"The verdict is in," Corsica's olive growers federation SIDOC said in a statement. It said Xylella fastidiosa has been detected in the island's olive trees, adding that a lab in western France is working to identify the particular strain.
A strain known as "multiplex" - less virulent than the one that devastated olive groves in Italy in 2015 - has previously been detected in southern France as well as Corsica, but not on olive trees.
However, since wild olive trees cover more than 300,000 hectares of the Mediterranean island, the risk of contamination is "immeasurable", the statement said.
Xylella fastidiosa, spread by tiny sap-sucking insects known as leafhoppers, has also been found on Corsica's holm oaks, which cover more than 100,000 hectares.
"It's the first time that the olive tree and the holm oak have been affected in Corsica," SIDOC president Sandrine Marfisi told the AFP news agency.
Turnover of €3 million
Corsica's olive oil sector has an annual turnover of some 3.0 million euros.
The disease was detected for the first time in Europe in southern Italy's Puglia region in 2013, and has since been found in Spain and Germany as well as France.
Known in the United States as Pierce's disease, it devastated Californian vineyards in the late 19th century.
World olive oil prices surged following a disastrous harvest in 2014-15 in Italy and Spain, the two countries that account for 70 percent of global output, according to the International Olive Council (IOC).
Spain suffered an extremely hot and dry summer in 2014, while Italy was hit with fruit fly infestations as well as Xylella fastidiosa.
Total world output in 2015 of 2.3 million tons was a one-third decrease from the previous year and the lowest level since 2000, the IOC said.