Diseases Of Cacti: Photos, Causes, Treatment

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Diseases Of Cacti: Photos, Causes, Treatment
Diseases Of Cacti: Photos, Causes, Treatment
Video: Diseases Of Cacti: Photos, Causes, Treatment
Video: 5 Most Common Pests on the San Pedro Cactus & Peyote 2023, February
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overfeeding with fertilizers
overfeeding with fertilizers

Overfeeding with fertilizers - the stem cracked.

The causative agents of cactus diseases are bacteria, fungi and viruses. Some diseases can be easily cured, while most cause significant damage to health and lead to the death of plants. Sometimes the symptoms are so imprecise and latent that it is not possible to determine the disease.

Therefore, it is much easier to prevent diseases than to cure the sick, especially when there is not one cactus, but a whole collection. Preventive measures are the strict observance of plant conditions and hygiene.

cactus diseases
cactus diseases

This cactus was frozen, cold air was blowing on it from a slot in the frame.

Unfortunately, in most cases, cactus diseases end sadly. The plant either dies or will be disfigured. Still, most cactusists are tormented by two questions "why?" and "how to treat".

Even after all the repeated explanations that in most cases the cause of illness is a violation of the conditions of detention, people cannot believe that only from once open (in the evening in cold weather) a window can cover an unfortunate cactus with rusty spots and the like. And in fact it is. Even an experienced cactus grower suffers from his fleeting mistakes. Only compliance with all conditions, attention and prevention can prevent the occurrence of diseases.

The fact that a cactus is "sick" is not always immediately apparent. Most often people forget that:

  • opened the window in the evening in cool, windy weather;
  • poured cold water on the cactus;
  • that any wounds, cracks and cuts should be sprinkled with sulfur or crushed coal;
  • to the bright sun, a cactus must be taught gradually, even the most sun-loving;
  • that cacti need a cool and dry wintering.

If a cactus is sick, first of all, you need to remember and analyze what violations in the conditions of detention could have been, whether you did everything correctly.

Sometimes illness, pest infestation or care errors are not immediately apparent. How to understand that a cactus is "unwell", something worries him - just be attentive. It is worth worrying about the cactus in such cases:

External signs Possible reasons
If there is no visible growth of the cactus (only in the spring-summer period) Lack of plant growth in spring or summer is the first sign of some kind of trouble. The reason for this can be absolutely any: a disease or pests, or a mistake in care - first of all, a lack of light, rearranging the cactus to a new place, incorrect transplantation, watering with cold water, etc. After vaccination, as it is stressful. After too long and intense flowering, growth can also slow down or stop due to depletion of the cactus.
If drying or shrinking of the stem occurs If at the same time the stem is firm to the touch, then first of all, the lack of moisture in the soil should be excluded (i.e. watering, the soil is dry), especially if the cactus is in intense light. If the stem, on the contrary, is soft, then the reason is most likely in excess moisture (the soil is damp), at this stage the plant can rarely be saved, you can try an urgent transplant with the removal of all decayed roots.
If there is a discoloration of the stem or leaves This is a fairly common reaction to changing conditions. When rearranging a cactus to a new location. When the light changes (too bright light may cause lightening or reddening of the stem and leaves). When water gets on the stem or leaves (if the plant does not tolerate this). Some cacti genetically have a certain color change with age. In some diseases, the color of the stem and leaves can also change, most often yellowness, browning and mosaic color appear.
If leaves or buds are dropped This may be the first reaction to a stressful situation caused by changes in conditions of detention. Rearranging to a new location, or even because the cactus was turned the other way towards the light source. If lighting, watering, or temperature changes unexpectedly. For example, poured cold water. If the transplant was not carried out on time or correctly. From the discrepancy between micro and macro elements in the soil. It can also happen with diseases or pests.
If shoots die off This occurs most often when the roots are damaged during transplanting or watering with cold water. From a sharp drop in temperature or exposure to a draft. It can also happen with diseases or pests.
If various spots or yellowing appear on the skin This is possible from water getting on the stem or leaves (if the plant does not tolerate this). An untrained cactus can get sunburn from exposure to sunlight. From exposure to cold air, the formation of rusty spots on the stem is possible. With a lack of nutrients in the soil, yellowing is possible, which passes after fertilizing with mineral fertilizers. Yellowing or spots also appear with various diseases and pests.
If wounds or cracks appear on the cactus It may howl caused by mechanical injury. With an excess of organic matter in the soil, the cactus grows vigorously, and the skin cracks and bursts.
If root damage or decay is found The cause of root decay should be sought primarily in waterlogged soil. Especially with a lack of light and low temperatures. Root decay often begins with the fact that lesions, cuts or wounds on the roots were not treated with sulfur (which is needed for drying and disinfection). Insufficient soil moisture at high temperature and light can lead not to decay, but to the death of some of the roots. This happens especially often when the pot overheats in the summer in the sun.
No flowering or short flowering. A common reason is a lack of sunlight, no cold wintering (dormant period), any violation of irrigation and temperature regimes. Some cacti, on the contrary, do not bloom due to too intense or prolonged lighting. Incorrect or late transplantation. Inconsistency in soil pH or composition. Lack of nutrients in the soil or their excess. Moving the cactus to a new place or turning in place. Disease and pest infestation is also the reason for the lack of flowering.

Cactus rot

late blight on cactus
late blight on cactus

Rot is the most common disease, most often caused by disorders in care (excessive watering, cold wet wintering, etc.). Rot is caused by both fungi and bacteria.

Cactus late blight (the causative agent of the fungus Phytophtora cactorum), for example, affects all parts of the plant, especially if there is damage or wounds, but the root collar is most susceptible to disease. Rot is manifested, as we imagine it in the form of decay and the transformation of tissues into a soggy mass.

Among the rot should be noted Helminthosporiosis (the causative agent of the fungus of the genus Pyrenophora) - a disease of crops - the trunks of the cactus bend and dry out, moreover, in just a few days. Another crop disease - Rhizoctonia disease (causative agent of the fungus of the genus Rhizoctonia) or wet rot manifests itself in darkening, blackening of the cactus stem, spreading upward through the vessels. Both diseases can be avoided by disinfecting the land for crops, dressing the seeds, and also avoiding high humidity in the greenhouse.

Fusarium (the causative agent of the fungus of the genus Fusarium) should also be mentioned, which is detected suddenly - the cactus falls, the color of the cactus stem changes (it becomes reddish, brown or purple). If you take the plant out of the pot, its roots break off, they may be completely rotten, depending on the stage. The cactus poison the toxins secreted by the fungi into the vascular system of the plant, which is noticeable on the cut of the stem - a darkened, clearly visible brownish ring.

Decayed cactus treatment

If rot affects the root system, then there are two options. The first - if root decay is only partially (at the very initial stage, usually found by chance) - all affected parts of the roots are removed, and the rest are well sprinkled with coal powder or sulfur, and the cactus is planted in fresh soil with a large proportion of sand. Watering only after three weeks is very careful. The second case, when the roots have rotted completely - you can still save the upper part of the stem by rooting it like a cutting. At the same time, part of the stem is cut off so that only healthy strong tissues remain. If decay of the root collar or stem has begun, then only the top of the cactus can be saved by grafting it onto another healthy cactus.

It happens that stem rot begins at the site of a wound on the skin of a cactus. If the place of decay is not yet large, then you can cut out the decayed tissue with a sharp knife, and carefully sprinkle this place with sulfur. If the wound is small, then a scar will remain, and the plant will recover. But if the damage is significant, the cactus will be disfigured.

If decay has occurred at the very top of the cactus, then it must be cut off until healthy tissue, and the cactus should be used as a rootstock for grafting. You can disinfect all wounds on the body of a cactus with charcoal (you can crush a tablet of activated carbon), gray, as well as brilliant green.

rot on milkweed
rot on milkweed

If you cut off the top of a cactus for rooting from a diseased plant, then prepare a disinfected substrate that must be completely dry. Dry the cactus stalk in the air for a couple of hours, sprinkle the cut with charcoal powder, then put it on the substrate, do not drip it! Do not fix the low crown of a spherical cactus mono - it will not fall, and if the stalk is unstable, fix it on several sides with large pebbles. It is not necessary to cover the entire substrate with gravel on top, a couple of stones is enough.

You can fix it in another way. Stick the stick firmly into the ground, and tie the handle to it with a woolen thread. After that, do not water the cactus for at least 2 weeks. If the summer is hot, i.e. high air temperature, then instead of watering, the cactus trunk is sprayed from a very fine spray bottle, or only the air around the cutting is pollinated and moistened. After 2 weeks, you can slightly moisten the soil in the pot not by watering, but by spraying, so that it remains moist for 2-3 hours, then dries out. An untouched stalk can always be picked up and see if new roots have appeared. If they appear, then the cactus should be left alone (no longer raised), and the spraying of the land should be gradually increased.

If you save a cactus by re-rooting a cutting that has rotted in winter and is in a dormant period, then you will have to place it in growth conditions - the roots will grow only in warmth and with sufficient lighting. Therefore, if you place a cactus in a warm room, assess whether there is enough light for it, if necessary, then put a fluorescent lamp next to it. In some apartments, placement even on the southern windowsill is not enough to provide adequate lighting in winter.

Black rot (causative agent of the fungus Alternaria radicina) - when black (dark brown spots) appear on the trunk of a cactus, in the form of streaks, wet, shiny and disgustingly frightening. The disease can spread very quickly. It is necessary to cut all stains down to healthy tissue. Spray the plant with foundation, Oxyhom or Hom, and dry the cut with sulfur.

dry rot cactus
dry rot cactus

Dry rot (the causative agent of the fungus Phoma rostrupii) or Fomoz - in the direct sense of rot is not observed, it is just that it is customary to call this disease. It is dangerous because when it is discovered, it is usually too late. Outwardly, the cactus turns slightly pale, and begins to dry out imperceptibly. If you cut off the stem, the cactus will be dry inside. Since this disease is transient and methods of dealing with it have not yet been invented, the plant dies. However, you can prevent disease by doing periodic preventive spraying or watering with a systemic fungicide.

Spots - their nature is very diverse, most of them are caused by viruses and bacteria, the appearance of which was facilitated by the conditions of detention. This is primarily the effect of a cold draft, especially in winter, or the defeat of a cactus in conditions of high humidity and cool air. One of the varieties of spotting is rust - the stem is covered with rusty crusts or stains. The cause of the onset of the disease can be sunburn and the ingress of water (especially cold) on the stem and a sharp drop in ambient temperature, etc. The bad news is that once it appears, these rust stains start to appear in other places and spread more and more. Sometimes spraying with a fungicide inhibits the further spread of the disease, and sometimes not, Topaz is used as an anti-rust agent.It is completely useless to try to remove crusts or stains; ugly scars remain on these places.

brown spot
brown spot

It is often possible to notice that having bought, for example, a sick cactus with unidentified spots and placing it at home in a place well-lit by the sun, in a warm place, the spots do not increase, new ones do not appear. This happens often, especially when affected by fungal diseases. Any mushrooms do not like the combination of heat (dry air) and light. Once on a sunny windowsill with moderate watering, the cactus recovers on its own.

But if, in a warm, sunny place, reddish or whitish spots appear and spread along the cactus stalk, sometimes similar to mica, then it’s a tick, which just likes such conditions …

Brown spot, or anthrocnosis (the causative agent of the fungus of the genus Gloeosporium) - in cacti manifests itself in a completely different way than on other plants. On the stem of a cactus, anywhere, both from the sides and on the crown, spots from light to dark brown appear. The spots are dry, depressed, forming a dry crust. The spots are slowly increasing, covering more and more large areas. Fight in the same way - cutting out the affected areas and treating them with fungicides.

bacterial rot
bacterial rot

Brown rot (causative agent of the bacterium Erwinia) - darkening of the cactus stem occurs, as a rule, from the root collar or from any other place (for example, if there was mechanical damage to the cactus skin and the pathogen got into it). In this case, the cactus itself becomes soft to the touch, and gradually changes color to dirty brown. After a while, when a cactus breaks, you can see a slimy, jelly-like mass. As a rule, it is not possible to save the cactus - bacteria and their toxins quickly poison the entire plant.

Yellowing - the cause can be either a lack of nutrients in the soil, or a bacterial or viral disease. Yellowing usually begins at the ends of the shoots and the top of the cactus. First of all, you should eliminate the lack of nutrients and feed the cactus with mineral fertilizer - if the reason for this yellowing will pass. General yellowing can also be caused by a virus, the so-called "jaundice", to fight the disease, there is no way. It can pass quickly, or it can last for months or even years. Moreover, if you take an absolutely healthy-looking stalk from an infected plant, then after a while, it will turn out to be covered with yellowing.

prickly pear virus
prickly pear virus

Viruses in cacti

Viruses are much less common on cacti than people think. In fact, as in other plants, viruses have characteristic features that allow them to be identified, except in those cases when the body of the cactus is densely covered with thorns and it is impossible to clearly see the manifestation of the pattern. And the pattern in viral diseases is always traced.

As a rule, these are concentric rings, various spots that have a certain sequence of manifestation on the stem, for example, the entire trunk of a cactus seems to be speckled - very similar, as if acid was sprayed on it. Some people think that it is a sunburn after spraying, but it turns out that the plant was not sprayed or it did not stand in the sun. The spots are usually light - there is no chlorophyll in the cells in this place. And only cacti infected with a virus that are artificially maintained in culture have a solid, beautiful stem color - red, yellow, white, etc. is a genetically fixed disease.

By the way, it is the grafted cacti that are most often affected by viral diseases.

If you have a suspicion that a cactus has contracted a virus, you can try antiviral drugs sold in a human pharmacy, for example, remantadine (1 tablet in half a liter of water).

fungus on cactus
fungus on cactus

A case from the life of the forum: “As I saw the hymnocalycium, I bought it right away (although I promised to buy the Dutch). Now I don’t know whether to plant it or throw it away, because, in my opinion, there is nothing to re-root there, since they are relatively small. the roots are all wrinkled and some have sores. There were five of them in one pot of different colors. Maybe there is nothing wrong …"

In fact, these cacti did not grow, although the roots, as seen in the photo, are healthy. So, in addition to the fact that in a buried cactus, the lower part of the stem can quite naturally lose color (the process of photosynthesis does not proceed, and it becomes yellowish-brown), in addition, for many species, corking of the lower part is natural due to contact with water and earth and lack of light, this cactus has a fungal infection, as evidenced by an unevenly spreading yellowing spot, as well as brown crusted spots.

The fact that the roots are healthy gives hope that the plant can be cured, wait for new growth, and then re-root the top to get rid of the deformity. For treatment, you can use Hom, Oxyhom, Fundazol or Chinozol. Dilute the fungicide according to the instructions and bathe the cactus in the solution. Then take a new potting mix, sterilize it (for example, keep it in a very hot oven for about 30 minutes, after that it should be absolutely dry, cool).

Then plant a cactus and put it under diffused light. After 3-4 days, depending on the air temperature, pour the fungicide solution. Repeat the stem treatments in a week. If the cactus was in a dormant period, you will have to wake it up - rearrange it to a warmer and brighter place, start drip irrigation. In general, cacti are brought out of hibernation by starting regular spraying from a fine spray. But if a fungal or bacterial infection appears on the cactus, spraying can aggravate the problem. Therefore, it is more correct to start watering a little. Feeding with fertilizers, sprinkling with zircon or epin is also not necessary! Stimulants will not help, and there will be enough nutrients in fresh soil. If there is enough light (you can put additional artificial lighting), treatments have been carried out, such a cactus has a strong chance of recovering.

Cactus pests

How and how to treat cacti

All rot, blotchiness, fungal or bacterial origin are aggravated by high humidity. Those. any spraying (with the exception of fungicide solutions), wet weather outside, etc. is dangerous at the time of illness. If you, for example, are fighting flat or spider mites on a cactus by spraying (with or without insecticides), reduce watering! At the same time, temperature is of secondary importance, but the most severe lesions if the plant was in a cool and high humidity.

It is very difficult to establish a fungal or bacterial disease that struck a cactus; most often, a fungal infection is still found. Bacterial rot is characterized by the formation of soggy mucus, often with an unpleasant odor (but this is already at the last stage, when the plant is almost all affected) and the transience of the disease. Bacteriosis can literally destroy a plant in a day.

Fungal diseases spread at different speeds and depending on the conditions, if cacti are on the balcony and at this time it is rainy weather, then the disease progresses. But even if the spots and other types of lesions (darkening at the root collar) do not increase and do not spread further, it is advisable to treat the cactus with a fungicide.

Fungicides work against fungi and bacteria, they are powerless against viruses. Again, there are some specific features. For example, the systemic fungicide "Maxim" is effective against root rot and decay of the root collar.

Some people use such a drug as Fitosporin to combat and prevent rot, it should be noted that it is very unreliable when the plant is already sick. You may not see any improvement, you should only hope for stronger drugs.

When spots and decay appear on the trunk of a cactus, on the side or on the top of the head, spraying with such preparations as Hom, Oxyhom, Bordeaux mixture, foundationol, topaz is effective. Coloid sulfur helps against certain fungal diseases, such as brown spot. It is not diluted in water as it is written in the instructions for use, but the stains are dusted with a paint brush.

Fungicides for the treatment of cacti

Of the chemical preparations for the treatment of diseases of cacti, Captan is used - an organic fungicide, a substitute for Bordeaux liquid, used in the form of a solution (0.3 - 1%) for irrigation and brushing, or in the form of a powder by dusting (insoluble in water). This drug is effective against many fungal and bacterial diseases, but does not work against powdery mildews. It cannot be used with lime (as it hydrolyzes in the presence of alkalis).

Fundazol is also used to combat pathogens of various diseases. It is used as a solution (0.005 - 0.1%). They are sprayed or rubbed with a brush on stems and roots. The working fluid is not stored.

Sulfur - to combat fungal diseases and mites. Sulfur is an insectofungicide. It is used in the form of an aqueous solution, but sulfur does not dissolve in water, it is only wetted. Therefore, it is more effective to dust the plants with a gray brush.

Chinozol is a preparation for plant protection against diseases caused by phytopathogenic fungi (contact action fungicide-dressing agent). Available in powder form. Quinosol is used against fungal and bacterial rot. If you have not found this drug in a gardening store, you will find it at the pharmacy. For humans, quinosole is marketed as an antimicrobial agent. It is necessary to crush the tablet into powder and dissolve it thoroughly in 1/2 glass of water. Moisten the cactus trunk with this solution and water the soil under the root. Can also be used for soil disinfection and seed dressing. The working fluid is not stored.

Maxim is a preparation for protecting plants from diseases, a disinfectant. Used for seed dressing and soil disinfection (from fusarium, phomosis, wet rot, etc.). The difficulty may be that root rot appears from waterlogging and unnecessary watering, albeit with Maxim's solution, is impossible - you need to let the soil dry thoroughly. Dilute 4 ml of the drug in 50-100 ml, spill the soil with this solution, soak the seeds, and moisten the trunk and leaves of the cactus with a brush or spray. The duration of the drug is about 10 weeks after treatment. The working fluid is not stored.

Topaz - the drug is used to protect against powdery mildew and rust. 1 ampoule is diluted with 5 liters of water. Lasts about 2 weeks. At least 3 treatments are required.

Hom (copper oxychloride) is a means of combating diseases (Late blight, macrosporiosis, brown spot, anthracnose, rust, various bacteriosis and spotting). One of the most effective drugs against diseases of cacti, succulents and other plants. Diluted with 20 g of powder in 5 liters of water. Spraying is repeated as needed up to 5-6 times. The duration of the drug is about 2 weeks. The working solution is not stored.

Fitosporin is a biofungicide for plant protection against fungal and bacterial diseases. In fact, this drug is effective only in the initial stage of the disease. The opinion of many growers: Fitosporin should be used only when there is no other fungicide at hand and for processing the soil after sterilization by heat treatment - i.e. as prevention. To prepare the solution, the paste on the tip of a knife is diluted with 1 teaspoon of water. Then take 4-5 drops in a glass of water and water the ground or spray the plant.

Saves seedlings from diseases by treating seeds and disinfecting the soil before planting cacti (seeds and adult plants). If it is enough to thoroughly steam the soil against pests, warm it up in a microwave oven, in an oven, in steam, then it is not always effective against fungi and bacteria, and freezing is completely useless.

Therefore, it is advisable to spill the steamed soil before sowing seeds, transplanting cacti with a solution of a fungicide, for example, foundazol or quinosol. After that, of course, let it dry.

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