Citrus Canker – Definition & Detailed Explanation – Tree Diseases and Pests Glossary

What is Citrus Canker?

Citrus canker is a plant disease caused by the bacterium Xanthomonas citri subsp. citri. This disease affects citrus trees, including oranges, lemons, limes, and grapefruits, causing lesions on the leaves, stems, and fruit. Citrus canker is highly contagious and can spread rapidly through a citrus orchard, leading to significant economic losses for citrus growers.

How does Citrus Canker spread?

Citrus canker is primarily spread through the movement of infected plant material, such as infected leaves, fruit, or pruning tools. The bacterium can also be spread by wind-driven rain, insects, and animals. Once a citrus tree becomes infected with citrus canker, the bacterium can multiply and spread to neighboring trees, creating a cycle of infection within the orchard.

What are the symptoms of Citrus Canker?

The symptoms of citrus canker vary depending on the severity of the infection. Early symptoms include small, raised lesions on the leaves, stems, and fruit of the citrus tree. These lesions are typically surrounded by a water-soaked margin and may have a yellow halo. As the infection progresses, the lesions can become larger and more numerous, causing defoliation, fruit drop, and dieback of branches.

How is Citrus Canker diagnosed?

Citrus canker can be diagnosed through visual inspection of the citrus tree for characteristic symptoms, such as raised lesions with water-soaked margins. In some cases, laboratory tests, such as bacterial culturing or polymerase chain reaction (PCR) assays, may be necessary to confirm the presence of the bacterium Xanthomonas citri subsp. citri. It is important to consult with a plant pathologist or agricultural extension agent for an accurate diagnosis of citrus canker.

How can Citrus Canker be treated?

There is currently no cure for citrus canker once a tree becomes infected. Infected trees should be removed and destroyed to prevent the spread of the disease to healthy trees. In some cases, copper-based fungicides or antibiotics may be used to help manage the symptoms of citrus canker and reduce the spread of the bacterium. It is important to follow proper sanitation practices, such as disinfecting pruning tools and equipment, to prevent the spread of citrus canker within the orchard.

How can Citrus Canker be prevented?

Preventing citrus canker is key to protecting citrus trees from this devastating disease. Here are some strategies to prevent citrus canker:

1. Plant disease-resistant citrus varieties: Choose citrus varieties that are less susceptible to citrus canker to reduce the risk of infection.
2. Practice good sanitation: Keep the orchard clean by removing fallen leaves, fruit, and debris that may harbor the bacterium. Disinfect pruning tools and equipment between trees to prevent the spread of citrus canker.
3. Monitor for symptoms: Regularly inspect citrus trees for signs of citrus canker, such as raised lesions with water-soaked margins. Early detection can help prevent the spread of the disease.
4. Control insect vectors: Manage insect pests, such as leafhoppers and citrus psyllids, that can spread citrus canker from tree to tree.
5. Follow quarantine regulations: Adhere to quarantine regulations and restrictions on the movement of citrus plant material to prevent the introduction and spread of citrus canker in new areas.

By implementing these preventive measures and practicing good orchard management, citrus growers can help protect their citrus trees from citrus canker and maintain a healthy citrus orchard.