Why is my plant oozing resin or gum?

The production of resin or gum is a defense mechanism used by many woody plants when they are damaged or infected. This symptom is especially common in stone fruit trees, citrus trees, and other woody plants, and is usually associated with diseases affecting the bark or the crown of the trunk. Correctly identifying the cause of gummosis is essential to apply the appropriate treatment and prevent the problem from worsening.