Orange Tree Diseases

Orange trees, like any other plant, are susceptible to a variety of fungal, viral and bacterial infections that affect their leaves, fruit, bark and existence. Orange trees originate from Southeast Asia, only growing in hot, tropical and subtropical climates, which are rich with fungi, bacteria and viruses.

Citrus Phytophthora Gummosis

Citrus gummosis is a fungal infection, which makes the tree appear to bleed by forming small cracks in the bark, where sap oozes from the tree. These cracks spread around the circumference of the tree, drying out the bark so it cracks further and falls to the ground.

Greasy Spot

Greasy spot is a fungal infection that causes yellow-brown blister spots on leaves that develop an oily appearance. The leaves eventually fall off the tree. This disease spreads by releasing spores.

Exocortis

Exocortis, or "scaly butt," is a viral infection that occurs in citrus trees, producing severe cracks in the bark, which causes the bark to flake off. This virus can also cause yellowish blotches on the leaves.

Citrus Canker

Citrus canker is a bacterial disease characterized by raised white scabs or lesions on the tree and fruit that drip with the bacteria during rain. The disease spreads through rainstorms that carry the bacteria, entering the plant through a wound in the bark or branch.

Tristeza

Citrus Tristeza is a viral infection that destroys the tree within a few years. Symptoms include yellowing, wilting and stem pitting. Brown and melon aphids spread this disease after feeding on an infected tree.

References

• Citrus Canker
• Citrus Phytophthora Gummosis
• Citrus Tree Care

Resources

• Orange
• Exocortis: Description and Background
• Citrus Tristeza Virus: Symptoms and Control