Red Spots on Crabapple Tree Leaves: 5 Causes & What To Do

Crabapple trees are a popular choice for many landscapes due to their beautiful spring blossoms and colorful fruit. But, just like any other plant, they can sometimes have a few problems.

One such issue is the appearance of red spots on the leaves.

The red spots on crabapple leaves could be Entomosporium leaf spot, apple scab, cedar-apple rust, cedar-hawthorn rust, or black rot. To identify the exact cause, you’ll need to consider the specific symptoms. In many cases, removing affected areas and applying fungicides will remedy the issue.

In the following sections, we will explore each of the five possible causes of red spots on crabapple leaves. For each cause, you’ll find a description and solutions to address the issue.

Red Spots on Crabapple Leaves: 5 Causes & Solutions

It can be alarming whenever you discover something abnormal on one of your prized trees. Before you take action, however, it’s best to determine what exactly is plaguing the tree.

1. Entomosporium Leaf Spot (Entomosporium mespili or E. maculatum)

Entomosporium leaf spot is a fungal disease that can cause red spots on the leaves of crabapple trees. These spots may eventually turn brown and may be surrounded by a yellow halo.

Solutions

To manage Entomosporium leaf spot, remove and dispose of fallen leaves, which can harbor the fungus. Fungicides, such as this one, can also be used.

2. Apple Scab (Venturia inaequalis)

Apple scab is another fungal disease that can cause red spots on crabapple leaves. The spots are typically dark and scaly, and they may cause the leaves to curl or become distorted.

Solutions

To manage apple scab, rake and dispose of fallen leaves, which can harbor the fungus. Fungicides can also be used and should be applied in early spring.

3. Cedar-Apple Rust (Gymnosporangium juniperi-virginiana)

Cedar-apple rust is a fungal disease that can cause bright-red spots on the leaves of crabapple trees. The spots may eventually develop into raised, orange-yellow galls.

The disease is caused by the fungus Gymnosporangium juniperi-virginiana, which requires both a juniper and an apple or crabapple tree to complete its life cycle.

Solutions

To manage cedar-apple rust, remove any nearby juniper trees that could serve as a host for the fungus. Fungicides, like this one, can also be used to protect susceptible trees during the spring when the fungus is most active.

4. Cedar-Hawthorn Rust (Gymnosporangium globosum)

Cedar-hawthorn rust is a disease similar to cedar-apple rust, but it can also affect hawthorn trees in addition to crabapples.

As with cedar-apple rust, red spots on the leaves soon develop into orange-yellow galls.

Solutions

To manage cedar-hawthorn rust, similar strategies to those used for cedar-apple rust can be employed.

This includes removing any nearby hawthorn trees that could serve as a host for the fungus and using fungicides to protect susceptible trees during the spring when the fungus is most active.

5. Black Rot (Botryosphaeria obtusa)

Black rot is a fungal disease that can cause red spots on the leaves of crabapple trees.

These spots may eventually turn black, and the disease can also cause cankers on the branches and black rot on the fruit.

Solutions

To manage black rot, prune out and dispose of any infected branches or fruit. Fungicides can also be used and should be applied in the spring when the leaves are emerging.

Understanding the Implications

Red spots on the leaves of your crabapple tree are more than just an aesthetic issue; they can be a sign of a serious disease or infection.

If left untreated, these diseases can weaken the tree, reduce its fruit production, and in severe cases, can even lead to the death of the tree.

Therefore, it’s important to identify and address the problem as soon as possible.

Diagnostic Steps and Problem-Solving

If you notice red spots on your crabapple tree, start by closely examining the spots and the overall health of the tree.

Consider the size, color, and pattern of the spots as well as any other symptoms such as leaf drop, cankers, or poor growth.

You may also want to consider any recent changes in the tree’s care or environment as these can sometimes contribute to disease.

Prevention and Maintenance

Preventing disease is always better than trying to treat it. Keep your crabapple tree healthy by providing proper care, including appropriate watering, fertilization, and pruning.

Regularly inspect your tree for signs of disease, and take action at the first sign of trouble.

If necessary, consult with a professional arborist or your local extension service for help with disease prevention and management.

Related Questions:

What Are the Black Spots on Crabapple Tree Leaves?

Black spots on crabapple tree leaves can be a sign of several different diseases, including apple scab and black rot. Both of these diseases can cause spots that start out red and then turn black.

If you notice black spots on your crabapple tree, it’s important to identify and address the problem as soon as possible.

Why Are the Leaves on My Crabapple Tree Curling?

Curling leaves on a crabapple tree can be a sign of several different problems, including apple scab, fire blight, or pest infestations.

If you notice curling leaves on your crabapple tree, closely inspect the leaves for any signs of disease or pests, and take appropriate action.

Final Thoughts

Red spots on a crabapple tree can be a cause for concern, but with the right knowledge and tools, you can identify and address the problem.

By understanding the potential causes, practicing good tree care, and taking action at the first sign of trouble, you can help keep your crabapple tree healthy and vibrant.

Don’t forget to look into other common problems that Crabapple trees frequently encounter:

• Fungus on Crabapple Trees: 12 Types, Prevention & Treatment
• Yellow Leaves on Crabapple Tree: 12 Possible Explanations