Common Hawthorn Plant Diseases:
How to Identify and Treat

Hawthorn plants (Crataegus spp.) are beautiful additions to any garden or landscape. They are known for their attractive flowers, vibrant foliage, and clusters of red berries. However, like any other plant, hawthorns are susceptible to diseases that can hinder their growth and overall health. In this article, we will discuss some common hawthorn plant diseases, how to identify them, and the treatments available.

1. Fire Blight (Erwinia amylovora)

Fire blight is a bacterial disease that affects a wide range of plants, including hawthorns. It is characterized by wilting, blackening, and shriveling of the blossoms, shoots, and branches. The affected areas may also have a scorched appearance, hence the name “fire blight.”

To identify fire blight in your hawthorn plants, look out for the following symptoms:

• Wilting and blackening of blossoms
• Shoots and branches with a burnt or scorched appearance
• Gum-like ooze coming from infected areas
• Cankers on the branches

To treat fire blight in hawthorn plants:

1. Prune: Remove all infected branches at least 8 inches below the visible signs of infection. Be sure to sterilize your pruning tools after each cut to prevent spreading the bacteria.

2. Disinfect: Use a disinfectant solution (e.g., 10% bleach solution) to clean your pruning tools between cuts.

3. Copper sprays: Apply copper-based fungicides during the dormant season to help control fire blight infections.

2. Cedar-Hawthorn Rust (Gymnosporangium globosum)

Cedar-hawthorn rust is a fungal disease that affects both hawthorns and cedars. It is most prevalent in regions where both of these plants are found. The disease produces orange or rust-colored spots and lesions on the leaves, fruits, and stems of hawthorns.

To identify cedar-hawthorn rust in your hawthorn plants, look out for the following symptoms:

• Orange or rust-colored spots on the upper surface of leaves
• Lesions on the fruits and stems
• Yellowing and premature defoliation

To treat cedar-hawthorn rust in hawthorn plants:

1. Prune: Remove infected branches or stems as soon as you notice the symptoms. Be sure to sterilize your pruning tools after each cut.

2. Fungicides: Apply a fungicide labeled for rust control on hawthorns. Follow the instructions on the label for application rates and timings.

3. Sanitation: Rake up and dispose of fallen leaves and debris from around the hawthorn plants to reduce the chances of reinfection.

3. Leaf Spot Diseases (Diplocarpon spp.)

Leaf spot diseases are caused by various fungi, including Diplocarpon spp., that infect hawthorns. These diseases cause circular, brownish spots with dark margins on the foliage. Severe infections can lead to defoliation and weakened trees.

To identify leaf spot diseases in your hawthorn plants, look out for the following symptoms:

• Circular spots with dark margins on the leaves
• Browning and yellowing of affected leaves
• Premature defoliation

To treat leaf spot diseases in hawthorn plants:

1. Prune: Remove infected branches or stems as soon as you notice the symptoms. Be sure to sterilize your pruning tools after each cut.

2. Fungicides: Apply a fungicide labeled for leaf spot control on hawthorns. Follow the instructions on the label for application rates and timings.

3. Sanitation: Rake up and dispose of fallen leaves and debris from around the hawthorn plants to reduce the chances of reinfection.

4. Powdery Mildew (Podosphaera spp.)

Powdery mildew is a fungal disease that affects many plant species, including hawthorns. It is characterized by a white, powdery coating on the leaves, stems, and flowers of infected plants. Severe infections can stunt the growth of hawthorns and reduce their overall vigor.

To identify powdery mildew in your hawthorn plants, look out for the following symptoms:

• White, powdery coating on leaves, stems, and flowers
• Curling and distortion of affected leaves
• Stunted growth

To treat powdery mildew in hawthorn plants:

1. Prune: Remove infected branches or stems as soon as you notice the symptoms. Be sure to sterilize your pruning tools after each cut.

2. Fungicides: Apply a fungicide labeled for powdery mildew control on hawthorns. Follow the instructions on the label for application rates and timings.

3. Cultural practices: Ensure proper air circulation around hawthorn plants by spacing them adequately. Avoid overhead watering as it can promote the spread of powdery mildew.

Conclusion

Hawthorn plants are susceptible to various diseases that can affect their health and appearance. By familiarizing yourself with the common diseases that affect hawthorns and knowing how to identify and treat them, you can ensure the continued vitality and beauty of your hawthorn plants. Regular monitoring, timely pruning, and appropriate fungicide applications can go a long way in preventing and managing these diseases. Remember to always follow label instructions when using any chemical treatments on your plants.