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ARS Home » Pacific West Area » Parlier, California » San Joaquin Valley Agricultural Sciences Center » Crop Diseases, Pests and Genetics Research » Research » Publications at this Location » Publication #315300

Title: Olive quick decline in Italy is associated with unique strain of Xylella fastidiosa

item FICHTNER, ELIZABETH - University Of California - Cooperative Extension Service
item LIGHTLE, DANIELLE - University Of California - Cooperative Extension Service
item Krugner, Rodrigo

Submitted to: Subtropics newsletter
Publication Type: Trade Journal
Publication Acceptance Date: 3/25/2015
Publication Date: 4/1/2015
Citation: Fichtner, E., Lightle, D., Krugner, R. 2015. Olive quick decline in Italy is associated with unique strain of Xylella fastidiosa. Subtropics newsletter. 13(1):2-3.

Interpretive Summary:

Technical Abstract: Olive quick decline syndrome (OQDS) is a destructive new disease currently affecting approximately 20,000 acres of olive in southern Italy—an area approximately the size of California’s table olive production in California. Symptoms of OQDS include extensive branch and twig dieback, yellow and brown lesions on leaf tips and margins, vascular discoloration, and subsequent tree mortality. Similar symptoms have been observed in olives in California, but disease incidence appears to be low when compared to Italy. The causal agent(s) of the disease is still unknown. A number of organisms, including fungi and a bacterium, have been isolated from sick trees in Italy and California. The bacterium Xylella fastidiosa has been found to infect olive trees in both locations. To date, only strains belonging to X. fastidiosa subspecies multiplex have been isolated from olives in California. These California strains have only limited association with the disease, and studies demonstrated that controlled experimental infections did not cause disease in olive varieties commonly cultivated in California. In Italy, recent publications indicate that strains of the bacterium isolated from the outbreak area are closely related to X. fastidiosa subspecies pauca, a subspecies group not known to occur in the United States. The OQDS outbreak in Italy marks the first report of the bacterium in the European Union. Research is underway in Italy to evaluate the role of the bacterium in OQDS.