Cherry tree enthusiasts look forward to it each spring: a mass explosion of light pink blossoms. What’s not so exciting for lovers of the blossoms and their sweet fruit is the threat of cherry tree diseases. If you’ve noticed signs of disease, we’ve collected symptoms and causes for the seven most common cherry tree diseases and how to treat them.
Signs of disease can be frightening. These pathogens can harm an entire orchard of cherry trees, putting a full halt to any charming blossoms or juicy fruit. However, when cherry tree growers execute the right preventive measures, they decrease their trees’ susceptibility to infection and increase the chances of a vigorous bloom and delicious harvest.
Cherry Trees Affected: A common ornamental cherry tree disease, black knot also affects most Prunus varieties, including edible and native types. Black knot-resistant cherry tree varieties include East Asian cherry, North Japanese hill cherry, and Prunus maackii (Manchurian cherry or Amur chokecherry).
Symptoms: Black knot (Dibotryon morbosum) appears as hard, black swellings or knots, which may stretch 1-6 inches on the tree. These knots appear in various areas around the tree and enlarge when the disease is left untreated.
Velvety, olive-green fungal growth may cover the knots. Diseased twigs often bend due to knot overgrowth. Infected branches may wilt, not grow leaves, and can eventually kill the entire tree.
Causes: Through spring and summer, mature knots produce spores. The rain and wind then carry the black knot fungus spores to susceptible plants.
The spores can germinate and infect new plants in six hours at the optimal temperature and wet conditions. By fall, light brown swellings appear on infected twigs. The following spring, the growing knots develop the olive-green fungal growth. As the year progresses into summer and fall, the knots become hard, rough, and black.
Treatment: Prune 3-4 inches below the knot during the dormant season. Sterilize all pruning equipment. Burn or bury all infected material; otherwise, it may still be able to infect healthy trees. Remove cherry trees that have a severe infection.
The Wisconsin Horticulture Division of Extension does not recommend using fungicides since treatment is expensive and likely to be ineffective.
Risk: Black knot can limit the production of cherries and ruin the appeal of ornamental cherry trees.
Cherry Trees Affected: Brown rot is a problem for the Kwanzan flowering cherry tree — as it is one of the most susceptible cultivars. It is also a common weeping cherry tree disease. Many stone fruits, including peach and plum trees, are also affected.
Symptoms: Brown rot (Monilinia fructicola) symptoms first occur as the browning of blossoms and the death of twigs. Leaves on the infected twigs turn brown and collapse but remain attached to the tree.
When wet weather conditions are right, powdery masses of brown-gray spores may be visible on infected fruits, flowers, or twigs.
Causes: If the infected blossoms do not drop off, the infection can spread from the flower to the neighboring twig. Twigs then develop cankers, which further produce fungal spores of the disease.
Brown rot thrives best in warm, wet conditions, causing infection to occur in as little as three hours. Insects can act as spreading agents for this fungal cherry disease.
Treatment: Once brown rot infects your cherries, there are no curable treatments for the fruit. Prune any affected parts of the tree with sanitized pruning tools 4 to 6 inches below the sunken dead tissue. Burn or bury the pruned materials to prevent the infection from spreading.
Thinning your fruit trees encourages airflow, allowing for a drier environment to deter the fungus. If brown rot is unmanageable and continues to infect your trees, consider using fungicides.
Cherry trees can fall victim to several diseases that negatively impact their health appearance and productivity. Being able to accurately identify these diseases is crucial for taking proper care of your cherry trees. Pictures provide a useful visual reference for recognizing and diagnosing common cherry tree diseases. In this article, we’ll explore some key diseases affecting cherry trees, using pictures to spotlight the symptoms.
Common Diseases That Damage Cherry Trees
Cherry trees are susceptible to various fungal bacterial, and viral diseases. Some of the most prevalent include
- Black knot
- Powdery mildew
- Brown rot
- Bacterial canker
- Cherry leaf spot
- Phytophthora root rot
These diseases can damage leaves, branches, trunks, roots, and fruits. If left unchecked, they can severely weaken and potentially kill cherry trees. Understanding what to look for is vital for early intervention.
Recognizing Cherry Tree Diseases Through Photographs
Pictures provide an invaluable resource for identifying diseases based on visual symptoms. Here are photos of common cherry tree diseases to assist with recognition:
Black Knot
Black knot manifests as rough, elongated black swellings on branches. These knots enlarge progressively, sometimes girdling and killing branches.
Black knot disease on a cherry tree branch
Black knot disease on a cherry branch
Powdery Mildew
Powdery mildew appears as a white or gray powdery coating on leaves, shoots, and fruits. Leaves may become distorted and drop prematurely.
Cherry leaves covered in white powdery mildew
Powdery mildew infection on cherry leaves
Brown Rot
Brown rot causes infected fruits to rot and turn brown or grayish-brown. Advanced infections may show fungal spore growth.
Cherry fruit with brown rot infection
Cherry fruit exhibiting brown rot symptoms
Bacterial Canker
Bacterial canker leads to oozing cankers on branches and trunks. Cankers appear sunken or cracked with reddish exudate.
Cherry tree canker oozing reddish sap
Weeping cherry tree canker due to bacterial infection
Cherry Leaf Spot
Cherry leaf spot manifests as small purple or brown spots scattered across leaf surfaces. Spots may fall out leaving a shot hole pattern.
Cherry tree leaf with purple leaf spot lesions
Cherry leaf exhibiting small purple leaf spot lesions
Causes of Cherry Tree Diseases
Fungal Pathogens
Fungi such as Apiosporina morbosa (black knot), Podosphaera clandestina (powdery mildew), and Monilinia species (blossom blight, brown rot) are behind many cherry tree diseases. They thrive in wet conditions.
Bacterial Infections
Bacteria including Pseudomonas syringae (bacterial canker) invade trees through wounds, spreading fastest in cool, wet weather.
Viral Pathogens
Viruses like Little Cherry Virus-2 infect trees via insect vectors and propagation, resulting in poor fruit quality and reduced vigor.
Preventing and Managing Cherry Tree Diseases
Cultural Practices
- Choose disease-resistant varieties
- Prune for open canopy
- Disinfect pruning tools
- Promote airflow
- Water at soil level
- Clean up fallen leaves/fruit
- Use preventive fungicides
Remedial Measures
- Prune out infected parts
- Apply fungicides to protect healthy tissue
- Remove severely infected trees
Familiarizing yourself with the appearance of common cherry tree diseases can make identification easier. Use pictures as a visual guide for spotting issues early. Preventive care, prompt treatment, and working with experts when needed gives cherry trees the best chance of overcoming diseases. With knowledge and vigilance, you can maintain the health of your cherry orchard.
FAQ About Common Cherry Tree Diseases
Cherry tree leaves usually turn brown from improper watering, weather stress, or cherry diseases such as cherry leaf spot or brown rot.
What Cherry Trees Are Black Knot-Resistant?
Black knot-resistant cherry tree varieties include East Asian cherry, North Japanese hill cherry, and Prunus maackii (Manchurian cherry or Amur chokecherry).
Cherry Tree Diseases | Cherry tree fungus
FAQ
How do you identify a cherry tree disease?
Identifying Symptoms of Cherry Tree Diseases
Changes in leaf color, such as yellowing, browning, or reddening, often indicate disease presence. Wilting leaves, especially during adequate soil moisture, can signal root-related issues like Phytophthora Root Rot.
What does a fungus on a cherry tree look like?
What Are The Symptoms Of Cherry Tree Fungus? It can vary based on the fungus. Black swellings or knots, silver leaves, light powdery patches, depressed cankers, and leaves falling off are all signs of a problem.
How to fix a diseased cherry tree?
This involves removing diseased leaves from the ground around the tree in late winter or spring to eliminate the source of overwintering inoculum. However, when disease is severe, a season-long fungicide spray program is also necessary for effective control.
How to tell if a cherry tree is dying?
A quick way to check is by scratching the bark with a fingernail or a knife to expose the cambium; a bright green color shows that part of the plant is alive, but a brown or dull green cambium color indicates that it is probably dead.