Epidemiology and control of Verticillium wilt on olive

Verticillium wilt on olive is an increasing disease because of changing conditions for olive growing, especially irrigation and high-density planting. The disease is widely distributed in all olive-growing regions of the world, and is one of the major limiting factors in olive oil production. Disease symptoms are associated with two Verticillium dahliae pathotypes: the defoliating pathotype, which is distributed across large areas where cotton has been previously grown, and the non-defoliating pathotype, which is distributed across fields where mainly potato has been cultivated prior to olive planting. The disease can be spread by using V. dahliae-latently infected seedlings, by contaminated water, and by bad sanitation. Partial and limited control of the disease can be obtained by soil solarization, organic amendments, green manure, and biological control agents. The use of resistant or tolerant cultivars available within large collections in the Mediterranean basin may also assist in preventing outbreaks of the disease. Control of Verticillium wilt on olive is an ongoing challenge that requires an integrated approach combining all available means and developing new ones.