Viral diseases of indoor plants - control and prevention. Causes and symptoms of the disease


Sometimes you grow a flower, grow it, and then suddenly you notice that its leaves are rapidly beginning to turn yellow, become stained or fall off. And while you figure out what's what, half a flower has already disappeared. Moreover, interestingly, the flower itself did not seem to die, but stems and single leaves remained from it. And viruses and fungi that infect indoor plants are to blame for all this.
Why viruses and fungi are insidious? Just like in the human body, they multiply very rapidly in the body of a plant. And more recently, a healthy flower looks completely sick in a couple of days. It is not surprising that the onset of a viral illness is easy to miss. Therefore, it is better to know in advance about the various types of viruses and fungi that infect indoor plants.

Causes and Effects

Before talking about the viruses and fungi themselves, I propose to first understand the reasons for their appearance. After all, any microbe or fungus starts up only under certain conditions. Which ones?

The conditions under which plants become infected with viruses or fungi are individual for each plant. But the main reasons are violations in flower care. That is, if you expose shade-loving flowers to the sun, and fill them with moderate watering, you weaken their immunity. And here, as in humans, a plant with a weakened immune system is more easily affected by viruses and fungi.

Where do they come from? Viruses often carry pests that grow on flowers. The same thrips, aphids, house ants on their paws carry various types of infections.

The soil can be infected with viruses, so after buying the soil it is better to ignite it over a fire or at least pour it with potassium permanganate. And the spores of various fungi are easily transported through the air.

Viral plant diseases

I have already said above, but I repeat - these are the most insidious diseases of indoor flowers. They are difficult to detect at the initial stage, and there is NO cure for them!

What does a plant that has caught a virus look like? However, there are not very many viral diseases of flowers and their symptoms are similar. The main symptom is changes in the structure and color of the leaves, as well as various spots, streaks, stripes and zigzags on the leaves and flowers.

Mosaic disease

One of the types of viral flower disease is Mosaic disease. Spots of different sizes and shapes appear on the leaves - like a mosaic. And mixed with spots, you can see multi-colored arcs, lines, stripes, winding lines, rings. In these places, the color of the leaf is changed. And the structure of the sheet can look unnatural. Curliness and wrinkling of the surface appear.

Such a mosaic coloring does not harm the plant too much, but the flower looks at the same time unaesthetic. Pelargonium, primrose, feces, begonia suffer the most from this scourge.


But this virus is more dangerous than the one that causes mosaic patterns. He is very oppressive to the plant. If the flower has caught the Jaundice virus, then this can be determined by the fact that the plant is withering, slowing down in growth. Visually, this can be seen in the clearly yellow leaves and flowers of an ugly shape with a changed color of the petals.

You can read more about Jaundice in the article
Jaundice of flowers

Jaundice is dangerous because it affects the entire vascular system of the flower. His cells die because this virus causes hypertrophy of the sieve tubes. There is no complete metabolism of nutrients in the plant's body. The leaves of the plant become hard to the touch, brittle, as excess starch accumulates in them. It happens that spots similar to mosaic appear.

This virus is very dangerous, so it is better to destroy the plant so that neighboring flowers do not get infected.

Curly leaves

When a flower has naturally corrugated, double or curly leaves, it is beautiful. But if suddenly smooth leaves become so, then this is a disease. The curliness of the leaves appears at first in the form of small specks (1-2 mm). They dry out and the leaves become wrinkled (curly). Flowers also become deformed. Later, spots or lines of gray-white or yellowish color may appear. Pelargonium, poinsettia, primrose suffer the most from this virus.

Treatment of viral diseases

If the plant is not yet too infected with the virus, the affected shoots and flowers can be cut off. By the way, the tool then needs to be treated with alcohol. It is advisable to transplant by disinfecting the soil. But it's not a fact that this will help - viruses are very insidious. And in the case of jaundice, the plant is generally almost impossible to cure, since the disease affects the vascular system of the plant.


  1. Plant Disease Information

Sections: Diseases Diseases of indoor plants


The main symptom of plant damage by viral diseases is a deterioration in growth, so a diagnosis is usually made of a lack of nutrition and unfavorable living conditions. In addition, viruses are difficult to identify immediately because the plant rarely dies.

Most often, viruses are carried by pests - aphids, thrips, etc. Fungal spores can also carry or implant viruses into cells like a Trojan horse. The numerous viral diseases known to date, the so-called viroeas, get their name from the main host plant that they infect. At the same time, external signs of damage often appear in the name, such as, for example, the mosaic tobacco virus, which indicates that light spots similar to a mosaic appear on the plant. Externally, damage caused by viruses on indoor plants can look very diverse. Your houseplants will have stunted leaves or plant growth as a whole (tuft growth). Also noteworthy is the deformation of leaves or flowers. The flowers may show discoloration, such as intermittent color, but the plant itself will not die. The most typical manifestation of viroses is the appearance on leaves and stems of spots, stripes, dashes of varying intensity, or lightened areas of tissue in the form of spots or rings.

Treatment: it is a pity, but no drugs for the treatment of viral diseases in plants still exist. Plants affected by virosis are destroyed. If a plant sick with virosis does not look very ugly, it can even be left to grow by removing the parts that spoil the appearance. However, in this case, there is a serious risk of infection due to the appearance of insect pests that carry viruses. A diseased plant can infect other plant species! In each case, decide for yourself what to do with the diseased plant.

Mosaic of leaves and flowers


Bacteria usually enter plants through lesions or through holes in the leaf, which are used for breathing or excreting water. Inside plants, bacteria can spread through conductive vessels, the purpose of which is to transfer nutrients and strengthen shoots. The multiplication of bacteria there leads to various diseases that manifest themselves in the form of wilting (in combination with black stripes on the stems, cracked shoots and hollow stems inside). However, the spread of infection is also possible in plant tissues, since bacteria can dissolve cell membranes, which leads to tissue decay.

Both of these symptoms are just two examples of the external manifestation of plant damage by bacterial diseases. Root rot, when bacteria penetrate through the soil, begins with rotting of the root collar, gradually rot spreads to the entire root system. Most often, cyclamens, dieffenbachia, saintpaulia and sansevieria are affected.

Another significant sign of damage is wilting, yellowing and falling off of leaves, which is more often observed in pelargonium. On the leaves of begonias, pelargoniums and ivy, you can sometimes see light oily spots that quickly grow in size. This oily spot is a bacterial disease that can also spread to stems and flowers.

When affected by some types of bacteria, the formation of mucous secretions can be observed.

A variety of tumors and neoplasms (the so-called bacterial cancer) can also be a symptom of a bacterial disease. More often it affects the roots and root collar of begonias, succulent milkweed, Kalanchoe and oleanders.

Direct control of pathogens of bacterial diseases with chemical preparations is prohibited and does not give positive results at home.

It is recommended to carry out preventive measures. Root decay occurs from overdrying an earthen coma or waterlogging. If root decay is detected, the moisture of the earth is reduced and watered with warm water.
If the entire plant is affected, it must be completely destroyed along with the pots and soil. They keep diseased plants in a dry place, do not spray with water and do not wash in the shower.



Dropsy is a disease caused not by a fungus or bacteria, but as a result of waterlogging of the soil with a lack of lighting. In a diseased plant, cork growths form on the underside of the leaf. The affected leaves will no longer recover, but if the plant is in good conditions, then after a while new leaves will appear.

Signs of the disease: dense cork growths on the underside of the leaves.

removal of diseased leaves, after which the plant is transferred to a brighter place and watering is reduced.


A non-communicable disease characterized by inadequate chlorophyll production.

- lack of mineral elements

Signs of the disease are light yellow spots on the leaves.

Treatment consists in improving the care of a sick plant, feeding, and when the plant gets stronger, transplant. In this case, the plant should be placed in a well-lit place, as close to the light as possible.

Improper care

The most common reason for yellowing the leaves of indoor plants is improper care. As soon as the plant is in the wrong conditions, it begins to lose leaves, which over time can lead to its death.

Let's take a closer look at the main reasons why a leaf can turn yellow and lethargic:

  • Insufficient watering. If the earthen lump is dry, the leaves first become lethargic and sag due to a decrease in turgor pressure in the plant cells, and then begin to turn yellow and dry out. Some indoor flowers are very sensitive to drought - it is enough to skip watering once, and the leaves will already begin to turn yellow.
  • Excessive watering. If the flower is watered too often, a similar effect will be observed, as the roots will begin to rot. The first sign of excessive watering in many plants, for example, in spathiphyllums, is dry leaf tips: they first turn yellow, and then they can turn black. Excessive watering at low room temperatures is especially dangerous.
  • Indoor air is too dry. Many indoor flowers grow wild only in the tropical zone, where it is almost always hot and the air is humid. If you do not provide the plant with proper conditions, it will always feel bad.
  • Drafts or cold air flow from an air conditioner. This is another common cause of yellow leaves. Plants should not be left near half-open window sashes, especially when ventilating the room during the cold season.
  • Insufficient illumination. In this case, the plant gets rid of leaves that are not exposed to sunlight, especially hibiscus. It is advisable for light-loving plants to find a place on the south or east side of the house.
  • The problem of yellowing of leaves can also occur due to improperly selected fertilizers. Iron chlorosis often occurs - a disease in which the leaf itself turns yellow, and the veins remain green and become clearly visible. This disease is caused by a lack of iron in the soil, hydrangea and azalea often suffer from it.

It is for these reasons that the leaves turn yellow most often. To restore a flower, it is necessary to provide it with comfortable conditions and eliminate the influence of all dangerous factors. It should be remembered that sometimes the leaves turn yellow and fall off for natural reasons - over time, the leaf plate grows old, and after falling off it is replaced by a new one.

Phlox fungal diseases and methods of protection against them

The most common fungal diseases of phlox, their photos and descriptions, as well as measures for the treatment of plants are contained in this section of the article.

Leaf rust (lat.Cronartium ribicola)

In June, rusty spots appear on the leaves of plants, the size of which is constantly increasing. The leaves gradually die off, and the plant looks depressed and weakened. Most often, varieties with a dark (burgundy, purple) color of buds are affected.

Phlox diseases and their treatment - photo of rust

Affected leaves, and in case of significant damage and completely plants, are weeded out and burned. The soil around is treated with a mixture of one percent Bordeaux liquid, with the addition of copper oxychloride (0.7%) and ferrous sulfate (3%). For prevention, the surrounding plants are also treated.

Septoria or leaf spot (Latin Septoria phlogis Sac)

At the beginning of summer, gray spots may appear on phlox leaves - these are the first signs of septoria. Then they increase in size, turn yellow and a reddish border forms around them. If the area of ​​infection is significant, then the leaf dies off.

Phlox fungal diseases - leaf spot

For treatment, the same means are used as for rust.

Powdery mildew (lat.Erysiphaceae)

At the end of summer, whitish spots can be found on many plants, which gradually increase in size and merge with each other. The leaves dry out and die off. Powdery mildew affects flowers in dense plantings, in conditions of high humidity.

Plants growing in dense planting conditions are more often affected by this disease. An excess of nitrogen in the soil contributes to the infection. For the treatment of phlox, you can use a solution of soda ash (1%), which should be sprayed three times with the plants at intervals of one week.

Perennial phlox, diseases: powdery mildew treatment

A good remedy is foliar feeding with boric acid. Dissolve half a teaspoon of acid in hot water. Then the resulting mixture is diluted with watering to 10 liters of water.

Phoma (Latin Phoma betae)

Phomosis can affect only adult phlox, disease symptoms manifest themselves in yellowing and twisting of the lower leaves. The stem at the root darkens and becomes covered with cracks, becomes brittle and breaks off easily.

Phomosis - a manifestation of phlox disease in pictures

Spraying with Bordeaux liquid for a month at intervals of 10 days helps well. In the fall, affected plants should be cut close to the ground and destroyed.

Bacterial diseases

These diseases are insidious because they are difficult to diagnose. Symptoms are often similar to other conditions. Lead to local or widespread lesions.

They are distributed by insects and they penetrate the plant through micro-holes. Lead to putrefaction, necrosis, tumors, burns.

Black bacterial spot

Cause: Xanthomonas euvesicatoria

It manifests itself in the form of dark growing spots. A yellow strip is visible along the edges of the spots, and as a result the bush dies. It can even occur in seedlings.

  • The seeds are soaked for 10-12 minutes in a solution of potassium permanganate for disinfection, after which they can be planted.
  • The soil for planting must be disinfected by any means.
  • The seedlings are periodically sprayed with Bordeaux liquid.
  • Already infected plants are disposed of.

Lightning-fast bacterial wilting

Called by: Ralstonia solanacearum

Bacteria infect the vessels of the pepper bushes, block nutrient passages and release toxins. It is determined on the cut of the stem in the form of a white liquid.

  • All affected plants are removed from the beds.
  • The seeds are processed in a garlic solution - the crushed two cloves are poured with water and soaked for 30 minutes. After they are dried and sown.
  • They carry out top dressing, observe the rules of crop rotation, maintain temperature and humidity.

Soft bacterial rot

Called: Pectobacterium carotovora, P. atrosepticum, Dickeya chrysanthemi.

It also affects the vessels and the entire bush. The supply of food stops, the plant withers and dies.

Signs are stem hollowness and leaf discoloration. The main reason is high humidity.

  • Seeds and soil are disinfected before planting.
  • Provide regular ventilation and prevent water stagnation during watering.
  • Remove all affected bushes.

Pepper bacterial cancer

Cause: Clavibacter michiganensis

The disease develops at high humidity and high air temperatures, as well as on dense, thinned plantings. Insects or the person himself through tools can become the carrier.

It appears on peppers in the form of dark brown spots with a light color inside. The spots gradually merge into larger ones and are covered with a crust.

  • Sick bushes are treated with copper sulfate or another preparation containing copper.
  • Get rid of already deeply affected plants.
  • If this is a greenhouse, then it should be treated with methyl bromide and it is better to replace all the soil.

Viral diseases and protection technology

Viruses are the smallest particles of a protein substance, invisible in an ordinary microscope, but quite harmful to living plants. They are spread by pests when working on open plant tissues (grafting), water, wind.

External symptoms of the disease

At the beginning of the introduction of the virus, its destructive work is not visible and the plant continues to function as healthy. The manifestation of the disease in terms of external symptoms is in many ways similar to a fungal infection. Spots appear on the leaves, the fruits are deformed. Over time, the differences become more pronounced. Individual spots on the leaves merge into a mosaic pattern of green-yellow colors and shades. Dechlorinated areas of leaf blades become necrotic, affected leaves fall off. Flattening, flattening of shoots, softening of wood is observed. The branches become unusually soft, gutta-percha, and easily break under the load of the harvest. Individual flowers and inflorescences are strongly deformed, taking on ugly shapes. During spring development, at the ends of young shoots, bundles of dwarf shoots with leaves or only leaves of an unusual shape and unusual color are formed. On old branches, bunches of fattening shoots (witch's rings) are formed. The fruits crack, form crusty spots and growths, lose their taste, and also fall off.

The manifestation of mottling on an apple tree

The external manifestations of viral diseases have determined their names. The most common viral diseases of the apple tree: mosaic, star cracking of fruits, paniculate (witch's broom), rosette, proliferation or overgrowth of vegetative and generative organs (ugliness), chlorotic ring spot, wood pitting.

Technological methods of protection against viral diseases

There are no drugs that destroy the virus as a source of infection yet. Therefore, the main control measures are agricultural cultivation techniques.

Agrotechnical measures are the same as those used to combat fungal diseases. Be especially careful when carrying out the following work.

Perform pruning only when the plants are deeply dormant (February).

When pruning, all diseased parts of the plant and the tree as a whole are subject to destruction. Under no circumstances should you use waste for composting.

With a clear manifestation of the most common diseases of rosette and paniculate apple trees, it is necessary to reduce doses when using simple forms of phosphorus and nitrogen fertilizers. Switch to fertilization with complex forms, in which the elements are in the optimal ratio for cultivated crops.

Introduce trace elements, including zinc sulfate, into top dressing, especially with a clear manifestation of rosette.

Use Epin or Zircon phytohormones for spraying, which increase the immunity of plants to viruses. The drugs are effective in preventive measures. They do not stop the developing disease.

Note! The main defense against viral diseases is the destruction of sucking pests, which are the main carriers of viruses.

Bacterial diseases will be discussed in a separate article.

Read more on this topic


A wonderful article on the protection of fruit trees from diseases, I will definitely take note of it. Thank you!

Many thanks. The articles are great, especially for amateurs.

Many thanks! This will help me to cope with diseases of apple trees.

Thanks a lot for the great article! This year, the leaves of the pear growing behind the bathhouse were severely affected by rust. With your article, you reminded me that we urgently need to take action before the onset of winter! I'll start by cleaning the fallen leaves !?

This year, more than ever, this information is relevant. I will take into account all the recommendations. Thank you!

thanks to the author
everything is spelled correctly and most importantly it is intelligible

keep records on diseases of fruit trees. I have a garden for the first year of knowledge, but not enough. want to have a healthy garden. I will fix everything in my power. it hurts to watch when the trees wither

Quote “Apple trees are infected with rust from common juniper. Therefore, juniper plantings should not be located close to the garden. " My juniper has been growing for more than 10 years, the distance from the apple and pear is about 5 meters and there is no rust. I wonder where such recommendations come from - someone wrote without proof and off they'd go.
If this is not the case, then I ask the author to provide a link to the original source.

It affects mainly leaves on an apple tree, and leaves and shoots on a pear, sometimes fruits. Rust develops especially strongly on the pear. The first signs of the disease on the pear are found in early summer (in July, and sometimes even earlier) in the form of pillow-shaped, rounded orange or reddish spots.

Small black dots (spermogonia) appear on the upper side of the spots. On the underside of them, cone-shaped or nipple-shaped outgrowths (etsidia with ecidiospores) are formed, located in groups. Later, these outgrowths open at the apex with cracks. On the shoots in the affected areas, thickening and the formation of the same outgrowths as on the leaves are observed.

On infected apple leaves, rounded reddish spots appear on the upper side, and thin hair-like outgrowths that unfold star-like on the lower side.

The causative agents of the disease are rust fungi on the apple tree - Gymnosporangium juniperinum (L.) Mart. (G. tremelloides Hart.) On a pear - G. dobrozrakovae Mitroch. and G. sabinae (Dick.) Wint. These parasitic fungi are of different households, since in two stages (spermogonia and echidia) they develop on an apple or pear tree, and in the tleithospore stage - on various types of juniper. Urediospores are not formed in fungi.

On apple and pear, rust develops in the summer.

At the end of summer, ecidiospores infect juniper branches and trunks, and pear rust parasitizes tree (tall) and red junipers, and apple rust - only on ordinary juniper. In the bark of infected juniper branches and trunks, perennial rust mycelium first develops for a long time (at least 1.5 years). In the future, on these parts of the plant annually in the spring, telistodes appear in the form of rather large horn-shaped outgrowths, covered with a brownish velvety bloom. In wet weather, these outgrowths swell, become gelatinous and acquire a yellow color. The outgrowths consist of a mass of two-celled telitospores with a long, strongly swelling stem. Germinating teliospores form basidia with basidiospores, which, falling on the leaves of apple and pear, infect them. Germination process of teliospores

Lasts 1.5-2 months. So there is a renewal of rust on fruit trees. Thus, a constant source of apple and pear rust is various types of juniper, which carry the telial stage of the parasite. The development of rust is favored by the warm, humid weather in spring, when telitospores germinate and the apple and pear trees become infested.

Pear rust is one of the causes of premature mass shedding of leaves, which leads to a decrease in fruit yield. In case of damage to shoots of G. Dobrozrakovae, trees develop poorly and are easily damaged by frost. Especially large losses of pear harvest are observed in the region of the southern coast of Crimea, where there are large tracts of various types of juniper. Pear and apple rust is also found in Moldova, Transcaucasia, the North Caucasus and other regions of the southern zone, apple rust is also found to the north.
© Zooengineering Faculty of the Moscow Agricultural Academy

Thanks for the answer. But:
1. Still, this is not a link to the original source, but oh well.
2. The situation with juniper and apple rust mirrors the situation with
Blackcurrant and pine rust in America. There has long been a ban on cultivation
currants and only ten years ago this ban was canceled (apparently, they figured out the causes and consequences).
And we did not have it (the ban) at all!
3. On youtube there is a video with a funny dialogue:
type of journalist comes to the winegrower and admires - it's already the end of August and you have such a clean leaf on your grapes, what are you processing?
The answer is great - but nothing, I just take good care of him!
Like this.
4. Specially went to the garden and examined the pear next to the juniper and I report that I found small spots of rust, but there are so few of them and they, I believe, do not have any effect on the health of the pear: it grows well, blooms and bears fruit.
Take good care of your trees and plant varieties with good vitality and you will be fine!

1. Message rules prohibit proofs. Nobody forbids Google.
2. Doesn't remind. And if they were allowed there, then not everywhere. And not in the USA, but in Canada. And there really is trash, because the main threat to the tui. And the thuja there are simply gorgeous. And in the wild. Red and white cedar are called.
3. Similarly, I have juniper and pears with apple trees. And in the same way, I saw these points. And he noticed that until he cut out the most ailing juniper, the closest apple tree gave very few apples. Although at a glance - it's okay. Moreover, I am struggling with cytosporosis, which, in comparison with these tiny dots, looks like bilateral pneumonia with +40 and a slight runny nose. However, cytosporosis does not at least interfere with the apple harvest.
4. Yes, leaving is first of all, but one should not swear off. The frequency of planting in suburban settlements is very high and the risk of introducing pathogens is constant. By the way - this juniper was just over 10 years old. And apple trees under 20-25.

1. Quote “And if they were allowed there, then not everywhere. And not in the USA, but in Canada. “- I don’t know about Canada, but the situation in the United States is as I wrote. Google "blackcurrant in the USA"
2. By the way, not trash, but trash. And, in general, it is not clear in what sense you used it.

1. Googled more than once. Doesn't apply to the essence.
2. A threat to endemics, and not only, as it represented, and therefore represents a trash.

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