Growers and advisors are seeing a possible new oil olive disease. Research has identified a pathogen that could be causing defoliation, leaf lesions and elongated twig lesions.
University of California Cooperative Extension Orchard Systems Advisor Dani Lightle says there’s a new disease popping up in olive trees. “There have been some trees reported in the San Joaquin Valley with severe decline and defoliation,” Lightle says. “Looking into that, we were able to isolate a new pathogen that we haven’t yet seen in olives up until recently. We are now surveying across the state and trying to see what we are dealing with.”
More research is needed before experts can say definitively if this pathogen is causing the new symptoms; however Lightle shared some of the symptoms growers are currently finding in trees. “There are sort of two main symptoms that we see associated. The first is kind of a necrotic spot in the leaves that doesn’t really have the colorful zonate pattern that peacock spot has. It will have a round spot, but not quite look like peacock spot,” Lightle says. “The second are sort of purple, elongated lesions in the twigs and branches.”
Find out more about the disease at the Sacramento Valley Orchard Source website.