Few tree species are as beautiful as the cherry. The annual pink flowers make practically every other tree look like the ugly duckling in comparison.
Sadly, the cherry tree is not always blossoming and looking its best. Tons of cherry tree diseases could be affecting it. And here, we want to show you everything about them.
Whether you’re planting this tree at home or someone you know is experiencing how their tree struggles, it could be from any of these pathogens. We want you to understand how they occur, what they produce, and how they can be treated.
Below we explain all of this plus a lot more. Take a look!
What Causes Trees to Get Diseases?
Let’s start with an important question – how do trees get sick in the first place?
Well, it happens almost the same way it happens to humans. Either the trees catch something in the environment, they get weak, or both at the same time. Here’s a bit deeper explanation to consider:
Root & Body Damage
One of the most common reasons trees contract diseases is damage to their roots, trunks, leaves, or branches. When they get damaged from physical or environmental causes, infections are likely to happen. Bacteria and viruses get into the tree directly through wounds using wind or soil.
Drought or Overwatering
When the roots receive too little water, they get dry. This dryness puts the tree into stress, lowering its capacity to fight pathogens. Similarly, when the roots receive too much water, fungus and rot happen, which invites pathogens to infect the tree more easily.
Overcrowding & Other Trees
A tree can also contract an infection by being in contact with other trees or plants. If a tree is too close to other plants, it won’t grow and develop as needed. This could make it more susceptible to diseases. At the same time, being too close to infected plants increases the chances of infection.
Lack of Nutrients
Like a tree that doesn’t receive proper water, it can also be affected by a lack of nutrients. Poor soil can also cause the tree to get stressed and weaken over time. This makes it vulnerable to a wide array of diseases.
10 Common Diseases that Affect Cherry Trees
With a better idea of why and how trees get infected with diseases, it’s time to learn how these diseases happen, what they cause, and how you can help the tree accordingly. Check them out:
1. Black Knot
One of the most common diseases is the black knot. It affects many different tree species, going from the plum and apricot to the chokecherry trees. But cherry is the most common vessel for this disease.
What Does Black Knot Do?
Known scientifically as the “Dibotryon morbosum” or “Apiosporina morbos,” this disease causes swellings on the branches, twigs, and sometimes the trunk of a tree. These swellings resemble knots, thus the common name. And each knot can achieve a black or olive-green color.
The swelling could affect the blossoming and fruiting of the plant. It could make twigs and branches fall, not grow leaves, and dry up after dying.
How Does Black Knot Happen?
It happens thanks to the pathogens that come from wind or rain. They carry this knot fungus and germinate in weaken trees. This often occurs in the spring, when plants are starting to blossom. Once fall arrives, the knots appear.
The pathogen is so fast that it can infect a tree in as little as 6 hours. Even worse, they can grow to 6 inches in size by fall.
How to Get Rid of Black Knot?
The only way to remove the disease is to prune away infected parts by about 4 inches away from the knots. Any twigs and branches with the fungus need to be cut out.
All the residues should be burned or buried to prevent future infections. More importantly, the infected parts should all be pruned away without fault.
2. Bacterial Canker
Probably one of the most dangerous diseases, it is bad enough to possibly kill entire trees if not treated. It can happen to many species, going from the cherry to the apricot, peach, and plum tree.
What Does Bacterial Canker Do?
It attacks branches by wilting and weaken them, often causing the death of the limb. Similarly, it attacks leaves, covering the surface with dark spots and often leaving large holes across.
This disease may also cause gum with an amber color and kill entire trees if not treated properly.
How Does Bacterial Canker Happen?
The “Black pycnidia” and “Pseudomonas syringae pv. morsprunorum” are what produce this disease. They infect trees via wounds in the branches or trunk, even though it can also enter the organism through leaf scars.
The bacteria are more likely to spread and infect diseases in rainy and windy places. Yet, it can’t infect healthy trees – only damaged and weakened ones.
How to Get Rid of Bacterial Canker?
Because the bacterial canker is likely to happen when the tree is under drought stress or lack of nutrients, it is worth healing the tree to make the disease disappear. However, pruning affected parts is also useful.
This disease prefers temperatures over 90 degrees Fahrenheit. In colder climates, it will likely disappear automatically.
3. Powdery Mildew
One of the most common diseases on trees, powdery mildew, happens to tons of different species. It is not the worst in terms of effects, but it can be challenging to get rid of.
What Does Powdery Mildew Do?
As the name says, it causes a powder-like effect on leaves. It attacks mainly young cherry leaves that haven’t developed resistance to the disease. This powder may distort, pale away, and sometimes twist the leaves. While it develops further, it could kill the leaves over time.
How Does Powdery Mildew Happen?
Depending on the tree, it comes from several variations of fungi. For the cherry tree, it is the “Podosphaera clandestine” that causes it.
It mainly starts from ascospores, types of spores that attach to young and sprouting leaves. When rainy and windy seasons arrive, these spores spread around and produce the fungus, given the conditions.
How to Get Rid of Powdery Mildew?
One of the main reasons powdery mildew happens is unnecessary irrigation. For that reason, it is always recommended not to overwater any cherry tree, especially in the spring.
Having said that, the only way to get rid of it is to prune infected leaves. As preventative measures, you can consider fungicides and proper irrigation practices. Keeping water away from leaves also works.
Also, this disease loves temperatures between 70 and 80-degrees Fahrenheit. Keeping the tree in colder environments could also cure it.
4. Necrotic Ringspot
A dangerous disease that’s often confused with bacterial canker, it affects many tree species but hits cherries especially hard.
What Does Necrotic Ringspot Do?
The main symptom of this disease is a yellowing/browning of the leaves. Like bacterial canker, it may cause holes that completely change the appearance. Sometimes, this bacterium can spread to the twigs and buds, killing entire limbs.
In some cases, the disease may be so advance as to stunt the growth of the plant. It can also cause the cherry to produce fewer fruits, mature more slowly, or grow with deformations.
How Does Necrotic Ringspot Happen?
This virus’s scientific name is “Prunus necrotic ringspot virus,” as it affects most Prunus family trees (apricots, peaches, almonds, plums, cherries, etc.)
It often spreads through seeds and pollen. But it could also come from wood grafting and wind.
How to Get Rid of Necrotic Ringspot?
There’s no way to cure trees that have this disease. It is recommended to remove the tree altogether if you want to stop the disease’s spread into other specimens.
5. Crown Rot
One of the worst diseases any cherry tree can have is crown rot. Also called collar rot, it comes from one of the most stubborn and dangerous bacteria, the “Phytophthora.”
What Does Crown Rot Do?
It produces a wide array of symptoms, from poor growth, fragile twigs and leaves, to small and deformed fruits. The disease spreads fast and can cause a tree’s total death within months or even weeks of infection.
The primary way to know whether a tree is infected is to look at the roots and the trunk base. If it seems decayed or rotten, that’s a great sign of crown rot (it looks dark-brown and smells of fungus)
How Does Crown Rot Happen?
The pathogen is called “Phytophthora spp.” and it mainly comes from an excess of moisture. Soils that don’t drain well or absorb too much water will cause cherry trees to be more susceptible to this bacterium through the root collar or crown.
It spreads through soils and can live years, even in winters and extreme heat, affecting several generations of the same species.
How to Get Rid of Crown Rot?
There’s no way to get rid of the disease once a tree is infected. But it can be prevented by managing the soil properly, ensuring proper draining and low watering frequency.
Fungicides can also prevent bacteria from spreading. However, the strength and sturdiness of the bacteria often make it challenging to get rid of.
It’s recommended to avoid planting new trees in places that have been affected by the bacteria in recent years.
6. Crown Gall
Also known as the cancer of trees, the crown gall affects everything from their roots to their trunks, twigs, and sometimes leaves. It is a dangerous and possibly life-threatening disease.
What Does Crown Gall Do?
A common problem with gall is the appearance of tumors. These tumors typically start in the roots and can spread across an entire tree. The tumors are often fleshy, white, brown, or tan, killing the plant if the disease gets too advanced.
How Does Crown Gall Happen?
The disease comes from the “Agrobacterium tumefacines” or more recently named “Rhizobium radiobacter” bacteria. It infects trees through wounds and often comes directly from the soil, especially poorly drained and alkaline ones.
Like cancer, this disease absorbs the plant’s DNA and transforms the cherry’s cells into tumor cells. Thus the galls start to grow.
How to Get Rid of Crown Gall?
The only way to remove the disease is to spread a chemical solution that stops the gall’s spread across the tree. However, it is always recommended to avoid it in the first place as getting rid of it can be extremely hard.
For that, plant only in healthy soils (no previous sign of the disease) and away from plants that have it. Also, the disease thrives in warm temperatures, so growing cherries in environments of less than 50 degrees Fahrenheit can also prevent it.
Also found as the Cherry Buckskin disease, it mostly affects the plant’s fruits, and unlike other diseases on the list, it spreads from insects. Also, it affects all Prunus trees.
What Does X-Disease Do?
Probably the most typical symptom is a slow growth of fruit, along with smaller and paler yields. But it can also cause tree decline to the point of life-threatening it by affecting the rootstock in the first place.
Some cherries may develop red tinges in limbs. It may also cause the total death of branches and leaves if the disease gets too advanced. Luckily, this often happens slowly over several years.
How Does X-Disease Happen?
The disease comes from phytoplasma organisms coming from infected cherry leafhoppers. This disease doesn’t come from the air or soil.
How to Get Rid of X-Disease?
Pruning visually infected limbs and leaves are the best way to prevent the spread of the disease. The pruned sections should be burned or buried deeply. In trees where the disease is too advanced, the only way to fix it is to bring it down before it infects others.
To prevent it, experts recommend stopping leafhoppers from growing around by taking away weeds and other leafhopper-attracting plants. A fungicide may also prevent the spread of the disease.
8. Brown Rot
Affecting fruits and leaves mainly, brown rot is another typical disease of the cherry family. It attacks all cherries but happens more commonly on the Kwansan cherry, a flowering variety.
What Does Brown Rot Do?
It mostly starts when the trees are blossoming, attacking the leaves and fruits directly. As the name says, it causes browning of the fruit and leaves, sometimes producing complete death of the affected parts. Sometimes, the browning becomes fungi, causing a powdery substance to grow on leaves and fruits.
Trees with brown rot can lose entire harvests and leaves at the same time.
How Does Brown Rot Happen?
The name of the bacteria is “Monilinia fructicola.” It comes directly from spores that travel through the wind. In some cases, the pathogens may come from insects and birds.
Generally, it happens when the right conditions make it possible: warm and wet environments. And it affects leaves and blossoms directly. The infection can occur in 3 hours.
How to Get Rid of Brown Rot?
There’s no way to cure a tree with brown rot when the fruits are already affected. But when limbs and leaves start to show signs of browning, pruning them and burning them is always helpful. This only works before the tree blossoms or produces fruits.
To prevent it, keep the tree in an aerated and windy place, preferably in cold temperatures where the fungus is less likely to happen.
9. Cherry Leaf Spot
Almost all species from the cherry family can get affected by the leaf spot disease. But it mostly happens on the sweet, tart, and English Morello. It can also affect plum trees. You can also call it the shothole or yellow leaf disease.
What Does Cherry Leaf Spot Do?
As the name says, it affects the leaves directly. It causes small spots with a brown to purple color. These spots may eventually grow to the point of covering more than half of the leaves, sometimes browning them out thoroughly.
The spots tend to cause the leaves to dry out and fall after several weeks. Severe infections may kill more than half the tree’s leaves. Even worse, it may cause the fruits to grow smaller, have a milder taste than usual, or not grow at all. Severely advanced cases may cause tree death.
How Does Cherry Leaf Spot Happen?
The disease comes from the fungi “Blumeriella jaapii.” It typically starts in dead leaves in winter. The fungi eventually produce spores that travel through the wind or rain and germinate on healthy leaves.
It may also spread from tree to tree and even across different species, including the plum.
How to Get Rid of Cherry Leaf Spot?
Removing infected leaves is the most effective way to prevent the bacteria from spreading. More importantly, burning all fallen infected leaves is an even better option, as these lay the spores even faster.
To avoid the disease from even happening, it’s excellent advice to keep the cherry tree under heavy sunlight where the fungi are less likely to grow and spread.
10. Silver Leaf
Another usual fungal disease is the silver leaf. It affects all trees from the Prunus family, including apricots, plums, and cherries. Yet, it can also affect apples.
What Does Silver Leaf Do?
It’s very similar to the Cherry Leaf Spot. But instead of small dark spots on the leaves, it produces a silver tone. Over time, the silver-tone on the leaves becomes brown, meaning they’re starting to die.
Some leaves may look ordinary from the front, but their underside is often dark. This is another sign of silver leaf.
And when the disease advances too far, it causes conks or small mushroom-like tumors on the trunk or branches.
Either way, the disease can escalate to the point of reducing annual yield and killing the tree slowly over the years.
How Does Silver Leaf Happen?
The bacteria that produce the fungus is called “Chondrostereum purpureum.” It typically spreads through tissue (wounds on the tree). Yet, it often starts in the branches and/or leaves directly.
This often happens when conks on other trees or plants start to spread using the wind or rain. The toxins that circulate usually attach to the leaves of other trees.
How to Get Rid of Silver Leaf?
The treatment starts by removing conks and/or dark leaves. Pruning them away to the point where they aren’t visible anymore should fix the problem.
Even when pruned, the disease may get sick again the next year. For that reason, it is worth pruning in temperatures under 32 degrees Fahrenheit where the bacteria can’t spread. Also, try only wounding the tree in dry conditions.
Learning all about these usual cherry tree diseases will give you a better idea of what to be aware of when growing one.
More importantly, it may help you give any tree its life back before the disease gets worse. And if it’s too late, it may at least help you prevent it from spreading to other trees.
Either way, don’t hesitate to consider all the advice and information above before taking any action. With our guidance, preventing the disease or curing it before it’s too late will be a lot easier.