How to treat bacterial canker on cherry trees
How to deal with bacterial canker in cherry trees
"What's wrong with my cherry tree?"
That's what a neighbour asked me recently. He knew his cherry tree wasn't thriving and wanted me to have a look. One glance and I knew there was a problem. A big one. Goop was oozing out of all sorts of nooks and crannies in the cherry tree, even though the poor thing had still managed to produce some cherries.
This was, sadly, the tree's swan song. That's because the owners had waited too long to treat the symptoms of bacterial canker in their beloved cherry tree.A cherry tree with bacterial canker on its trunk. There was little that could be done to save this tree, as the disease had spread throughout it. (Photo credit: OrchardPeople.com).
What is Bacterial Canker in Cherry Trees?
Bacterial canker is a disease that affects cherry, plum, and other related fruit trees. The symptoms can be wide ranging and include sunken patches on the trunk and branches. Those sunken patches often release a sticky, gummy substance. Other symptoms of bacterial canker include branch dieback, which occurs when the new shoots at the ends of the tree's branches die suddenly.
Affected trees may also have brown spots on the leaves. When the dead tissue in the centre of the spot falls away, it leaves an empty hole. This is referred to as "shothole" because it looks like tiny pellets were shot through the cherry tree's leaves.
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How to Treat Bacterial Canker in Cherry Trees
Bacterial canker doesn't just look bad; it can also take a toll on the health of your tree so it needs to be controlled. Luckily, bacterial canker can easily be pruned out of a tree if the pruning is done correctly.
Snip off the diseased branch and dispose of it in a sealed bag in your garbage. Do not not put it in the compost, where the canker can continue to spread. Afterwards, meticulously sterilize your pruners and move on.After you prune out cherry tree branches with bacterial canker, it's essential to sterilize all your pruning tools. If you do not properly disinfect your tools, you may spread the disease to other trees that you use the pruners on in the future.
What Happens When You DO NOT Prune Bacterial Canker off Your Fruit Tree?
Pruning works when you catch the problem early on. But when you leave canker on your tree, it will continue to spread from branch to branch, and from tree to tree in your community.
If you let things go too far, and canker is oozing out of the trunk of the tree and off all of the branches, this tree can be a liability and should be cut down. After you cut down the tree, dig out it's root system, as this may also be infected.
Bag it up and seal the bags. Put the remains in the garbage. Start again next year with a new tree, and in a new hole, since some of the canker may survive in the soil where the diseased tree once was.If you find bacterial canker on your cherry tree, prune out the diseased branches, bag them up, and remove them from the site - do not put them in your compost pile. In this situation, we had to remove an entire tree, as the canker had spread around the tree and through the trunk and roots.
Examples of the Successful Treatment of Bacterial Canker in Apricot Trees
There are times when you can save a tree that has canker in its trunk - that is, when it just has a small spot of canker. We successfully treated an apricot tree in Ben Nobleman Park Community Orchard by carefully scraping the canker away from the infected spot, using a clean boxcutter as our knife. Our tree recovered and is thriving today.In the case of this apricot tree in Ben Nobleman Park Community Orchard, we were able to carefully scrape out the damaged tissue from the trunk with a clean boxcutter, right down to the deadwood in the tree. We ensured all of the diseased tissue fell onto a sheet and not onto the soil, so we could remove the pathogen from the site. The tree recovered perfectly and over the years, the wound healed.
This year, canker has reared its ugly head again elsewhere - in our park's two oldest and most beautiful cherry trees. It has hit a number of the tree's thicker limbs.
When it comes to pruning off diseased branches on fruit trees, timing is important. If we were to prune off those thick branches in the autumn, the wounds would not have time to heal before the winter.
Luckily, as trees go dormant in the winter, so do fruit tree pests and diseases. So winter is an excellent time to prune off diseased branches. To learn more about when to prune fruit trees click here.
After pruning off the diseased branches, we may also treat our trees with copper spray to help prevent the spread of the disease. You can learn all about how to prune your fruit trees and protect them from pests and diseases in my premium online fruit tree care courses.
And the moral of the story for organic fruit tree growers? It's essential to know how to recognize fruit tree diseases so you can treat them early on. And the best time to learn more is while your tree is still young and healthy!
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Director, OrchardPeople.com Fruit Tree Care Education Online
Susan Poizner is an urban orchardist in Toronto, Canada and the author of Grow Fruit Trees Fast and Growing Urban Orchards. Susan trains new growers worldwide through her award-winning fruit tree care training program at Orchardpeople.com. Susan is also the host of The Urban Forestry Radio Show and Podcast and an ISA Certified Arborist.
Cherry (Prunus spp.)-Bacterial Canker | Pacific Northwest Pest Management Handbooks
- Plant Disease
- Host and Disease Descriptions
Diseases Caused by Pseudomonas syringae
Cherry, Flowering (Prunus spp. ) - Bacterial Canker
Cause Pseudomonas syringae pv. syringae, a bacterium. This disease can be the limiting factor against establishing a cherry orchard anywhere in the Pacific Northwest. Although the bacteria survive on the outside of the plant they must get inside and multiply in the space between plant cells (apoplast) to cause disease. These pathogenic bacteria inject several proteins and small-molecule toxins to get past host immune mechanisms. Once inside, the bacteria induce a watery, nutrient rich environment between the plant cells where they can multiply and continue colonization of the plant tissues. Bacteria also produce a protein that acts as an ice nucleus, increasing frost wounds that bacteria easily colonize and expand. Factors that weaken or injure the tree predispose it to developing cankers. These factors include wounds, frost damage, early dormant season pruning, heading cuts, incorrect soil pH, and poor nutrition. Important avenues of infection leading to tree death include natural leaf scars in the fall and heading cuts made in the spring after planting a new orchard. Infection by other pathogens including Cytospora, Verticillium, and Nectria can lead to more bacterial canker. Ring nematodes have also been associated with increased susceptibility to bacteria canker in both cherry and peach. Sources of bacteria include old cankers, healthy buds, systemic infections within trees (with or without cankers), as epiphytes on leaf surfaces, weeds, grasses, and even soil. Wind, rain, insects, infected bud wood, and infected nursery stock can spread bacteria. Pruning through cankered and then through susceptible, healthy tissue does not spread the disease.
Although bacterial canker is more serious on sweet cherry trees, it also affects almonds, apricots, peaches, plums, and prunes. The same bacterium also can cause a blight of many other fruit, vegetable, and ornamental crops.
The cherry cultivars Royal Ann, Bing, Lambert, Napoleon, Sweetheart, and Van are very susceptible to bacterial canker. The cherry cultivars Corum, Regina, Rainier, Sam, and Sue appear to have sufficient tolerance to canker to be grown commercially without serious tree loss. Mazzard seedlings, particularly the F12-1, can be used as resistant rootstocks. Size controlling rootstocks may also have useful resistance but field performance trials are lacking. Scions on Gisela 6 rootstock have exhibited increased susceptibility. The cherry cultivars Royal Ann, Bing, Lambert, and Van are quite susceptible to dead bud. 'Black Republican' and 'Mazzard' seedlings are somewhat less susceptible.
Symptoms The most conspicuous symptoms are cankers, gum exudation, and dieback of girdled branches. Dead buds and leaf spots also can occur. In most cases, heavy gumming is associated with bacterial canker formation on branches and twigs. Gumming occurs at the cankers' margins. Other problems can lead to gumming (see Cherry Prunus spp. - Gumming).
Cankers caused by the bacteria may be on the trunk, limbs, and twigs. Typical cankers are much longer than broad, but a canker may girdle the infected limb or trunk. The cambium at the canker will be discolored and necrotic. Use a pocket knife to reveal this discolored tissue. Cankers develop in winter and early spring. As the tree begins growth in spring, the bacteria population declines and a callus layer forms around the canker's edge. During spring and summer, girdled and nearly girdled limbs may leaf out. Normally, leaves turn yellow, then the limbs usually die. In some instances, these symptoms may not appear until late summer when the leaves' water requirement is high.
Dead bud "disease" is first noted as dying buds on spurs in spring. Infected buds usually start to die in February. As the disease progresses, both leaf and flower become infected. Dead bud usually starts in lower limbs and moves up the tree and to adjacent trees in successive years. Often, trees in the lower orchard, where air drainage is poor, are the first to be infected. If all buds on a spur are killed, the spur will die back next season. Cankers very seldom form, but the diseased buds may produce a slight gumming. Repeated death of buds may result in misshaped growth and sometimes fasciation. In severe cases, 90% or more of buds on a tree may be killed.
Leaf and fruit spots are not common and are not numerous if they develop. Spots on leaves are at first water soaked, then become dry and brown. Spots on fruit are dark to black and depressed or pitted.
Cultural control Bacterial canker is best managed through the use of many different tactics.
- Plant resistant cultivars and/or rootstocks. For example, F12-1 Mazzard rootstock with scions from virus-tested (and found to be free of all known viruses), canker-free trees has been very useful. Make buds or grafts at least 12 to 15 inches away from the trunk. Mazzard seedling rootstocks have also been useful.
- Do not interplant new trees with old trees, which are a major source of the bacteria.
- Locate orchard in an area less likely to be affected by frost. If planting in the spring, plant orchards after date that frost is likely to have occurred. Prevent winter injury by painting trunks white and avoiding late season fertility.
- Test soil for ring nematodes before planting. Also test for pH and other physical characteristics that can be corrected prior to planting.
- Provide optimal soil conditions for growing cherries including attention to pH and nutrition. Annually monitor for adequate nutrient levels such as nitrogen. Keep irrigation off above ground parts for the first few years.
- Control weeds.
- Delay dormant pruning until January or February. Summer pruning is even better and should be after harvest, when weather is dry. Make heading cuts after planting only during dry weather when rain will not occur for at least a week after pruning. Make heading cuts close to a lateral bud.
- Completely remove infected trees or branches girdled and killed by cankers. Do not allow trees to regrow from roots or trunks left after a major trunk canker has been removed.
- In summer, small cankers may be cut out using the following method. Cut away bark above and around the edges of the infected area. Use sharp tools, and leave wound margins smooth and neat. Wounds should be left uncovered to dry out during the summer. Try not to have sprinkler irrigation soak the wounds. Sterilize all pruning tools between cuts with an appropriate disinfectant.
- Cauterizing cankers using a hand-held propane burner has been used with some success in New Zealand.
- Scoring tree trunks has been practiced by Willamette Valley, Oregon growers for several years. Grower testimonials point to some benefits but there has been no research on the efficacy of the practice. A sharp pocket knife is used to make a vertical shallow cut in the tree trunk. The resulting wound tissue that develops is supposed to resist canker development and prevent trunk girdling. Knives should be disinfected between trees.
Chemical control Copper-based products have not worked well under conditions favorable for disease development. Bacteria resistant to copper products have been detected throughout our cherry growing regions, which compromises chemical control tactics. In small plot disease control trials it is not unusual to find copper-treated trees with more disease than trees without any treatment. Heavy use of copper products is not recommended as concentrations in the soil can build up to toxic levels after several decades of use. Resistance to antibiotic can develop quickly even with minimal use. Minimize the use of Kasumin by using it to protect trees after planting when making heading cuts and once during early flowering.
Focus on cultural control tactics first and supplement with chemical control. Traditional recommendations encourage the first spray to occur in October before fall rains followed by another application in early January. Growers should consider adjusting the timing of sprays to coincide with leaf fall. Thorough coverage is needed. Protecting heading cuts made after planting a new orchard is also important. Protect both orchard and nursery trees (sweet cherry, prune, and plum). Some growers use low rates of copper-based products during bud break to reduce symptoms of dead bud.
- Copper-based products have not worked well and are discouraged due to the prevalence of resistant bacteria and at times increased disease.
- Badge X2 at 3.5 to 14 lb/A. Group M1 fungicide. 48-hr reentry. O
- Bonide Liquid Copper Fungicide at 0.5 to 2 fl oz/gal. H
- Bordeaux 12-12-100. O
- Champ WG at 8 to 16 lb/A. Group M1 fungicide. 48-hr reentry.
- C-O-C-S WDG at 8 to 15.5 lb/A plus dormant spray oil. Group M1 fungicide. 48-hr reentry.
- Copper-Count-N at 6 quarts/100 gal water. Use only 2 to 3 quarts/100 gal water during bloom. Group M1 fungicide. 48-hr reentry.
- CS 2005 at 51.2 to 64 oz/A. Group M1 fungicide. 48-hr reentry.
- Cueva at 0.5 to 2 gal/100 gal water/A. Group M1 fungicide. 4-hr reentry. O
- Cuprofix Ultra 40 Disperss at 5 to 8 lb/A. Group M1 fungicide. 48-hr reentry.
- Kocide 3000 at 3.5 to 7 lb/A plus 1 pint superior-type oil/100 gal water. Group M1 fungicide. 48-hr reentry.
- Monterey Liqui-Cop at 1. 5 teaspoons/gal water. H
- Nordox 75 WG at 5 to 13 lb/A. Group M1 fungicide
- 12-hr reentry. O
- Nu-Cop 50 DF at 8 to 16 lb/A. Group M1 fungicide. 48-hr reentry. O
- Dart at 64 fl oz/100 gal water during late dormancy. Spray with continuous agitation. 24-hr reentry. O
- Kasumin 2L at 64 fl oz/A in 100 gal water after planting when making heading cuts and once during early flowering. Do not use alternate-row applications, or within 30 days of harvest. Do not use in orchards fertilized with animal manure. Not for nursery production. Group 24 fungicide. 12-hr reentry.
- Rex Lime Sulfur Solution (28%) at 6 to 12 gal/100 gal water delayed dormant may have some utility. 48-hr reentry. O
- Vacciplant at 14 to 60 fl oz/A plus an effective bactericide. Can be used day of harvest. Unknown efficacy in the PNW. Group P4 fungicide. 4-hr reentry.
- Surface disinfectants such as OxiDate 2.0 at 0.25 to 2.5 gal gal/100 gal water are registered but have very short residual activity. Efficacy of these products has not been extensively tested in the PNW. Frequent use (every few days) is on the label, which still may not be effective during conditions favorable for bacterial growth and infection.
Biological control Although registered, the few that have been tested on similar diseases in the Willamette Valley have had none to poor efficacy.
- Aviv (Bacillus subtilis strain IAB/BS03) at 10 to 30 fl oz/100 gal water. Do not tank mix with more than one product. Unknown efficacy. Preharvest interval not specified. 4-hr reentry. O
- Double Nickel 55 (Bacillus amyloliquefaciens strain D747) at 0.25 to 3 lb/A. Unknown efficacy. Group BM02 fungicide. 4-hr reentry. O
- Serenade ASO (Bacillus subtilis strain QST 713) at 2 to 4 quarts/A. Active ingredient is a small protein. Unknown effectiveness in the PNW. 4-hr reentry. O
- Serenade Garden Disease Control Concentrate at 2 to 4 fl oz/gal water. Unknown effectiveness in the PNW. H O
- Triathlon BA (Bacillus amyloliquefaciens strain D747) at 0.5 to 6 quarts/100 gal water. Group BM02 fungicide. 4-hr reentry. O
References Kennelly, M.M., Cazorla, F.M., de Vicente, A., Ramos, C., and Sundin, G.W. 2007. Pseudomonas syringae Diseases of Fruit Trees: Progress Toward Understanding and Control. Plant Disease 91:4-17.
Lillrose, T., Lang, G.A., and Sundin, G.W. 2013. Strategies to minimize bacterial canker in high density sweet cherry orchards. Acta Horticulturae 1161:457-462.
Spotts, R.A., Wallis, K.M., Serdani, M., and Azarenko, A.N. 2010. Bacterial canker of sweet cherry in Oregon-Infection of horticultural and natural wounds, and resistance of cultivar and rootstock combinations. Plant Disease 94:345-350.0005 Rusta tree of cherries
A healthy cherry orchard is a guarantee of a rich harvest of beautiful and tasty cherries. Experienced gardeners take preventive measures to ensure cherry trees have a healthy vegetative environment to prevent cherry diseases and keep the garden healthy. After all, prevention is always better than cure, and this rule works for trees too!
This article will focus on preventive measures to protect cherries from the most common diseases, as well as operational methods of treating trees in your garden. You should know that competent measures to combat cherry diseases, carried out in a timely manner, will restore health and yield to your cherry orchard.
Let's list what diseases gardeners face most often, what are the signs of these cherry diseases, how to deal with them, and what is the prevention.
Symptoms of infection with clasterosporiosis (fruit stigmina) are already noticeable in early spring. Spotted red spots appear on the leaves, which eventually turn brown. These spots, which quickly reach a diameter of up to 5 millimeters, are surrounded by a blurry raspberry border, which distinguishes this type of fungus from other infections. As a result of the development of this fungal infection and local drying of the leaf, holes appear in the area of \u200b\u200bthese spots, after which the leaf itself dies.
In addition to leaves, cuttings, buds, flowers, fruits and whole young shoots are affected, with red borders increasing in length. Gum disease is observed. Severely affected sprouts quickly die and fall off. The darkened flowers fall off, the buds turn black and secrete gum, but, dying, remain on the branches. According to such clear signs, even a novice gardener can make a correct diagnosis for perforated spotting.
Prevention and treatment of clasterosporiasis / stigmine fruit:
- cut off diseased branches and shoots to capture a healthy area. Treat the cut points with a saturated solution of 1% copper sulphate in combination with a 3% solution of iron sulphate; after drying, coat the cut with garden pitch or natural drying oil;
- after the destruction of the affected parts of the tree, all the remains of the tree are immediately burned, the place of the fire is dug up;
- The affected tree with a large infestation should be sprayed twice with a 3% aqueous solution of Bordeaux liquid.
It is believed that the fungus that caused this disease arrived from Scandinavia around the middle of the 19th century and managed to spread widely, thanks to its natural survival, which allows it to endure even severe and prolonged frosts on fallen and unharvested leaves. Weakened trees often suffer from coccomycosis.
Obvious signs of damage appear on the leaves, which are covered with brown dots, gradually turning into spots. The spores of this parasite are formed on the underside of the leaves when they are covered with a pink-white bloom. Leaves die and fall off. Cherry fruits of an infected tree are covered with multiple small dots, deformed and lose their taste.
Therapeutic and preventive measures against coccomycosis are identical to those for perforated spotting. When choosing cherry seedlings, give preference to varieties of modern breeding that can significantly resist coccomycosis. Such trees will need fewer treatments for fungal infections.
Gray rot - cherry moniliosis
This disease was discovered in the European part of Russia no more than half a century ago and has three names: gray rot, monilial burn and moniliosis. This fungal parasite has access to all parts of the cherry tree and mercilessly kills it. Branches and trunks of cherries affected by moniliosis look like they have been burned by fire.
Infection starts from the leaves, later the bark of the tree is covered with chaotically arranged gray growths. At their location, wood decay begins. Covered with a fungus, the branches crack and become covered with gum and die. The formed cherry fruits are deformed and almost all crumble. The moniliosis mycelium hibernates on the branches affected by it, and if you do not resort to preventive measures, it will successfully live up to the heat and continue its pernicious work.
The fungal pathogen lives in diseased parts of the tree. Here he will overwinter well, if preventive maintenance is not done in a timely manner.
Measures to combat and prevent moniliasis:
- cut off the affected branches and shoots 10 centimeters below the infection boundary, and disinfect the cut points and cover with garden pitch or natural drying oil;
- collect and burn all fallen parts of the diseased tree;
- strip the bark of affected parts of the tree trunk down to healthy wood;
- treat with an aqueous solution by spraying the whole tree to choose from: Bordeaux liquid, iron vitriol, copper sulfate, nitrofen, oleocuprite.
Gum is a clear, sticky liquid that tends to solidify into a resinous mass. It arises from the places of defeat by fungal diseases. The cause of gum disease can be excessive watering of the soil and excessive feeding of cherry trees.
Gum disease must be fought. Since the liquid contains pathogenic spores, they will spread to healthy plants by rain and wind. The treatment of gum disease of cherries is to prevent such a condition of the tree, no matter how trite it may sound. First of all, proper care is needed, the destruction of pests, the timely detection of diseases and their treatment.
Cherry tree rust
The spores of Thekopsora padi fungus, which causes cherry rust, are based in the cones of bushes and trees of spruce species (spruce, juniper), from where they are dispersed with air currents and rains spread over fruit trees.
Rust infection results in reddish spots on the leaves of cherry trees, bordered by a yellow rust-like outline. On the surface of the sheet, these signs appear more clearly than on its reverse side.
Measures for the treatment and prevention of cherry rust:
- for the purpose of prevention, remove coniferous plantations in contact with cherries;
- carefully collect and burn falling leaves;
- spraying with an aqueous solution of fungicide "Khom" containing copper oxychloride, at the rate of: 80 grams of the drug per bucket of water - immediately after flowering gives a good therapeutic effect against rust;
- Spraying after harvesting cherries with a 1% solution of Bordeaux mixture will consolidate the positive effect of cherry rust control.
Cherry necrotizing ringspot virus (PNRSV)
Symptoms of necrotizing cherry ringspot depend on the strain of the virus and the susceptibility of the cherry cultivar. In spring, rings or spots of chlorotic color form on cherry leaves, this is the main sign of damage to the garden. Some strains of the PNRSV virus can cause very serious losses in the cherry crop.
Necrotic ringspot virus can cause stunting of trees in the garden, leading to the death of buds and shoots on cherries. Such viral infections greatly impair the growth of cherry trees, while at the same time reducing resistance to other diseases.
Necrotic ringspot virus prevention
- Use only healthy seedlings.
- Uprooting and destruction of affected cherry trees.
- Spatial isolation between trees.
PNRSV can be particularly severe from May to June during the cherry growing season. Treatment for necrotizing ringspot virus involves cutting and destroying infected shoots, and sometimes uprooting entire trees. Treatment with chemicals against this virus is not used.
This disease of cherries, which is caused by a pathogenic fungus or bacteria, takes a heavy toll on the health and yield of cherries. Prolonged wet weather favors the spread of this infection, and the onset of infection coincides with the flowering period of the tree.
Such cherry disease as scab is manifested by brown-olive velvety spots on the surface of the leaves. Cherry berries also suffer: green ones wrinkle and do not develop, while ripe ones crack, becoming unfit for consumption.
Measures for the prevention and treatment of scab
- spraying the entire cherry tree and near-stem soil with nitrafen;
- Treat the trees with Bordeaux liquid on the opening buds at the rate of: 100 grams of the drug per 10 liters of water;
- repeat the previous treatment 3 weeks after flowering;
- after harvesting the berries, spray with Bordeaux liquid for the third time;
- severe infection of cherries also provides for the fourth stage of treatment with Bordeaux mixture two weeks after the third spraying.
Prevention of cherry diseases and their consequences
The universal and optimal requirement for the care and prevention of dangerous cherry diseases is the observance of all agrotechnical measures to maintain its normal vegetation.
- carefully collect and burn all plant waste in case of cherry disease in the garden area, do not leave them for wintering as a refuge for infection and pests;
- it is safer to prune diseased parts of the cherry tree in dry autumn weather before leaf fall to minimize the dispersion of disease-causing fungal spores with rain and wind;
- at the beginning of the growing season, in the middle of spring, revise weakened, withered or thickening crown branches and shoots, which will provide more ventilation, lighting, additional nutrition for the whole tree and increase its resistance to infection by fungi and viruses;
- when fertilizing the near-stem zone, monitor the absence of weeds on it;
- protect the cherry stem from mechanical damage. If this could not be avoided, then remove the injured parts, clean the wounds, cover with a layer of garden pitch, natural drying oil or light-colored children's plasticine;
- to timely prevent both frostbite and sunburn of the bole of cherry trees. To do this, they must be whitewashed in early spring and late autumn;
- be sure to immediately remove the gum, followed by the treatment of the whole tree with Bordeaux liquid, which will stop the process of gum production, which is dangerous for the spread of fungal diseases;
- before bud break and after flowering, spray fruit trees with 1% solution of Bordeaux mixture, do this a third time two weeks after the second treatment; good results are obtained by the same annual treatment in the fall after leaf fall;
- Before treatment with chemicals, especially Bordeaux liquid, tests should be carried out for the burn reaction of the tree, that is, spraying a small part of the tree with an appropriate solution, in which a necrotic burn spot may appear, the leaf and fruit seem to be covered with a net. In this case, the processing time must be postponed and the test repeated after a certain time.
Tips for protecting the cherry orchard after treatment
After successfully fighting diseases of the cherry tree, the level of correct agro-technical work with this tree should not be reduced in order to preserve its productive potential;
- Fruit from the treated tree must be thoroughly washed under running water before use;
- In modern specialized stores today you will be offered the safest for humans and effective drugs against infections and pests;
- We remind you of the high toxicity of copper sulfate. If it is impossible to replace it with another means of protection, then at least use the best personal protective equipment: glasses, masks, clothes, shoes, do not smoke or eat while processing trees. Less dangerous, for example, the drug "fundazol", especially during cherry blossoms;
- It is necessary to strive to keep the crown as full as possible so that the tree is more resistant to frost.
Described in this article fungal diseases of cherries can threaten almost all fruit trees in the garden, and not just stone fruits , damage the crop, divert the gardener's strength and time and cause some damage to the budget. In this regard, all of the above measures for the prevention and direct control of the disease that has arisen in the cherry orchard should be combined with a complete set of agricultural techniques for caring for fruit trees.
Bacterial fruit canker
Bacterial canker - a disease that affects apple, pear and cherry trees.
Bacterial canker in temperate climates is the most common bacterial disease of fruit plants. pear , apple tree and other crops suffer the most from it - much less.
Bacterial cancer primarily infects plants that are weakened, damaged by frost, suffering from drought or excess moisture in the soil. The main gates of infection are various mechanical damage to the bark, bud and leaf traces, it can be transmitted through insect pests and during grafting, if the cutting is taken from an infected plant.
Manifestation of the disease.
This disease manifests itself in two different forms : in the form of the death of leaves and young shoots that turn black and dry up, remaining hanging on the branch, the death begins from the edges of the leaves, gradually covering the entire plate, with spots on the petioles. The tip of a young, non-lignified shoot curves in a hook-like manner. No secretions, raids on the surface of leaves and branches are observed.
The second form manifests itself in the form of the withering away of areas of the bark on the trunk and branches of the tree. Severely affected trees dry out.
It is impossible to completely cure bacterial cancer : the bacterium that causes it lives in the tissues of the whole tree and is inaccessible to remedies. For containment, copper preparations are mainly used: copper sulfate, Bordeaux liquid, copper oxychloride, Azofos, Medex (one of the best remedies for bacterial diseases).
We carry out preventive treatments against infection with bacterial cancer in early spring, during bud break, and in autumn, during leaf fall. Do not forget about protection from pests that can "bring" the disease from the outside.
If the plant is already sick, then we treat it with one of the above drugs immediately after the first signs of the disease appear. We spray at least 2-3 times per season with an interval of 10-14 days, not forgetting to withstand 3 weeks from the moment of the last treatment to harvest. We “feed” the plant well, not forgetting about trace elements, and we monitor the irrigation regime. In this case, the disease practically does not manifest itself.
Antibiotics of the streptomycin series can help in the fight against bacterial cancer, but they are prohibited for use both here and abroad, since for treatment it is necessary to apply them regularly and in large quantities so that the drug literally soaks the entire plant, including fruits. Therefore, their use is justified only in exceptional cases and only for trees that have not yet begun to bear fruit.
The cause of the disease is a pathogen on the affected organs and in the soil of the trunk circle.
Increased development of the disease occurs due to trauma to the bark (due to frost or mechanical damage), as well as humid or very hot weather.
Control methods. When to protect trees?
1. Period of dormant buds - early spring period.
Pruning of trees, thinning of the crown with the removal of shrunken, diseased branches with a healthy tissue capture of at least 10 centimeters.
Treat the instrument after each cut with 10% formalin solution. Remove cut branches from the garden and burn.
Cancer wounds on trunks and branches should be cleaned to healthy tissue and disinfected with 1% copper sulphate solution, apply therapeutic putty.
Duration: period of dormant buds - early spring period (phenophases: winter dormancy and swelling).