Cherry Leaf Spot: How To Identify, Treat & Prevent Infection

Having cherry trees in your garden is a delightful experience, as they add beauty with their lovely blossoms and elegant branches.

However, various diseases can occur, one of which is cherry leaf spot. This fungal disease can cause significant damage if not identified and treated promptly.

Cherry leaf spot is a fungal disease caused by Blumeriella jaapii. It primarily affects the leaves of cherry trees, causing purple to brown spots that eventually lead to leaf yellowing and premature drop. If untreated, the disease can weaken the tree and even cause tree death.

In the following sections, you’ll learn all about cherry leaf spot. We’ll discuss its cause and transmission, the tree species it affects, how to identify its symptoms and the long-term prognosis for an infected tree.

Become a cherry tree pro! Explore my in-depth article Cherry Blossom Tree Diseases and Pests to tackle issues like leaf spot and more to ensure a healthy, thriving tree.

Understanding Cherry Leaf Spot

Understanding cherry leaf spot is the first step toward effective management. Here’s what you need to know:

Cherry Leaf Spot Cause and Transmission

Cherry leaf spot is caused by the fungus Blumeriella jaapii. The fungus overwinters in fallen leaves and infects new leaves in the spring when conditions are wet and temperatures are moderate.

The spores are spread by wind and rain splash, and once they land on a susceptible leaf, they can germinate and infect the leaf within hours under favorable conditions.

Susceptible Tree Species

While all cherry trees can get cherry leaf spot, some species are more susceptible than others.

Sweet cherry (Prunus avium) and sour cherry (Prunus cerasus) are often affected as are many ornamental cherry varieties.

Other stone fruit trees, like plums and apricots, can also be affected, although less commonly.

Symptoms & Identification

The first signs of cherry leaf spot usually appear in late spring or early summer as small, purple to brown spots on the upper surface of the leaves.

As the disease progresses, the spots may coalesce, and the leaf may turn yellow and fall prematurely.

In severe cases, nearly all the leaves may drop, leaving the tree bare. The fungus can also infect the fruit and stems, causing similar spots.

Contributing Factors for Disease Development

Several factors can contribute to the development and spread of cherry leaf spot. These include:

• Climate: The fungus thrives in cool, wet conditions. Frequent rain, high humidity, and moderate temperatures (60-70°F) are ideal for its growth and spread.
• Leaf Wetness: The longer the leaves stay wet, the higher the chance of infection. Overhead watering, frequent rain, or high humidity can prolong leaf wetness.
• Overwintering Fungus: The fungus overwinters in fallen leaves, providing a source of infection for the next season.

Long-Term Prognosis for Tree

If detected early and managed effectively, a tree with cherry leaf spot can recover and continue to grow.

However, repeated yearly infections can weaken the tree and make it more susceptible to other diseases and pests. In severe cases, if left untreated, the disease can lead to tree death.

Diseases Often Confused With Cherry Leaf Spot

Cherry leaf spot can sometimes be confused with other diseases that cause similar symptoms. These include:

• Shot Hole Disease: This disease also causes spots on cherry leaves, but the centers of the spots fall out, leaving holes, hence the name “shot hole.”
• Brown Rot: Brown rot primarily affects the fruit, causing it to rot and shrivel. However, it can also cause spots on leaves and blossoms.
• Powdery Mildew: This disease causes a white, powdery coating on the leaves, but in the early stages, it can cause small, purple spots that may be mistaken for cherry leaf spot.

Cherry Leaf Spot Prevention and Management Strategies

Preventing and managing cherry leaf spot involves a combination of good sanitation practices, appropriate use of fungicides, cultural practices, and the use of resistant varieties.

Sanitation Practices

Sanitation is a crucial part of managing cherry leaf spot. The fungus that causes the disease can overwinter in fallen leaves and infected twigs, providing a source of infection for the next season.

Therefore, it’s essential to regularly clean up and dispose of fallen leaves and pruned branches. This reduces the amount of fungus in the environment and can significantly decrease disease pressure.

It’s especially important to do a thorough cleanup in the fall before the first snow.

Fungicide Application

Fungicides can be an effective tool for managing cherry leaf spot, especially in regions where the disease is prevalent.

Fungicides work by protecting new leaves from infection. They are typically applied in the spring when the leaves start to emerge and continued at intervals throughout the season.

The exact timing and frequency of applications depend on the specific product and local disease conditions. Always follow the manufacturer’s instructions when using fungicides.

Some commonly used fungicides for cherry leaf spot include chlorothalonil, myclobutanil, and propiconazole.

Cultural Practices

Cultural practices can also play a significant role in disease management. These practices aim to create an environment that is less favorable for the disease and more favorable for the tree. They include:

Proper Tree Spacing: Properly spacing trees allows for better air circulation, which can help leaves dry out more quickly after rain, reducing the chance of infection.

Pruning: Regular pruning to open up the tree canopy can also improve air circulation and reduce leaf wetness. It also allows more sunlight to reach the leaves, which can help inhibit fungal growth.

Watering: When watering, it’s best to water at the base of the tree rather than from overhead. This helps keep the leaves dry and reduces the chance of infection.

Resistant Varieties

Planting resistant varieties can be an effective way to prevent cherry leaf spot. While no variety is completely immune, some are less susceptible to the disease than others.

For example, some varieties of sweet cherry trees have shown resistance to the disease. Your local extension service or nursery can help you choose a suitable variety for your area.

Integrated Approach

An integrated approach that combines all these strategies will give you the best chance of preventing and managing cherry leaf spot.

This means not relying on a single method but using a combination of sanitation, fungicides, cultural practices, and resistant varieties.

By doing so, you can reduce the disease pressure and keep your cherry trees healthy and productive.

Related Questions:

Is Cherry Leaf Spot Fatal?

Cherry leaf spot can be fatal to a cherry tree if left untreated, especially if the tree is repeatedly defoliated over several years.

However, with early detection and proper management, most trees can recover from the disease.

Can You Treat Cherry Leaf Spot Naturally?

Yes, there are natural methods to treat cherry leaf spot. These include good sanitation practices, cultural practices like proper spacing and watering, and the use of organic fungicides.

However, these methods may not be as effective as conventional fungicides, especially in areas where the disease is prevalent.

Conclusion

Cherry leaf spot is a common disease that can cause significant damage to cherry trees.

However, with a good understanding of the disease and an integrated management approach, you can protect your trees and enjoy their beauty for many years.

The key to managing any plant disease is early detection, proper identification, and timely intervention.

Now that you know how to conquer cherry leaf spot, it’s time to address other common issues. Read these informative guides next:

• Cherry Tree Black Knot Disease | How To Save Your Trees
• Aphids on Cherry Trees: Damage Caused and How To Control