Bacterial leaf scorch, the same bacteria that was responsible for the death of Oleanders and grape vines, is attacking old grove olives in Southern California, particularly the Irvine and Newport Coast areas. There is no cure for this disease. Nursery grown olives such as “Swan Hill” are not nearly as susceptible. This disease is also occurring on Liquidambar and Purple Leaf Plum trees. The entire host range is huge, but in our area these are the primary concerns.
Decreased water movement causes symptoms that often look like water stress or nutrient deficiency. Symptoms are most noticeable in summer and fall during periods of heat and water stress. There may be delayed spring growth, or very little growth. The tree may look like it needs more water when it doesn't. Symptoms may include:
• Chlorosis (yellowing of leaves)
A small bacteria that lives and multiplies inside of the xylem vessels of plants.
How is it spread?
By leafhoppers called Glassy-winged Sharpshooters which arrived in California in 1990.
Keep your plants healthy and properly irrigated. Have your olive trees inspected at least twice per year.