Q: Can you tell me what this is on my grapefruit tree and how to get rid of it?
A:Β Unfortunately, your grapefruit tree has a disease commonly called gummosis (Phytophthora species). This disease is common in the soil and may be introduced through wounds or cracks in the bark. A contributing factor is irrigation. Flood irrigation or systems that consistently spray water on the trunk of the tree can not only weaken the bark but also provide a liquid pathway for the fungi to move from the soil into the tree. One of the signs we see is the oozing from cracks in the bark as the disease moves through the tree. Sometimes we also see bark sloughing off as branches succumb to the disease. Some trees will live a few years with this disease and you can help by spraying fungicide on actively oozing areas. In other cases, the tree may die within a year. Once the disease spreads to the trunk and/or most the tree, it is time to plan for its removal.
Peter L. Warren is the Forest Health Program Coordinator for the Arizona Department of Forestry and Fire Management. Questions, photos and videos may be emailed toΒ tucsongardensage@gmail.com
