Bacterial burn of fruit crops. New treatments

Have you seen how children die from a nosocomial infection? More precisely, from blood poisoning caused by nosocomial bacteria enterococci and pseudomonads (Pseudomonas aeruginosa).

For forty years as a doctor in a hospital, I have seen this, and now I see how trees in our gardens are dying from "blood poisoning" caused by the same bacteria.

Bacterial blight in US gardens

After all, enterococci, bacteria Erwiniaamylovora are the causative agents of bacterial burns of apple and pear trees in our gardens, when not juice, but “white pus”, but pseudomonas (Pseudomonassyringae - lilac pseudomonas) oozes from cracks in the bark and fruits - contributes to this, cause frostbite in plants, damage to the bark, fruits, roots and leaf spot. It turns out that much has changed in nature due to unreasonable human activity. Man began to suffer from plant diseases, and plants - from human diseases.

The beginning of drying branches

It has been five years since I wrote the first article on treating pear blight with antibiotics. Now an advanced gardener knows what symptoms and how to diagnose this disease in his garden and knows how to treat it.

Who does not know or is afraid of antibiotics can look at thousands of photos and articles on the Internet on this topic. You can watch the new French colorful video of this year, where you can see all the symptoms of a bacterial burn, and you can see how European gardens are sprayed with hundreds of tons of the antibiotic streptomycin, kasugomycin and tetracycline, and copper preparations are even more used.

But around the globe, gardens are still on fire from ervinia, the same with worse results is happening in our southern regions.

Let's slowly talk about why the drugs for this disease do not work.

I will say right away that ervinia is a very capricious and unstable organism in nature. It's easy to kill her. Unlike Pseudomonas, it does not live on the surface of a plant, cannot feed on dead plant remains, but multiplies only in conductive vessels, feeding on plant sap, and then at a temperature above 20 degrees.

Typical bacterial burn on a pear.

Everyone kills her. And frost, and the sun, and dry wind, in the soil, literally in a matter of minutes, it is eaten by other bacteria, fungi and various amoebas. Any drug in contact with live ervinia - an antibiotic, salts of copper, zinc, cobalt, aluminum, iron, silver, chlorine and iodine in a matter of minutes makes it dead, or blocks its reproduction.

Previously, when copper preparations were used in gardens, and not, as now, purely chemical fungicides that kill useful mushrooms, ervinia did not take root on a tree, copper blocked its reproduction, and fungi and bacteria symbiotic with the plant, if ervinia was accidentally introduced onto a tree, they ate it.

But when the whole tree oozes "pus", when there are billions of rapidly dividing ervinia bacteria in all the vessels, then how do you kill them? This is how much poison should be injected into the vessels of the tree?

Exudate discharge typical of a bacterial burn.

If you see the symptoms of the agony of a tree, when large branches dry, when the bark dies in a circle at the root, when not transparent juice, but a white viscous sticky liquid, comes out of the cracks in the bark, then you are too late. It is necessary to be able to treat the disease in the early stages, and even better to engage in prevention.

But for this you need to know who caused the disease in your garden; bacterium, and what, virus, fungus, mycoplasma, or sucking-gnawing insects.

Our topic is the bacterial burn of pear and apple trees.

In a narrow sense, only one agent causes this disease; bacterium ERWINIA AMYLOVORA, moreover, not our local, but imported from the warm regions of the United States, it was from there that it spread throughout the world.

Only she, if she has already taken root in the garden, causes blackening and drying, not of individual twigs or leaves, but “blackening” and death of trees in vast areas, only she has special genes for this, and local ervinia do not have these genes.

In a broad sense, there was a “bacterial burn” in the gardens of Russia even before the arrival of “Ervinia the American. I read studies by scientists 50 years ago who worked in the gardens of the Far East, where there were lesions of branches, bark and fruits similar to the lesions of the “American”, a “white viscous liquid” stood out from the cracks in the bark and fruits, but there were no lesions of trees over a large area . In apple and pear lesions, bacteriological studies have found a bacterium different from ERWINIA AMYLOVORA, although very similar.

There are detailed studies of recent years in Moldova, where a typical bacterial blight caused by American ervinia is rampant. When sowing, a typical “American” is always distinguished, along with it a local weakly pathogenic ervinia and a local very pathogenic Pseudomonassyringae. That is, they meet together in the affected focus.

In addition, in the gardens, where single symptoms of bacterial fire were found, in more and more often foci with fruits with spots of dead tissue with concentric rings of pads of conidial sporulation of the causative agent of fruit rot of the pome fungus Moniliafructigena were found. On the leaves, shoots and fruits of plants, symptoms of damage by the causative agent of apple scab by the fungus Venturiainaequalis were noted in the form of velvety olive-orange spots.

(https://ru.wikipedia.org/w/index.php?title=Pseudomonas&action=edit&redlink=1)

For gardeners, I specifically focus on this. If you see a single focus of plant damage in your garden that looks like a bacterial burn, it is most likely that local bacteria are rampant, and ervinia, if it has penetrated, behaves quietly.

But if in the neighboring large gardens you see massive drying of pears and apple trees with signs of a bacterial burn, remember that soon a foreign bacterium will come to you, show itself in all its glory, and urgent action must be taken.

The first symptoms that will tell you that you have a real fire blight in your garden are as follows.

On your plants, you will find shriveled young shoots bent in the form of a hook, a milky-white exudate that turns brown in the air.

On shoots and pedicels, dried flowers and mummified fruits. But remember, some plant pathogens can also cause exudate. However, when affected by E. amylovora bacteria, in contrast to the causative agent of bacterial cancer Pseudomanassyringae, a cloudy rather than transparent exudate is released. In addition, wood affected by bacterial fruit cancer becomes black, and not reddish in color, as with ervinia.

Be sure to take a look at the neighboring young gardens, it is in young gardens that the plants can be the first to detect typical symptoms of damage by pathogenic bacteria E. amylovora: milky-white exudate turning brown in the air; shoots drying out in the form of a shepherd's staff, as well as mummified fruits.

If the gardeners are not confused yet, I will continue to complicate the topic.

Scientists in last years reconsidered their attitude to fungal fruit diseases.

If you saw branches affected by cytosporosis in your garden, remember cytosporosis is caused by the fungus Cytosporaleucostoma, C. cincta. But first, a bacterium enters the frost holes, into the cracks in the bark, then the fungus joins, and then the fungi develop together with the bacterium Pseudomonassyringaevan Hall. as a single pathological process.

And this is classic cytosporosis

You see the same thing with stone fruit moniliosis and stone fruit bacterial necrosis. First, a bacterium gets on the pistil, then the monilia fungus joins and we see drying pedicels. To treat such fungal diseases with pure fungicides, for example, the well-known preparations of fast and chorus, means not to get an effect. A single process caused jointly by a bacterium and a fungus must be treated with fungicides based on copper or zinc, and also better drugs phytolavin type.

Pseudomonas bacterial cancer

The American female breeds rapidly only at temperatures above 20 degrees and increases its numbers at lightning speed at temperatures of 25 degrees and above. And loves high humidity. The gardener should not miss such weather, look at the forecast and intensify the cultivation of the garden if warm rains are expected.

Pretending to be quiet is the first property of Ervinia.

Accidentally getting into the garden, ervinia behaves quietly, finds a crack in the bark, or on the nose of the bark beetle penetrates into the vessels, slowly accumulates in numbers, does not emit toxins. Its main task is not to die in winter. Although in the first winters it dies by 90%.

The task in the spring will multiply with the beginning of sap flow and seep out. If the gardener missed the first drops of milky white in his garden - that's it, after a couple of years, the death of the garden is guaranteed. These sweet drops are sure to be eaten by flies, bees, wasps, leafhoppers, suckers, psyllids, bugs and other nectar lovers. A week later, from the appearance of these first drops, the mass flowering of the garden will begin. One drop contains a million bacteria. So flies and bees can infect a million pestles.

The first sweet drops appeared next to the dead bark

This is the second top secret ervinia. From a million to make a million million bacteria in just a week. Very fast. And Ervinia is capable of it. Scientists have found that on the pistil of a flower, in sweet slime, in humid conditions, if the temperature is above 20 degrees, ervinium divides every 20 minutes, its numbers increase exponentially. And in a few days, from one drop of pus that leaked from a single crack in the garden, on an area of 1 weave, 1000000000000 Ervinia bacteria grow, evil, hungry, aggressive.

The third secret of ervinia is precisely American, it has a "friendship" gene.

As soon as Ervinia forms a large colony on the pistil or in the vessels of plants, this gene is turned on, and Ervinia stops behaving quietly, begins not only to multiply intensively, but with the help of flagella to quickly move through the vessels, then two more genes responsible for the production of toxins are turned on. One toxin causes tissue necrosis and enhances exudate secretion by the plant, the second blocks the plant's immunity.

These genes contribute to its spread farther and farther through gardens and territories.

Having multiplied in the pistil, it spreads along the pedicels to the receptacle, causing necrosis, drying out of flowers and fruits. And this is a reservoir of bacteria in the form of their capsules with 12 zeros in number. These dry leaves and fruitlets hang and wait for moisture, heat and creeping pests.

And now attention! The fourth feature of ervinia. In warm, humid weather, it is able to multiply in drops of water. Millions of millions of sleeping ervinia capsules turn into billions of billions in a few days of favorable weather. Not a single leafhopper, not a single aphid or codling moth will be left without infection if such a drop falls on it. And all of them will go to the young shoots that grow in the spring to feed on the juice and through the thin tender spring bark they will help the ervinia to penetrate into the vessels. Even ants crawling on young growths will carry ervinia in a warm, humid, rainy summer. A strong wind whips a branch against a branch and causes wounds, as well as hail, a gardener with a pruner at this time - everything contributes to the penetration of huge masses of bacteria into the vessels.

Typical milky white exudate

June-July is always warm and humid. Ervinia begins the second wave of reproduction in the vessels of thin young shoots. Having reached the required number, the bacterium turns on the genes, releases toxins, and in one night, thin young twigs suddenly turn black on thousands of trees at the same time. As if the trees were on fire.

At the same time, flagella begin to work in her, and she moves through the vessels not only with the flow of juices, but also against the movement of juice. The younger the tree, the faster. In hot weather, it can hit the entire one and a half to two meter tree from the tip of the leaves to the root in 3 weeks. At the same time, almost all modern intensive varieties of apple and pear trees do not have immunity to ervinia.

Fifth feature of ervinia. The ability to enter into symbiosis with other bacteria, and subsequently fungi. Ervinia cannot live on the leaf and bark of a tree, but the lilac pseudomona can. And all of them are capable of producing exudate on the surface of the leaf, fruit and young bark. For example, scab spots are always preceded by the appearance on the leaves of clearly visible light chlorotic oily spots, which are a characteristic sign of bacteriosis, and only then scab fungus, monilia fungus, black crayfish fungus, cytospore fungus, multiplying in this mucus, produces enzymes that kill the protective layer of the leaf and bark, then together with the fungus, in collaboration with Pseudomona, ervinia reaches the vessels of the plant. Although more often it enters the vessels on the proboscis of sucking pests.

In some gardens, especially in the north, it is Pseudomona that can cause water crystallization in the bark even with slight frosts and lead to cracks in the bark. For this, Ervinia loves pseudomona very much and is friends with her.

The gardener sees a lightning flash, in a scientific way - scab epiphytoty on leaves, moniliosis on fruits and flowers (drying of inflorescences and fruit twigs), an outbreak of cytosporosis with ring lesions of the bark and fights only with fungi, or sees bacterial burn epiphytoty, and fights ervinia. But in fact, it is always a symbiosis of local fungi and stray bacteria.

The beginning of a bacterial burn on young shoots.

Therefore, modern organic fungicides in pure form inhibiting fungi (including saprophytes and symbionts) enhances bacteria, and antibiotics inhibiting bacteria (including beneficial symbionts) enhance the development of fungi.

So we come to the main principle of the treatment of garden diseases. Everything is like in medicine. Must be killed first harmful bacteria and mushrooms using a complex of combined fungicides and antibiotics, and then populate the garden with beneficial microflora.

Having learned about the keys, about the secrets of ervinium, we will fight it consistently, according to the mind.

These large horticultural enterprises can only apply approved industrial pesticides and antibiotics strictly according to the schemes. And we, in our garden, saving our beloved tree from ervinia, which has flown to us from the collective farm garden, have the moral right to use “any forbidden methods” to fight a foreign terrorist who has entered our territory.

Why did ervinia originate and acquire deadly genes in the southern United States? Because there on large areas industrial gardens. Thousands of single-varietal industrial plantings are grafted onto clone rootstocks. Clonal rootstocks are necessarily viruses and not one, but the whole group of viruses that infect apple and pear trees.

Therefore, my advice to the gardener: if you want ervinia to fly into your garden first - get seedlings from resellers from the south, grafted onto cheap virus-infected clonal rootstocks, graft virus-infected cuttings obtained from unreliable sellers into the crown, and all bacteria will fly to your weakened plants and mushrooms from around, including ervinia and your trees will die first.

I planted my last garden according to the monastic method. Seeds from local healthy antonovka and anise were planted in the ground on permanent place, and planted healthy, virus-free cuttings on them. For 15 years now, the garden has both bacterial and severe fungal diseases my garden is bypassed.

Treatment

American ervinia appeared in the district, last year you had several branches on pears turned black. Where to start?

The key link is two weeks of spring, from sap flow to flowering.

Look on your trees for cracks in the bark where sap is oozing, and for a white viscous exudate oozing. Clean the crack from the rough bark and apply a bandage with an antiseptic. In the age of super-effective antibiotics, I do not recommend using copper preparations and other disinfectants from the past and the century before last for treatment.

Dissolve an ofloxacin tablet in a liter of water, moisten a piece of gauze, apply it to a cleaned wound, cover with a strip of stretch film, and fix this film with anything. Copper sulfate will stop the development of ervinia, but it will not kill it. Ofloxacin is a stronger bactericide for the entire group of gram-negative bacteria, it will penetrate deep into the tissues and kill almost the entire infection.

You can spray the whole tree with ofloxacin no later than 10 days before flowering, two tablets per bucket. You can spray at least copper or zinc preparations, copper oxychloride or cineb. But quality. And forget about the old Bordeaux liquid or blue vitriol, they are very toxic to the plant. Copper oxychloride is ten times more effective and less toxic to wood tissues. It is a pity that it does not penetrate into the tissues of the tree to a great depth, but it will suppress the infection from above, flies and bees will not wear it on their paws.

Buds are swollen, a couple of days left before mass flowering. It is necessary to treat not a tree, but to treat bees and flies with an antibiotic.

The standard is to spray the tree with an antibiotic from now on. Streptomycin is used worldwide in combination with tetracycline. Or a more modern kasugamycin. We have no worse phytolavins. Tetracycline supplementation is needed as it 100% prevents the development of Ervinia resistance to streptomycin.

Tetracycline and streptomycin are used in industrial gardens because they are very cheap. It is easy to establish their production. But modern medical antibiotics are certainly more effective. Streptomycin is destroyed in a few days and does not penetrate well into the tissues of the tree. Does not enter vessels.

I would suggest using ampicillin. It will penetrate deeply into the tissue of the plant, it is absolutely non-toxic for bees, it lasts longer on a tree, a bottle of 1 gram per bucket costs 10 r.

But there is little secret, I read it in the monographs of scientists who treated bacterioses of trees back in the 60s. They sprayed the trees with penicillin antibiotics a few days before flowering. They added a glass of sugar and a spoonful of honey to the bucket instead of a synthetic adhesive. With an excess of such feeding, bees and flies completely refused the “pus” secreted by ervinia, and ate only sugar-honey syrup with penicillin. Even accidental ervinia bacteria, falling on a bee stained with an antibiotic, quickly died. The transfer of ervinia to the pistil of blossoming flowers did not occur. Ervinia during the flowering period could not increase its population millions of times, the epidemic process was interrupted at the very beginning.

Try to do this a couple of times, before flowering and at the very beginning of flowering, you will succeed. Then, with an interval of 3-5 days, spray the flowering and flowering garden twice with phytolavin (streptomycin), preferably at the end of flowering, do not forget to add a drug against fungi, best mixed with phytolavin. They match well. And after a couple of weeks, during the period of regrowth of the shoots, you can apply a combined contact-systemic fungicide containing chlorine copper oxide, even better zineb. The drug of choice may be - Ridomil Gold or Acrobat.

Mid-summer, tender shoots grow, no matter how we fight Ervinia during the flowering period, individual pistils, invisible to our eyes, could be infected. Therefore, as soon as the warm rainy season begins, it is necessary to spray the garden with preparations that reliably kill ervinia. Preparations of copper or iodine or silver, of course, will block for ervinia small cracks on the bark, but it is more reliable to use systemic antibiotics.

Phytolovin by 80 percent will reduce the defeat of young branches at this time. But if you treat the garden with ampicillin and ofloxacin, either together or with a break of a week, they will be perfectly absorbed through the leaves and can kill ervinia even from the vessels of the plant.

Two or three such treatments for prevention and for the treatment of mild lesions are more than enough. If the plant became seriously ill, you noticed the disease when large branches began to dry out and white exudate began to ooze from the wounds on the bark, you can save the plant only with antibiotic droppers. But this is a separate issue. Resuscitation of diseased trees.

A gardener from Dnepropetrovsk sent me a series of photographs; on my advice, he treated young pears that showed signs of a tank. burn. During the season, once every 2 weeks, he simply sprayed the trees with streptomycin, alternating with the drug Skor. The effect was obtained after the first spraying. The disease stopped, new shoots with healthy leaves began to grow, and in the fall the trees looked completely healthy. Neighbors' diseased trees died even though they sprayed them blue vitriol.

Eugene from Dnepropetrovsk sent this photo in May.

And this is one of these days.

Autumn. Ervinia ceases to multiply, turns into capsules. At this point, antibiotics will not reach her. Ervinia hopes that the gardener will make mistakes, the plant will leave in the winter weakened by fungi and viruses, overfed with nitrogen, and in an unfavorable winter with frosts alternating with thaws, frost cracks and cracks will appear on the bark. This is the best that Ervinia can dream of for its reproduction.

To help her and the pseudomona, she accumulates in the forks of trees extending under acute angle, and releases a toxin that reduces the frost resistance of the tree. Therefore, the pre-winter treatment of the tree with preparations of copper or zinc will not reach ervinium, and will destroy pseudomonas.

My friend, a farmer and businessman, Dmitry Madzhar, sent me excellent preparations Bionur and Thiofer containing thiobacils for testing. And what kind of animals are these?

I suggest trying out thiobacils in your gardens for both spring frost protection and winter stress protection.

Now we are gradually moving on to other organic methods of combating plant bacterioses.

I always after using fungicides or antibiotics in my garden, as soon as their action ends, after 3-5 days I spray the garden with high-quality ACC. I have dozens of articles on this topic. Millions of fungi and bacteria symbiotic for the plant, propagated in the ACC, will protect the leaves and bark from the invasion of pathogenic bacteria and fungi.

But there are other drugs for the prevention of bacteriosis. I will name affordable and effective.

Based on different strains of hay bacillus, there are: Fitosporin (Bacillussubtilis, strain 26 D), Alirin (Bacillussubtilis, strain B-10 VIZR), Baktofit (Bacillussubtilis, strain IPM 215), Gamair (Bacillussubtilis, strain M-22 VIZR).

On the basis of bacteria of the genus Pseudomonas, a number of drugs are used: Pseudomonas (Pseudomonasaureofaciens, strain BS 1393), Elena (Pseudomonasaureofaciens, strain IB51), Planriz (Pseudomonasfluorescens, strain AP-33), Binoram (Pseudomonasfluorescens, strains 7G, 7G2K, 17-2).

Based on the bacteria Streptomyceslavendulae, strain 696, the antibiotic drug phytobacteriomycin (Fitolavin) is produced.

Poly-beta-hydroxybutyric acid, is a biopolymer from soil bacteria Bacillus megaterium and Pseudomonasaureofaciens. It contains the Albit preparation, it enhances the immunity of plants, their natural ability to resist diseases.

Recently, highly effective microbiological preparations of a new generation, STIMIX FITOSTIM and FITOSTIM, have appeared on the market.

You can read about them on the Internet in the articles of Alexander Kharchenko. They contain more than 70 types of beneficial bacteria, of those that were mentioned in the preparations a little higher, they are made very high quality, and sometimes they protect against bacteriosis better than any antibiotics, while not violating the ecology of the garden, as well as ACH and together with ACH improve and quickly restore the biodiversity of biota in the soil and biota on plant leaves.

Therefore, in my new garden, I completely abandoned the digging of the soil, the destruction of weeds, and the intensive use of mineral fertilizers. I do not rely on green manure, but every year I make a lot of organic matter, mostly coarse. But I remember that the beveled foliage and fresh manure in trunk circle in a young garden, it is a breeding ground for pathogenic bacteria and fungi, primarily Fusarium and Pseudomonas. Therefore, such organics must be watered with ACC or Stimex. If you were unable to purchase either one or the other, then you can always purchase high-quality vermicoffee, that is, an extract from good compost obtained with the help of worms. It is produced and distributed by my friend Gennady Mulyarchik. It works no worse than AKCh, as it contains a rich set of bacteria and fungi useful for plants.

In an old garden, when natural biodiversity has formed in the soil, everything can be applied - sawdust and wood chips, garbage with foliage from old parks, and any manure. Biota processes everything with lightning speed, destroys harmful Pseudomonas and Fusarium fungi, if there is moisture.

But with organic top dressing, do not forget to monitor the growth of young branches in July so that the plant does not fatten, there is no nitrogen overfeeding.

And then ervinia will come to your garden last, or maybe never come. A healthy garden is filled with healthy microbiota.

President of the Association of Gardeners of Russia (APPYAPM), Chairman of the Association of Nursery Gardeners (ASP-RUS), Doctor of Agricultural Sciences

THEM. Zueva, Ph.D. s.-x. Sciences

N.P. Semina, Ph.D. s.-x. Sciences

Bacterial burn of fruit crops

In recent years, outbreaks of fire blight (“bacteriosis”) have been observed in gardens. There is evidence that the main risk areas are the Volga region, the Southern Federal District, the Central Federal District, North Caucasus and others. This publication was specially prepared to teach gardeners to recognize this disease and fight it, thereby preventing the massive nature of its development.

Active bacteriosis infection on annual apple growths

Bacterial blight of fruit crops (Erwinia amylovora) is the most dangerous disease of apple and pear trees. The pathogen infects more than 100 plant species. The disease is common in the USA, Canada, Mexico, Chile, Colombia, New Zealand, China, Japan, Saudi Arabia, Egypt, Turkey, Armenia and most European countries (Smetnik, 2003). AT recent times there was a danger of its spread in Russia. Due to its high harmfulness, the causative agent of fire blight belongs to quarantine objects. Under favorable conditions, it may take only a few weeks for the disease to develop from infection to the complete death of a tree (Belyaev, 1998). The infection affects all parts of plants. Flowers, annual shoots and young ovaries of fruit crops are most susceptible to infection.

Pear fruit rot caused by Erwinia amylovora

The bacteria E. amylovora are mobile gram-negative rods with large quantity flagella on the surface. They do not form spores or capsules (Belyaev, 1998). In the spring, with the beginning of sap flow, bacteria become active and begin to multiply. This is facilitated by high humidity and temperatures above 18-20°C. As a result of the multiplication of bacteria, an exudate appears, which is released to the surface in the form of small drops or an imperceptible thin film and is the source of the primary infection of flowers, leaves and annual shoots.

The development cycle of a bacterial burn.

If a strong reproduction of bacteria in the spring coincides with the flowering of an apple or pear tree, there is a danger of an epiphytoty of the disease. Large epiphytic populations of the pathogen usually develop on the stigmas of pistils. Ants, bees, wasps, bumblebees, flies, and aphids are carriers of the inoculum (Braun and Hildebrand, 2006). Active infection can develop during rainfall, heavy dew, washing bacteria from the stigma. Bacteria penetrate into the openings of nectaries, where they find a favorable environment for their development. Most often, the manifestation of symptoms of the disease is less than the number of colonized flowers (Buban, Orosz-Kovaes, 2003). Over long distances, the infection is carried by birds (mainly starlings and thrushes) or with planting and grafting material (Smetnik, 2003).

Erwinia amylovora infection on unripe pear fruit

Bacteria enter leaves, green fruits, shoots and skeletal parts of plants mainly through wounds, cracks or natural openings, such as stomata. After 36-48 hours after injury, bacteria can rarely infect plants, and after 72 hours they practically cannot. On the sunlight in drops of exudate, the bacterium can remain viable for up to 22 hours, and without light - more than 2 months. Ripe fruits are not susceptible to infection. The development of a bacterial burn is influenced by: the concentration of the inoculum, the relative humidity of the air, and the temperature. The latent period noticeably increases with a decrease in temperature from 29°C to 16°C (Norelli and Beer, 1984). The pathogenicity of E. amylovora is driven by changes in host physiology. Pruning of plants, application of mineral fertilizers (especially nitrogen and potassium) and growth regulators contribute to slowing down or accelerating the development of the disease (Blachinsky et al., 2005).

The first signs of infection can be detected shortly after flowering plants. Affected flowers become watery in appearance, then darken and wither. Dried apple flowers become dark brown, pear flowers almost black, and both do not fall off during the season. On unripe apples and pears, oily reddish-brown or silver-brown spots appear, a short time covering the entire surface of the fetus, sometimes with small drops of exudate. Over time, the fruits mummify.

Bacteriosis of pear ovaries

On the leaves of the apple tree, small reddish (dark brown in pear) necroses first appear between the veins, which spread to the periphery, increasing in size. Young green shoots wither, their tops are bent in the form of a staff. First, the infected tissue becomes shiny and covered with an oily substance, then necrotic and shrinks. In humid weather, there is copious excretion bacterial exudate milky white, then yellowish amber. On a tree, the infection spreads from top to bottom, i.e. from annual growths to older branches and trunk. The bark of the skeletal branches at the site of infection becomes swollen, wet, under pressure, the sap seeps through the cracks. The defeat of lignified tissues at the end of the growing season can be manifested by barely noticeable necrosis. With extensive damage to the branches or trunk, parts of the crown die off above the site of infection. A severely affected tree looks like it has been scorched by fire. With the onset of hot days, the disease becomes less active, and a noticeable border is observed between healthy and affected tissue, which is manifested by a characteristic crack in the cortex. Such a dormant focus remains for the winter, and in the spring the mass spread of the disease again occurs. There is also evidence of a latent infection of the burn pathogen in woody tissues, which develops without noticeable external manifestations (Smetnik, 2003).

Initial symptoms of leaf damage by Erwinia amylovora bacteria

A distinctive feature of the development of E. amylovora is the release of bacterial exudate (Belyaev, 1998), but it occurs under conditions high humidity air, and under unfavorable conditions for the pathogen, exudate may be absent, which can lead to an incorrect definition of the disease. Thus, the symptoms of a burn may resemble winter abiotic damage, the development of various bark and wood mycoses, damage by some insects, etc. Most often, the similarity is observed when the bacterial necrosis of the cortex (Pseudomonas syringae) is affected. But, unlike E. amylovora, the fluorescent bacteria P. syringae infect trees without exudate and with more low temperatures air (about 10-15°C). The causative agent of necrosis produces a diffusible pigment on King's medium, which gives green fluorescence. Infection of apple flowers by the fungus Monilia fructigena and the spread of infection to the shoots can also look like the development of E. amylovora. Such fungal pathogens as Cytospora spp., Nectria galligena, Sphaeropsis malorum and some others sometimes recolonize lesions infected with bacterial burn, which greatly complicates the diagnosis of diseases. For exact definition causative agents are used: tests on tobacco (hypersensitivity reaction according to Klemety, 1976), on unripe pears (White, 1961), serological analysis, immunofluorescent method, dot-Elisa and DNA hybridization method. In 1992, EOCR published diagnostic protocols for horticultural scorch.

Withering of annual growths under the action of a bacterial burn.

Modern varieties of apple and pear have different susceptibility to fire blight. There are no immune varieties. According to various literary sources and our observations, apple varieties are very susceptible: Idared, Jonathan, Gala, Geneva, Aport, Spartan, Champion, Skoroplodnoe, Low-growing, March, Vityaz. Medium and slightly susceptible varieties: Jonagold, Empire, Bosco, Golden Delicious, Red Delicious, Cortland, Paulared, Pinova, Zhigulevskoe, Krasivoe, Cherry, Mechta, Melba. To a large extent, the susceptibility of plants depends on the rootstock of the apple tree. Most of the dwarf rootstocks (M9, M26, B9, P2, P22, P29) are very susceptible to the blight pathogen. Less sensitive: MM106, M7, MM111, 62-396, 54-118 (Van der Zwet, Bell, Blake, 1984).

The defeat of the terminal shoots bacteriosis

Pear trees are more affected than apple trees. Among foreign varieties, the most susceptible are: General Leclerc, Durandu, Triumph Pakgam, Santa Maria, Williams pear, etc. (Smetnik, 2003). Relatively stable variety Conference, which occupies the largest area in the countries of Western Europe.

The defeat of the stem pear

Of the existing control measures, none of them fully guarantees the recovery of an infected plantation, therefore, the main elements for preventing the spread of fruit blight are the use of healthy planting material and the timely detection of foci of infection. Import to Russia of planting material from countries with foci of bacterial fire is allowed only if there is a quarantine certificate. In apple and pear orchards, it is necessary to conduct regular inspections of plants, starting from the end of flowering until harvest.

Promotion of Erwinia amylovora infection from inflorescence to trunk

In world practice, the following measures are used to combat bacterial burns:

Uprooting and burning of plants in plantations where the drying of trees reaches 30% or more. With a weak infection of trees, it is allowed to remove individual affected branches of the crown with the capture of healthy tissue 20-40 cm. below the visible border of the lesion. An obligatory element is disinfection of the cutting tool with 10% copper sulfate solution, 70% methyl alcohol or 10% Na hypochlorite solution, disinfection of sections with 1% copper sulfate solution and coating them with garden pitch or emulsion paint (Belyaev, 1998).
Removal of wild fodder plants, especially hawthorn and cotoneaster, growing at a distance closer than 500m from the garden.
Control of vectors: aphids, suckers and other insects.
Refusal to apply high doses of nitrogen fertilizers, increase of nonspecific resistance of plants to unfavorable environmental factors (Blachinsky et al., 2005).
Refusal of summer green operations in infected stands.
Most effective method protection of plants in the foci of the spread of infection is the use of antibiotics during the flowering period. The most popular is streptomycin, in Europe it is replaced by plantomycin, kasugamycin and other drugs. In Russia, the use of antibiotics for agricultural purposes is prohibited.
The chemical method is used to reduce the development of infection and prevent new infections. Modern fungicides, except for copper-containing ones, do not affect the blight pathogen (Paulin and Lachaud, 1984; Smetnik, 2003). With the threat of the spread of bacteriosis in the plantations, treatment with copper-containing preparations is carried out starting from the “green cone” phenophase until the end of the active growth of annual shoots with an interval of 10-14 days.
In addition to the above preparations against bacterial burns, soda hypochloride, oxolinic acid, aluminum fosethyl, Regalis, bacterial preparations (antagonists of Rahnella aquatilis Ra 39 and Pseudomonas spp. R1) are used in various countries (Laux, Zeller, 2002; Kbitman et al., 2005).

Cracking of the affected bark caused by bacteriosis of the apple tree

Specific control measures are determined by the State Quarantine Inspectorate, contacting which is mandatory when identifying characteristic symptoms of the development of a bacterial burn.

Literature

Belyaev, S.V. American bacterial blight of pome fruit crops. /S.V. Belyaev // Horticulture and viticulture. – 1998 - No. 4. – p. 14
Smetnik, A.I. Bacterial fruit blight. / A.I. Smetnik //Protection and quarantine of plants. - 2003. - No. 10. – pp. 38-39
Blachinsky, D. Effects of growth regulators and pruning on the susceptibility of pear trees to Erwinia amylovora. /D. Blachinsky, D. Shitenberg, D. Weinthal, Sh. Manulis, E. Zamski // Phytoparasitica - 2005. - V.33, N 3.- P.294-295
Brown, P.C. Epidemiology of fire blight of floricane fruiting red raspberry caused by Erwinia amylovora. /P.C. Brown, P.D. Hildebrand // Can. J. Plant Pathol. - 2006. - v.28, N1. – P. 95-99
Buban, T. The nectary as primary site of infection by Erwinia amylovora (Burr.) Winslow et al: a mini review. /T. Burban, Zs. A. Orosz-Kovaes // Plant Syst. end Evol. - 2003. - 238.N1-4. – P. 183-194
Klietman, F. Erwinia amylovora populations resistant to oxolinic acid in Israel: Prevalence, persistence and fitness. / F Klietman, D. Blachinsky, D Oppenheim, M Zilberataine, O. Drar, S. Manulis // Plant Pathol. - 2005. - 54.N2. – P.108-115
Laux, P. Studies on the biological control of fire blight in Egypt (8 Symposium “New Aspects of Resistance Research on Cultivated Plants Bacterial Diseases”. Aschersleben, Nov. 15-16. – 2001). / P. Laux, W. Zeller // Bundesanst Züchtungsforsch Kulturpflanz. - 2002. - 8.N3. – C.46-48
Norelli J.L. Factor affecting the development of fire blight blossom insections. / J.L. Norelli, S.V. Beer //Acta Horticultural. - 1984. - 151:37-39
Paulin, J.P. Comparison of the efficiency of some chemicals in preventing fire blight blossom infections. /J.P. Paulin, G. Lachaud // Acta Horticultural. - 1984. - 151:209-214

Cultivated plants, like humans, are susceptible to attack by various pathogenic microorganisms. Fungi, bacteria, viruses multiply rapidly, and the products of their vital activity cause irreparable harm to the health of the plant organism. One of the most insidious diseases affecting gardens is pear blight. In fact, other members of the Rose family also suffer from it, but pears have a genetic predisposition to infection. What caused the disease, how to recognize it in time and not confuse it with other diseases, what measures to take to protect the garden, how to treat infected trees, you will learn from the materials of the article.

The causative agent of the disease

Outbreaks of bacterial fire of fruit crops on the territory of Russia until 2009 were not recorded. The imported phytopathogen Erwinia amylovora was previously found only in America, Australia, and Canada. Ervinia is a stick that can move in environment with the help of flagella. In these countries, outbreaks of pear blight have been observed since the end of the 18th century.

The sale of infected genetic material helped the bacteria to spread to all corners of the world. And now Ervinia is already proudly marching through our country, destroying industrial and amateur gardens. So far, the disease has not received such a large-scale spread. The All-Russian Center for Plant Quarantine recognized it as limited distribution.

The gram-negative microorganism leaves behind scorched plantations, for which it is popularly called the fireweed.

The mechanism of the development of the disease

It is not typical for Ervinia to form spores or capsules; it reproduces by division. Under favorable conditions, the colony grows rapidly.

The disease is divided into the following phases:

During the primary infection of a pear, the pathogen penetrates through the bark into the cambium, gradually increasing in numbers. During the first wintering, up to 90% of the colony dies out.
With the advent of spring, the remaining bacteria in the process of sap flow get outside. The released exudate has a milky hue, in contrast to the transparent one that has a bacterial cancer. These diseases are often confused, but cancer is caused by a fungus, and a burn is caused by a bacterium.
The exudate contains many rods. They are carried by various insects and fall on the pistils of the culture, where secondary infection occurs.
In just a week, the number of ervinia grows exponentially. On the onset favorable conditions phytopathogen divides every 20 minutes. Through the pistil, the bacterium enters the conducting system of the plant, where it actively moves with the help of flagella.
Having penetrated into the vessels, ervinia activates genes for the production of toxins. Toxic substances suppress the immunity of the pear and contribute to the death of tissues. Due to necrosis, the process of excretion of exudate is enhanced.
Through the pistil, the bacterium reaches the receptacle and ovaries, contributing to their death. This symptom resembles a monilial burn, but the diseases have different pathogens and conditions for development.
Necrotic tissues are tightly held on the branches and "wait" for rain to spread over long distances together with water drops. Each potential "visitor" of the garden - a pollinator, a bird, a pest - becomes a carrier of ervinia. Bacteria enter through cracks in the cortex new organism and the cycle repeats.

The optimal conditions for the development of the bacillus are considered to be high humidity and a temperature background of over 20⁰C. Moniliosis develops at low temperatures in combination with high humidity.

The pathogenic microorganism most often affects young seedlings, because their thin bark facilitates easy penetration into the conducting system. The pear variety plays a significant role in this, because some cultivars have a much higher genetic predisposition. Excessive nitrogen fertilization can also provoke the disease. Nitrogen provokes the rapid growth of plants, enhances metabolism. Because of this, sap flow is accelerated, ervinia spreads faster inside the vessels. Warm torrential rain, combined with strong winds, contributes to the rapid spread of bacteria over long distances.

alarm bells

The gardener should vigilantly monitor the condition of young pear seedlings. The course of the disease is accompanied by the following symptoms:

upon awakening of the kidneys, inhibition of the opening process is noted, followed by blackening. Damaged buds are not in a hurry to fall off, until the end of the season they will be firmly held on the branches;
with a lesion during the budding period, the corollas wither. They dry up and turn black, but also remain on the tree;
the subsequent advancement of the phytopathogen is accompanied by blackening of the deciduous mass with twisting of the leaf blades, which is clearly seen in the photo. The seedling looks charred, as if a wave of fire has scorched its tops, hence the name of the disease;
the appearance of brownish-red stains on the bark with oozing viscous milky exudate is a sure sign of a bacterial burn;
at the last stage of infection, necrotic areas appear on the trunk and skeletal branches, accompanied by detachment of dead tissue. In this case, the tree can no longer be cured, it has completely died.

Noticing one of the listed signs, tissue samples should be taken to a microbiological laboratory to confirm the diagnosis. Indeed, often anxiety is in vain, and under the guise of an imported disease, a monilial burn is hidden. The tactics of treatment in this case changes dramatically.

Ways to get rid of a plant disease

At the initial stage, the disease is suppressed by various means. But first you need to carry out a complete cleaning of the seedling. With a treated pruner, remove all diseased shoots, capturing up to 20 cm of healthy tissue. Pity is inappropriate here!

If there are cracks on the pear bark with oozing exudate, wipe the liquid with a rag soaked in a solution of copper sulfate. Then clean the wound with a garden knife, removing all damaged areas down to healthy tissue. Prepare a gauze pad and antibiotic solution. In a two-liter jar, dissolve 2 tablets of the drug. Moisten the cloth and apply to the wound surface, fix with cling film.

All plant residues must be destroyed immediately. Never bury cut branches. You can't put them in a compost bin. It is best to burn the source of infection.

Treatment with chemicals

Treatment of the initial stage of a bacterial pear burn is carried out by five times treatment with copper-containing preparations.

Bordeaux liquid has long been used by gardeners as a fungicide. When preparing the solution, observe the proportions, since an excess of copper sulfate leads to a chemical burn. Purchase copper-containing preparations at the garden center - Skor, Oksikhom, copper oxychloride. They inhibit the development of ervinia from the outside, disinfecting the surface. In this case, insects will no longer spread the bacteria.

After a total cleaning, spray the pear tree with the prepared solution. The procedure is carried out in five stages:

upon awakening of the kidneys;
during the blooming of the deciduous mass;
at the end of flowering;
15 days after the last spraying;
at the end of the harvest.

Medicines (antibiotics) from a pharmacy

Human antimicrobial drugs have shown excellent results in the treatment of fire blight. The action is based on the destruction of the DNA chain of the phytopathogen. Processing is carried out every 20 days from the moment the leaves appear. It is not advisable to use the same antibiotic more than one season, because the bacteria gradually acquire immunity to it.

Remember, if precipitation has passed between sprayings, you need to additionally process the pear. The same goes for extremely hot weather. The event is held strictly in the absence of the sun.

To treat a tree, gardeners use the following medicines:

streptomycin. It is diluted at the rate of 500 mg (1 ampoule) per 5 liters of water;
tetracycline drugs. Enough two tablets per three-liter jar of water;
ofloxacin. Two tablets per bucket of water;
gentamicin. Ampoule 2 mg dissolves in a liter of water.

Between treatments, use biostimulants that will support the plant's immunity. The following video will tell you more about the treatment of a bacterial burn with antibiotics.

little trick

To protect the garden from spreading ervinia, before the buds open, spray the trees with an antibiotic solution, to which add 200 g of sugar and a little honey. This will distract insects from the exudate and lead to the death of bacteria.

Uproot plants that provoke the disease - hawthorn, wild stone fruits.

Cardinal measures of struggle

An infected pear can destroy an entire garden, so some gardeners prefer to use uprooting immediately. The excavated specimen is burned.

New means of struggle

Among the new preparations for bacterial burn, gardeners preferred:

Previctory. Blocks the ability of microorganisms to reproduce, destroys fungi, improves immunity;
Bionuru, Thiofer. Used for the prevention of frostbites;
Stimexam, Gamairu. Microbiological preparations containing beneficial flora.

Follow the instructions for use of the described products.

In the treatment of illness folk methods do not apply. This is due to the recent emergence of the disease and the increased resistance of the pathogen. On the early dates gardeners use Farmayod, which is diluted 10 ml per bucket of water. Spray the tree during budding and fruit filling.

Preventive measures

In order not to have to treat a terrible disease, follow the safety measures. Carefully inspect the seedling before buying. Purchase planting material only in nursery. Use for planting varieties of pears that are resistant to bacterial burns - Bere Gardi, Lukashovka, Favoritka. Remove plant debris and weeds promptly. Be sure to carry out preventive spring and autumn processing. Use disinfected garden tools. Carefully inspect landings.

It is difficult to treat a bacterial burn - you will have to make every effort, try more than one drug. But watching your favorite pear tree heal will bring you incredible pleasure.

They didn't know how to treat a tree and what hit it. But now we will deal with this problem in more detail.

Description of the disease

Bacterial burn - disease fruit trees, which is widely distributed in Australia, USA, Canada, Japan and some European countries.

In recent years, this disease has appeared on western Ukraine. Bacterial burn in most cases affects plants of the Rosaceae family. Boles, shoots, leaves, roots, fruits are affected. This disease affects flowers in early spring. After that, they wither, and then dry up and remain on the tree until late autumn. From the affected flowers, the bacteria pass to the shoots and leaves. Thus, the whole is affected.

This disease is caused by bacteria from the genus Ervinium. The homeland of this disease is considered to be North America, from where the bacteria spread throughout the world.
The largest losses of fruit trees that were affected by fire blight were recorded in Australia and New Zealand.

Soon, the bacteria spread to Japan, where they began to actively infect pear trees. Japanese agronomists for a long time could not understand the cause of the disease of fruit trees, and only a few years later a certain scientist identified the cause of the disease - gram-negative aerobe.

The first signs of illness

Most often, this disease is detected during the flowering period of the pear. The flowers on the tree first fade, and then suddenly dry and turn black, while they do not fall off the branches for a long time.
When the flowers are already infected, bacteria begin to multiply throughout the tree, affecting leaves, branches, bark, roots, etc. After this, the bark may become watery and take on a greenish tint.

Leaves that are infected dry out and turn dark brown. And the most interesting thing is that they remain on the branches throughout.

Did you know? For the first time, a bacterial burn was discovered in the United States at the end of the 18th century.

As a rule, at first the leaves turn black only on one shoot (while they are twisted into a tube). Then the entire shoot is affected, which dries up and dies very quickly. Soon the bacteria begin to infect other parts as well. In some cases, this leads to the complete death of a young tree.
Bacterial pear blight can be accurately determined in the laboratory. To do this, you need a dried shoot or a couple of dried leaves.

Shoots are given to quarantine services, which confirm or deny the presence of bacteria of the genus Ervinium. For this, they are used such methods: Clement reaction, Gram stain or molecular methods.

Causes of a bacterial burn

The main cause of the appearance of a bacterial burn is considered to be wasps. These during the growing season feed on exudate (mucous fluid).

This liquid is secreted by the pear tree in places that are affected by bacteria. As a result, the wasps spread millions of bacterial bacilli to other trees. This is especially dangerous when a large number of young seedlings are growing in the garden.

Also, this disease can spread in the root zone (in cases where the trees in the garden grow close to each other). Gardeners often think that common root rot affects the roots, so they ignore a dangerous disease.
Sometimes on the affected leaves and pear flowers, droplets of amber or milky color can be observed. These droplets contain several million bacilli, which are spread to other trees by flies and other insects.

The cause of infection with a bacterial burn can be strong wind, rain or fog. Bad weather conditions can spread droplets filled with bacteria to the flowers and leaves of other plants.

Treatment of the disease

If you notice signs of a bacterial burn on your pear, then, first of all, you need to remove the blackened shoots and leaves, and then burn them. The affected branches are burned in order to completely destroy all bacteria on it (they die at temperatures above 43.7º C).

The affected area must be disinfected with copper chloride or. If the seedling completely died from a bacterial burn, then new trees should not be planted in its place for the next two years.

Bacterial pear blight can be treated with antibiotics. Growers of the countries Western Europe antibiotics have been used for a long time, as they do not see a big effect from copper-based drugs. Among antibiotics, terramycin and streptomycin are very popular.

Do not be afraid to use these drugs. For example, streptomycin has not been used by doctors for a long time. Human pathological bacteria have long developed immunity to this drug, therefore, it is harmless to the body.

But for bacteria that infect trees, in particular for, this antibiotic is a deadly weapon. Apply it like this: one ampoule per 5 liters of water; this solution is enough to spray ten pear seedlings.
But do not use streptomycin for more than 2 years in a row. After some time, bacteria can develop immunity to it, and they will no longer die from the action of the antibiotic. In this case, tetracycline can be used. It should be diluted in the same way as streptomycin.

Did you know? The bacteria that cause pear burns begin to actively develop at temperatures above 18º C.

Bacterial pear burn requires proper treatment on the most initial stages. Otherwise, the disease can affect neighboring trees.

Prevention

If a bacterial pear burn is detected in a timely manner, then the tree can be cured without critical consequences. Prevention in this case plays a very important role.

Good selection of seedlings

When choosing pear seedlings, you need to pay attention to branches, leaves, trunks and roots. The trunks should be even, and the twigs healthy (no spots, wounds, nodules and juice).

If there are blackened leaves on the tree, then this is the first sign of a seedling disease. Roots should be healthy (semi-woody, no rot).
It is best to buy grafted seedlings. They are characterized by good drought tolerance and good immunity to certain diseases.

Garden Pest Control

When it blooms, it must be treated with an antibacterial agent. To do this, use, which has a characteristic bluish color.
To prepare this mixture, you will need: 10 liters of water, 100 g of copper sulfate, a little freshly slaked lime and two five-liter dishes (glass, clay or wooden). In one of the vessels you need to mix 5 liters of water and vitriol, and in the other - lime and the rest of the water.

Next, the liquid with vitriol must be poured into a solution of lime in a very thin stream. It is vitriol in liquid, and not vice versa! The result should be a light blue liquid.

Important! Bordeaux liquid can be replaced with fungicides. They also contain copper.

The main point in cooking Bordeaux liquid: do not overdo it with blue vitriol, otherwise there is a risk of burning the flowers.
To test the mixture, you will need a regular nail. It must be immersed in liquid. If you see a red coating on it, then there is a lot of vitriol in the solution, then you need to adjust the concentration of the mixture with the addition of lime.

When the mixture is properly prepared, you can start spraying the pear flowers. On average, 10 liters of solution is enough for 10 seedlings.

It is necessary to take into account the fact that with frequent processing of pears chemicals bacteria develop immunity. They begin to mutate and subsequently cease to die upon contact with these substances.
Rodent control in the garden also reduces the risk of fire blight on the pear tree. Mice and rats that eat tree roots can carry harmful bacteria.