Why is mosaic disease dangerous and how to save plants from it?

Mosaic is a disease of garden and garden plants. The danger of a viral infection is that, without recognizing it in time, you can lose the entire crop. At the same time, there are still no effective drugs for the treatment of this particular disease. Prevention and increased control of any changes in plant development are measures that can protect plantings from mosaic viral infections.

Disease symptoms

The first signs of a mosaic are observed on the leaves of seedlings or young greenery of seedlings. Against the background of the main color, spots of a lighter shade appear, light brown, yellow, up to almost white. Irregular specks cover the entire leaf plate with a mosaic pattern, which gave the name to the disease. The greater the number of spots and their size, the more noticeable the deformation of the affected parts, the inhibition in the development of the plant. Gradually, the culture withers, dries up and dies.

At the cellular level, the mechanism of action of the virus is as follows:

1. The causative agent of the mosaic destroys plastids - little bodies in the structure of plant cells. These specific organelles are responsible for photosynthesis - the basis for plant vitality.
2. By destroying the plastids, the virus leads to the degradation of the culture. The level of chlorophyll and carbohydrates decreases, water exchange is disturbed. The plant is not just incapable of further development - it dies.

The mosaic damages all aboveground and underground parts. Fruits affected by the virus are unfit for consumption. Signs of a mosaic on the crop - dark to brown-black spots, deformation, decay.

The spread of the virus

Favorable conditions for the spread of the virus are warm rainy weather. The viability of the pathogen of the mosaic obliges farmers to carefully observe the hygiene of gardening and horticulture.

Viruses are transmitted by contact, and the source is any object that has come into contact with an infected culture:

• Plants with a thickened planting transmit the virus to each other.
• Seeds from the affected garden, vegetable garden, ornamental crops store the pathogen in the shell and core for several years.
• Infected soil introduced to the site becomes a breeding ground for disease.
• Birds, animals carry the virus with feathers, wool, and waste products.
• Pest insects, moving from one crop to another, spread the mosaic.
• Country tools, protective equipment, clothing, after contact with infected plants, retain the virus for several seasons.
• The pathogen wanders with the wind, rains, that is, there is no guarantee against the penetration of infection into a small summer cottage or agricultural land of large organizations.

For the first time discovered on tobacco in the 19th century, the disease received the corresponding name - tobacco mosaic. Originally common on related nightshade crops, the infection has taken on many forms over time. The danger of mosaic diseases is aggravated by the fact that the virus inhabits any plant species, it has no dependence on a specific culture.

Manifestation in different cultures

Since the only way to stop the spread of a mosaic that has already begun is to destroy the affected areas of the plants, you need to know additional symptoms in different crops.

Nightshade

In open ground, greenhouses, greenhouses, tobacco mosaic affects representatives of the Solanaceae family:

• tomatoes,
• peppers,
• eggplant,
• potatoes,
• tobacco.

As a result, crop losses amount to at least a fifth.The leaves of infected plants are covered with a pattern of light green, then yellow spots.

Dense leaf plates on tomato bushes become thin, brittle. Spots, spilling out, form multiple holes. The tops of the bushes curl up, the petioles and shoots are covered with black specks - the development of the plant stops. Brown netted spots, penetrating deep into the fruit, cover the berries.

The combination of yellow and white spots on the leaves and black streak marks on the shoots and petioles gives a mosaic on the peppers. Leaves curl, crumble. Brown dents appear on the fruit.

A striking example of the leaf form of the disease is tobacco. The leaf plate, covered with a mosaic pattern of light yellow and white tuberous spots, deforms and becomes thinner. Drying specks fall out, turning the leaf into "lace".

Potatoes are susceptible to several types of mosaic virus at once:

• The wrinkled mosaic is manifested in the first year by the tuberosity and disproportionality of the leaves curled at the edges. Affected plants lose their ability to retain moisture in their tissues, so any drought destroys them. Infected tubers produce weak tops that are incapable of normal development. The result is a loss of more than 90% of the crop.
• A streaky mosaic infection ascends the plant from the lower leaves. Necrotic spots and narrow dark stripes along the veins on the tops are a sign of a streak (this is also called this type of disease). The affected leaves fall off, the degradation of the bush reaches the crown. As a result of the inability to photosynthesize due to wilting of the tops, the plants die. Crop losses - from 90%.
• Ordinary speckled mosaic - leaf plates and veins are highlighted. Severe forms lead to necrosis of the pale areas of the tops. Plants with good immunity cope with the causative agent of the disease on their own. Up to a quarter of the crop dies from this virus.

Infected tubers have stripes or dark circles in the cut. There is no point in planting infected potatoes, since the plant is not able to develop normally.

Cucumbers

Common, speckled, white - these types of mosaics are most common on cucumbers. Discolored dots that grow over time cover the entire leaf plate with spots. The growth of the bush slows down, flowering and fruit setting stops. Already grown fruits are deformed, become spotty and bumpy.

Plants weakened by temperature changes and uneven watering cannot withstand viral infection. Mosaic diseases of cucumbers develop rapidly in greenhouses: in greenhouse conditions, the virus is carried by insects, spreads by contact of leaves of neighboring bushes.

Fruit crops

Garden plants are more likely to be attacked by a virus - the causative agent of subcutaneous mosaic.

Signs of the disease:

• characteristic spotted pattern on foliage,
• cracking of the bark,
• deformation of the fruit.

Mosaicity of the pulp is manifested by the appearance of simultaneously compacted and softened areas.

Berry crops

Mosaic infection on berry crops manifests itself as follows:

• shapeless angular stars of spots cover leaves, twisted, as if from a burn;
• young shoots stop growing;
• flowering and fruiting is reduced.

The vein mosaic virus is able to destroy raspberries, currant and gooseberry bushes, vineyards.

Ornamental crops

Most types of flowers, annuals and perennials, catch the infection carried by insect pests.

• Young shoots are covered with a net of streaks, the flowering time is reduced.
• Sluggish weak plants lose buds and inflorescences.

In densely planted flower beds, the virus is quickly transmitted from one specimen to another.

Houseplants

If a virus appears at the summer cottage, then there is a risk of bringing it home.

Mosaic gets into the house in different ways:

• with collected fruits;
• with cut flowers;
• on the skin and clothing;
• with the ground;
• with flying insects.

The virus spreads easily to indoor flowers. Symptoms are the same as in most crops: overgrowing leaf blight eats away at plant tissue. Failure to photosynthesize in the required volume, to maintain water balance, leads to weakening of flowers, growth retardation, and loss of decorative effect. Not adapted to a lack of moisture in dry room air, they quickly fade.

Florists who have had to deal with mosaic diseases of indoor flowers emphasize that the virus is carried by pests, tools, pollen and even on the hands when working with different crops. It is impossible to cure, for example, hippeastrum from the virus of leaf tobacco, cucumber, ordinary mosaic. The disease develops over the years, moving from the leaves to the bulb.

Prevention of the disease

Protection of plants from the mosaic virus - strict adherence to the advice of agricultural technicians, the implementation of preventive measures:

• disinfection of garden tools, tools (a strong solution of potassium permanganate is used);
• planting virus-resistant varieties;
• sowing of treated seeds, seedlings, tubers, bulbs;
• disinfection (steaming, spilling with hot potassium permanganate) of planting soil for seedlings;
• disinfection of greenhouses, greenhouses (sulfur checkers, hot spillage of soil);
• treatment with Bordeaux liquid of the site in early spring and before winter;
• weed and pest control;
• compliance with crop rotation, planting technology, care;
• regular inspections of crops for virus damage, immediate destruction of plant parts with suspected mosaic;
• cleaning of all plant residues at the end of the season.

Strong, strong plants, obtained with care and proper care, are able to resist the attacks of the virus. Therefore, all of the above measures are a reliable means of protecting plantings from the most dangerous disease.