Citrus Exocortis: A Disease Affecting Citrus Trees
Introduction
Citrus exocortis is a disease that can affect citrus trees, especially those with a specific rootstock called trifoliate. While trees without this rootstock are generally safe, there’s still a chance they can become infected. To prevent this disease, it’s essential to use clean rootstock.
What is Citrus Exocortis?
Citrus exocortis, also known as scalybutt disease, was discovered in 1948 and is primarily recognized as a bark shelling disease. It damages the bark, causing it to dry out, crack, and peel off the tree in thin strips. This process is known as shelling. It mostly occurs on citrus trees with trifoliate rootstock but can also affect other types.
The disease is caused by viroids, which are even smaller and simpler than viruses. Viroids spread from infected budwood to healthy budwood, often through tools like pruning clippers.
Symptoms of Citrus Exocortis
The most common symptoms of citrus exocortis include:
- Bark shelling, often at the base of the trunk
- Stunted growth of the tree
Depending on the type of citrus tree, other symptoms may include:
- Spots on the leaves
- Yellowing leaves
- Yellow spots on twigs
Effects of Citrus Exocortis
While the disease does not affect the quality of citrus fruit, it can reduce yield due to stunted growth.
Prevention and Management of Citrus Exocortis
Unfortunately, there is no cure for citrus exocortis. However, it can be prevented or managed through the following measures:
- Prevention: Choose trees that are certified to be disease-free. This ensures that the nursery used clean budwood and rootstock.
- Management: If you notice signs of the disease in your home orchard, you can still harvest a decent yield of high-quality citrus. However, it’s crucial to prevent the disease from spreading to other trees. Disinfect equipment used for pruning with bleach after working on an infected tree.
Additional Information
- Citrus exocortis is a highly contagious disease that can spread rapidly through a citrus grove.
- The disease can also affect other citrus rootstocks, such as sour orange and grapefruit.
- Research is ongoing to develop resistant citrus varieties and more effective management strategies.
Conclusion
Citrus exocortis is a serious disease that can impact the health and productivity of citrus trees. By understanding the disease, its symptoms, and the available prevention and management strategies, growers can minimize its effects and protect their citrus groves.
