Cherry Blossom Tree Diseases, Pests and Common Problems

Cherry blossom trees, known as Sakura, are renowned for their stunning yet fleeting flowers. Unfortunately, they are susceptible to a range of illnesses and infestations.

This guide will provide an overview of the most common issues affecting cherry blossom trees along with tips for identifying and managing these problems.

Key Takeaways

  • Common diseases include leaf spot, blight, powdery mildew, and canker.
  • Diseases can be managed through good sanitation practices, the use of fungicides, and maintaining overall tree health.
  • Pests such as aphids, spider mites, caterpillars, and beetles can cause significant damage.
  • Pests can be managed by introducing natural predators, using insecticides, and maintaining tree health.
  • Common problems include yellowing or browning leaves, oozing sap, poor flowering, and stunted growth. These can often be managed by checking water and nutrient amounts and correcting disease or pest issues.

Feeling overwhelmed by how much there is to learn about your cherry tree? Don’t be! I explain all about the key care needs, potential problems and what to do, best varieties, and much more in my detailed Guide to Cherry Blossom Trees.

Ornamental Cherry Tree Diseases

Ornamental cherry trees can be affected by a range of diseases. These diseases can cause a variety of symptoms, including spots on the leaves, blight, mildew, and more.

Early identification and appropriate treatment are crucial for maintaining the health and beauty of these trees.

1. Cherry Leaf Spot

Cherry leaf spot is a fungal disease that causes small, purple, or brown spots on the tree leaves. As the disease progresses, these spots may grow larger and the leaves may yellow and fall off.

To manage this disease, remove and dispose of any fallen leaves, and consider applying a fungicide during the growing season.

2. Cherry Blossom Blight

Cherry blossom blight, also known as blossom wilt, can cause the flowers and young shoots of the tree to wilt and turn brown.

This disease is caused by a fungus that can overwinter in fallen leaves and twigs.

To prevent this disease, practice good sanitation by removing and disposing of any plant debris. Fungicides, such as this one, can also be used for prevention and control.

3. Other Blight Diseases

There are several other blight diseases that can affect cherry trees, including Botryosphaeria canker and blight and bacterial canker. These diseases can cause wilting, cankers, and dieback.

Management strategies include pruning and disposing of infected branches, improving tree vigor through proper watering and fertilization, and in some cases, applying appropriate fungicides or bactericides.

4. Powdery Mildew

Powdery mildew is a common fungal disease that appears as a white, powdery coating on the leaves, stems, and flowers of the tree.

While it rarely kills the tree, it can weaken the tree and make it more susceptible to other diseases.

Powdery mildew can be managed by improving air circulation around the tree, applying a fungicide (this one works well), and removing and disposing of any infected plant material.

5. Black Knot Disease

Black knot disease is a fungal disease that causes black, swollen growths on the branches of the tree. These growths can girdle the branches, causing them to die.

To manage black knot disease, prune and dispose of infected branches during the dormant season, and consider applying a fungicide in the spring.

6. Cherry Shot Hole Disease

Cherry shot hole disease, also known as Coryneum blight, is a fungal disease that causes small, round holes in the leaves of the tree, giving them a “shot hole” appearance.

This disease can be managed by removing and disposing of any fallen leaves, improving tree vigor through proper watering and fertilization, and applying a fungicide during the growing season.

7. Brown Rot

Brown rot is a fungal disease that primarily affects the fruit of the tree, causing it to rot and turn brown. The fungus can also infect the flowers and shoots of the tree.

To manage brown rot, remove and dispose of any infected fruit, prune to improve air circulation, and consider applying a fungicide.

8. Silver Leaf

Silver leaf is a fungal disease that causes the leaves of the tree to take on a silvery sheen. Over time, the disease can cause branches to die back.

To manage silver leaf, prune and dispose of infected branches during the dormant season, and avoid wounding the tree as the fungus can enter through wounds.

9. Canker

Canker diseases can cause sunken, dead areas on the bark of cherry trees. These cankers can girdle branches, leading to wilting and dieback.

Cankers are often caused by stress, so maintaining tree health through proper watering, mulching, and fertilization can help prevent these diseases.

If cankers do appear, prune and dispose of the affected branches.

10. Fire Blight

Fire blight is a bacterial disease that can cause branches to appear as if they’ve been scorched by fire. The disease can spread rapidly and can be fatal if not controlled.

To manage fire blight, prune and dispose of infected branches (making sure to sterilize pruning tools between cuts), apply antibacterial sprays, and consider planting resistant varieties.

11. X-Disease

X-disease, also known as cherry buckskin disease, causes leaves to yellow and curl and can lead to a decline in tree health over several years.

This disease is spread by leafhoppers, so managing these pests can help prevent the disease. Infected trees should be removed to prevent the disease from spreading to other trees.

12. Crown or Root Rot

Crown or root rot is caused by various fungi that thrive in poorly drained soils. Symptoms include wilting, yellowing leaves, and a general decline in tree health.

To prevent root rot, plant cherry trees in well-drained soil, and avoid overwatering. Infected trees may need to be removed to prevent the disease from spreading.

13. Crown Gall

Crown gall is a bacterial disease that causes large, tumor-like growths on the roots and lower trunk of the tree.

These galls can disrupt the flow of water and nutrients, leading to declining tree health. There is no effective treatment for crown gall, so prevention is key.

Avoid wounding the tree as the bacteria can enter through wounds, and consider planting resistant varieties.

14. Verticillium Wilt

Verticillium wilt is a soil-borne fungal disease that can cause wilting, yellowing leaves, and branch dieback.

This disease can be difficult to manage because the fungus can persist in the soil for many years.

To prevent verticillium wilt, avoid planting cherry trees in areas where susceptible plants have been grown in the past, and consider planting resistant varieties.

15. Necrotic Ringspot

Necrotic ringspot is a viral disease that causes rings or arcs of dead tissue to appear on the tree’s leaves. This disease is spread by a variety of insects and through infected pruning tools.

To manage necrotic ringspot, control insect pests, sterilize pruning tools between cuts, and remove and dispose of any infected leaves.

Ornamental Cherry Tree Pests

Just like any other trees, ornamental cherry trees can be a target for various pests.

These pests can cause a variety of problems, from leaf damage to more serious issues like stunted growth or even death of the tree.

Early identification and appropriate treatment are crucial for maintaining the health and beauty of these trees.

1. Aphids

Aphids are small, soft-bodied insects that feed on the sap of cherry trees, causing the leaves to curl and turn yellow.

They also excrete a sticky substance called honeydew, which can lead to the growth of sooty mold.

To manage aphids, consider introducing beneficial insects like ladybugs and lacewings, which are natural predators of aphids. In severe cases, insecticidal soaps or oils can be used.

2. Spider Mites

Spider mites are tiny pests that can cause the leaves of cherry trees to turn yellow and fall off.

They are often found on the undersides of leaves and can be identified by the fine, silken webs they produce.

To control spider mites, increase humidity around the tree, introduce natural predators, or use a miticide like this one if the infestation is severe.

3. Caterpillars

Several species of caterpillars can feed on the leaves of cherry trees and cause significant damage. These include the tent caterpillar, the gypsy moth caterpillar, and others.

To manage caterpillars, handpick them off the tree, or use a biological insecticide containing Bacillus thuringiensis (this one is very effective).

4. Ants

While ants don’t typically damage cherry trees, they can protect and farm aphids for their honeydew, leading to larger aphid populations.

To manage ants, use ant baits or barriers to prevent them from climbing the tree.

5. Cherry Bark Tortrix

The cherry bark tortrix is a moth whose larvae burrow into the bark of cherry trees, causing the bark to crack and the tree to become susceptible to diseases.

To manage this pest, prune and destroy infested branches, and consider using a pheromone trap to catch and monitor adult moths.

6. Cherry Fruit Fly

The cherry fruit fly lays its eggs in the fruit of cherry trees. The larvae then feed on the fruit, causing it to rot.

To manage this pest, use yellow sticky traps to catch adult flies, and consider applying an appropriate insecticide when the flies are active.

7. Borers

Borers are a group of insects that lay their eggs in the bark of cherry trees. The larvae then bore into the wood, causing wilting and dieback.

To prevent borers, keep trees healthy as borers are more likely to infest stressed trees. If borers are present, infested branches may need to be pruned and destroyed.

8. Scale

Scale insects are small pests that attach themselves to the branches and leaves of cherry trees, feeding on the tree’s sap. They can cause the leaves to yellow and drop prematurely.

To manage scale, introduce natural predators, prune and destroy infested branches, or use a horticultural oil or insecticide.

9. Japanese Beetles

Japanese beetles are a significant pest of cherry trees. The adults feed on the leaves and flowers, and the larvae feed on the roots.

To manage Japanese beetles, handpick them off the tree, use pheromone traps to catch the adults, or apply a suitable insecticide.

10. Leafhoppers

Leafhoppers are small, wedge-shaped insects that feed on the sap of cherry trees, causing the leaves to yellow and curl. They can also spread diseases.

To manage leafhoppers, introduce natural predators, use insecticidal soaps or oils, or consider using a suitable insecticide in severe cases.

11. Thrips

Thrips are tiny insects that feed on the leaves and flowers of cherry trees, causing discoloration and distortion. They can also spread viral diseases.

To manage thrips, introduce natural predators, use insecticidal soaps or oils, or use a suitable insecticide in severe cases.

12. Slugs

Slugs can cause significant damage to young cherry trees by feeding on the leaves and bark.

To manage slugs, use slug traps or bait, handpick them off the tree, or consider using a suitable molluscicide.

13. Cherry Sawfly

The cherry sawfly is a small insect whose larvae feed on the leaves of cherry trees, often leaving only the veins behind.

To manage this pest, handpick the larvae from the tree, or use a suitable insecticide.

A sawfly larva affixed to the bottom of a leaf rib.

14. Leafminers

Leafminers are the larvae of certain flies, moths, and beetles that feed inside the leaves of cherry trees, causing distinctive trails or blotches.

To manage leafminers, introduce natural predators, prune and destroy infested leaves, or use a suitable insecticide.

15. Leaf Rollers

Leaf rollers are the larvae of certain moths that feed on cherry tree leaves, often rolling them up and securing them with silk.

To manage leaf rollers, introduce natural predators, handpick the larvae from the tree, or use a suitable insecticide.

16. Bark Beetle

Bark beetles are small insects that bore into the bark of cherry trees, often causing significant damage.

To manage bark beetles, keep trees healthy as stressed trees are more likely to become infested.

If bark beetles are present, infested trees may need to be removed and destroyed to prevent the beetles from spreading.

Ornamental Cherry Tree Common Problems

In addition to diseases and pests, ornamental cherry trees can also experience various other problems.

These can be caused by environmental factors, improper care, or physiological issues.

Understanding these common problems can help you maintain the health and beauty of your cherry trees.

1. Yellowing or Browning Leaves

Several issues, including nutrient deficiencies, overwatering, underwatering, or disease, can cause yellowing or browning leaves.

To manage this problem, ensure that your tree is receiving the right amount of water and nutrients, and check for signs of disease or pests.

2. Oozing Sap

Oozing sap, or gummosis, can be a sign of stress, injury, or disease. If your tree is oozing sap, check for signs of pests or disease, and ensure that the tree is not being overwatered or underwatered.

In some cases, a tree may need to be pruned or treated with a fungicide.

3. Poor Flowering

Poor flowering can be caused by a few issues, including improper pruning, insufficient light, or nutrient deficiencies.

To encourage your tree to flower, ensure it receives enough light, prune it correctly, and provide a balanced fertilizer (I use this one).

4. Early Leaf Loss

Early leaf loss can be a sign of stress or disease. If your tree is losing its leaves early, check for pest or disease issues, and ensure that it receives the right amount of water and nutrients.

5. Bark Damage

Bark damage can be caused by pests, disease, or physical injury. If your tree’s bark is damaged, check for signs of pests or disease, and protect the tree from further injury.

6. Leaf Curling

Leaf curling often can be a sign of pest infestation or disease.

If your tree’s leaves are curling, check for signs of pests or disease, adjust your watering schedule, and have a soil test performed to check nutrient levels.

7. Stunted Growth

Stunted growth can be caused by a variety of issues, including nutrient deficiencies, poor soil conditions, or disease.

To encourage growth, test your soil and fertilize based on recommendations. Also, look for disease or pest symptoms, and treat any issues appropriately.

8. Lack of Fruit Production

Lack of fruit production can be caused by improper pollination, insufficient light, or stress.

To encourage your tree to produce fruit, ensure that it is receiving enough light, provide it with a balanced fertilizer, and consider planting another cherry tree nearby to aid in pollination.

It’s possible that your particular variety is purely ornamental and was not bred to produce any fruit.

Final Thoughts

Ornamental cherry trees can face a variety of diseases, pests, and other problems. However, these issues can be managed and prevented with proper care and attention.

By understanding the common issues that can affect your tree and knowing what to do when problems arise, you can ensure that your ornamental cherry remains healthy and beautiful for years to come.