temperate countries branch profusely. Plants that form life forms such as tumbleweeds and cushion plants branch most strongly.

The main shoot in most cases has an orthotropic growth (upright shoot). Side shoots can grow in different directions, both orthotropic and plagiotropic. Sometimes the main shoot initially grows plagiotropically, and then changes the direction of growth to orthotropic. In this case, they speak of rising, or ascending, shoots. Shoots with plagiotropic growth that persists throughout life are called creeping shoots. If they form adventitious roots that penetrate into the substrate, they are called creeping. Differences in the growth of shoots are closely related to the features of their functioning.

Orthotropic growth is in a certain way related to the degree of development of mechanical tissues. In the absence of well-developed mechanical tissues in elongated shoots, orthotropic growth is impossible. But often plants that do not have a sufficiently developed skeletal system of mechanical tissues still grow upwards. This is achieved in various ways. Quite often, weak shoots of such plants twist around some kind of solid support (curly); cling with the help of various kinds of spines, hooks and suckers (clinging); or climb, wrapping their antennae around solid supports (climbing).

In the same plane, usually perpendicular to the direction of the light rays, which ensures the least shading of each other's leaves.

Leaf mosaic is the result of uneven growth of leaf petioles and leaf blades that reach for the light and fill every lighted gap. In this regard, the size and even the shape of the leaves often change. Leaf mosaic can be observed on horizontal, less often on vertical branches of trees and shrubs in conditions of significant shading (lower branches of the crown of elm, linden, maple), on creeping shoots of grasses (hoof), on rosette shoots (geranium, plantain, dandelion). Leaf mosaic is an important adaptation to maximize the use of diffused light and can be formed in any type of leaf arrangement - spiral, opposite, whorled.

Role in plant life

Leaf mosaic- a phenomenon in which the leaves are located in space on the shoots of one plant in such a way that their plates do not obscure each other. Leaf mosaic allows the plant to more rationally use the sunlight falling on it. Sheet mosaic:

• causes the formation of light and shade effects under the crown of the tree;
• gives picturesqueness and originality to the appearance of the plant.

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An excerpt characterizing Leaf Mosaic

How to recognize the disease, its manifestations

Mosaic is a disease whose main characteristics are patches of green and white on leaves and fruits. They come in different sizes and shapes, cause damage to the leaves and change their contour.

Seedlings affected by infection slow down development and growth, and adult plants gradually wither and die. Before the characteristic spots appear, entire fields can be completely infested.

History of appearance

As early as the end of the 19th century, the first symptoms were found on tobacco plantations. At first, one bush was infected, it became covered with bright marks, lost its shape and eventually died. Gradually, one by one, neighboring ones fell ill, and soon, entire plantations were unsuitable for further tobacco production.

The only way to fight at that time was the destruction of infected seedlings at the first manifestations in order to save the rest. The disease was called "tobacco mosaic". Only a century later, Dr. Ivanovsky D.I. A virus that causes mosaic disease in plants has been discovered.

What caused

Mosaic completely affects tissues at the cellular level. Occurs as a result of damage to chloroplasts and partial destruction of chlorophyll. There is a breakdown of plastids, as a result of which the level of carbohydrates decreases. The death of individual sections of tissue begins. Pathogens named Nicotina virus 1, Cummis virus 2, Solanum virus 1 and many others.

How does it manifest

There are many viruses that infect only certain varieties. On garden crops, the mosaic can be expressed in different ways. The first manifestations characteristic of it are:

• Spots of different colors and sizes: they can be light yellow, bright green or whitish. They have an irregular shape and deform the structure of the sheet plate.
• The development of the culture slows down, in comparison with the rest, the water exchange is disturbed, due to which the stems and leaves dry out. First of all, this applies to young shoots.
• Brown spots on vegetables and fruits. Due to damage, the process of decay begins, so they become partially or completely unsuitable for food.

How it spreads

Infection can occur through mechanical damage during processing or normal contact with infected crops. Often this happens when diving dense seedlings. But the disease can also be transmitted by touching foliage or stems with each other from the wind.

Trimming and breaking off infected leaves or stems is not recommended, as the juice remains on the blade and hands. With further work on the site, there is a possibility of multiple infection.

The disease can be spread by carriers. They can be insects such as: aphids, ticks, bugs, etc. Also, the mosaic is transmitted through fruits and seeds carried by birds and animals.

The soil below the root is a breeding ground for infection, as plant debris, such as leaf litter, can remain in it. High humidity and air temperature + 20-25 ° C contribute to the development of mosaic infection.

Spread can also occur through raindrops flowing down the infected plant with small particles of diseased plants.

Main affected crops

Unfortunately, the mosaic has many varieties and affects almost all agricultural and horticultural crops. It is possible to get rid of it or prevent its spread only at an early stage. It is necessary to identify diseased plants and destroy them in order to keep healthy ones.

On fruit trees

The causative agent is subcutaneous spotted mosaic. Most often, the pear suffers. Signs of damage to fruit trees:

• cracks in the bark and main branches;
• the foliage is covered with mosaic spots;
• hard clusters form in the fruits, the shape changes, the flesh darkens;
• yield drops sharply.

On flowers

The mosaic appears as follows:

• yellow arrows and lines appear on shoots and stems;
• flowers become small, lethargic, acquire a greenish tint, most of them fall off;
• the flowering period ends faster than usual.

The disease is easily transferred to neighboring rose bushes, destroying entire plantings and beds.

Berries

They are affected by vein mosaic. Character traits:

• chlorosis of the leaf veins (marks of different colors), folding of the edges, the leaves become as if scorched;
• the development of young shoots is reduced;
• affects the entire bush, covering with yellow spots of an angular shape.

Many varieties of raspberries and other fruit and berry crops, such as currants, grapes, gooseberries, etc.

Potato

Potato bushes are struck by such a type of mosaic as striped. The first characteristic manifestations:

• longitudinal stripes are clearly expressed on the upper tissues and stems;
• they become rough and decrease in size;
• affects the tubers, they become spindle-shaped.

As a result, potato fruits lose their taste, and the yield index decreases. The striped mosaic affects the entire plant and leads to its death.

tomatoes

Tomato mosaic is the most common disease of this species. It is also called burn. Characteristic signs:

• The leaves acquire a bright spotted color;
• light and dark green marks appear on the fruits;
• deformation and blackening of the pulp of tomatoes, followed by decay.

Because of the mosaic of tomatoes, you can lose up to 20% of the crop. That is why for planting it is necessary to use only high-quality and healthy seeds.

cucumbers

Cucumbers are most commonly infected with common mosaic. Symptoms:

• curvature of the stems and spotting of the leaves while still in seedlings;
• over time, they dry out and curl up;
• cracks in the stems;
• the number of flowers and their size decreases;
• cucumber fruits are often curled up and covered with yellow spots.

With a strong lesion, the flowers may dry out, and the stem becomes almost transparent or faded. The whole bush loses color and fades.

Cabbage

Manifestations of cabbage mosaic:

• the veins become lighter;
• dotted spots of necrosis appear;
• fabrics lose their shape and wrinkle;
• the stem becomes brittle and breaks easily.

It affects almost all types of cabbage.

Radish

Both radish and radish are exposed to viral damage. Symptoms:

• mosaic, change in shape, darkening of the veins;
• growth retardation;
• the appearance of black spots on vegetables, small fruit.

It can be expressed differently in different varieties.

Peas

It is more often affected by the deforming mosaic virus, occasionally by the common one. Appears in:

• bruising and curliness of fabrics;
• white and yellow markings on leaves;
• growth retardation;
• spotting of pods, their decay and blackening.

Peas in pods turn yellow.

Beans

It is affected, most often, by an ordinary mosaic. Symptoms:

• the foliage is covered with irregularly shaped spots, spinning and bubbling;
• the stem is affected, and a rosette of diseased leaves is formed below;
• seedlings remain dwarfed.

The roots are infected along with the soil below them. The fruits have an unhealthy faded color.

Methods of prevention and protection

The very first and most effective remedy for any disease is prevention.

Prevention methods

To initially exclude the possibility of mosaic infection and get a good and healthy harvest, you should:

• use only healthy material for planting;
• fight insects that are carriers of the mosaic by performing spring garden processing;
• choose varieties that are more resistant to infection;
• destroy infected units along with the ground from under the bushes;
• plant sprouts as far apart as possible;
• clear plantings from weeds;
• disinfect the blades of garden tools (with a solution of vitriol - 4 tablespoons per liter of water or potassium permanganate - 2 tablespoons per liter of water).

Prevention for seeds

When buying seeds, it is quite difficult to determine their quality. Also, you cannot be sure that they are healthy. Before planting, seeds can be prevented by keeping them in hot water for half an hour, or disinfected in a 20% hydrochloric acid solution. Then the seeds should be washed and dried.

Treatment

There are no cures for mosaic, as such. The only effective treatment is the destruction of infected bushes and weeds, the fight against insect vectors.

To disinfect scissors or pruner blades, you can use alcohol (both medical and ordinary vodka is suitable) or a chlorhexidine solution. Carrying out the trimming procedure, after each use of the tool, wipe the cutting surface with a cotton swab or cloth soaked in a disinfectant liquid. Be very careful not to break the stems when tending or cultivating the lawn.

If the mosaic has just begun to develop, you can treat all the bushes with a solution of karbofos. To prepare it, dilute 75 g of the drug in 10 liters of water and spray the plantings. This will help protect healthy crops from infestation. Heavily damaged bushes should be removed immediately.

If the cultures in the greenhouse were affected by the mosaic, then after harvesting it is necessary to remove all the plants together with the top layer of the earth (up to 10 cm). Then carefully treat the entire greenhouse (including the walls) with a 0.5% solution of trisodium phosphate. Clothing that you disinfected should also be thoroughly boiled and cleaned, as the mosaic virus can remain on it for several more years.

Outcome:

Mosaic plant disease is quite common. The causative agents are viruses, for which there is no cure yet. The only way to fight is prevention.

To date, selectors are actively working on resolving the issue. Their main task is to develop mosaic-resistant varieties of crops, which will eradicate the infection and increase plant yields.