10th INTERNATIONAL VERTICILLIUM SYMPOSIUM 16-20 ...

AN OUTBREAK OF VERTICILLIUM WILT IN HEDGEROWOLIVE ORCHARDS IN ANDALUCÍA (SOUTHERN SPAIN)LÓPEZ-ESCUDERO, F.J. (ag2loesj@uco.es), ROCA, L.F. (ag3rocal@uco.es),TRAPERO, A. (ag1trcaa@uco.es) AND BLANCO-LÓPEZ, M.A. (ag1bllom@uco.es).Grupo de Patología Agroforestal, Departamento de Agronomia, Universidad de Córdoba, Campus deRabanales, Edif. C4, 14071-Córdoba, Spain.Verticillium wilt of olive (VWO), caused by Verticillium dahliae, is nowadaysthe most destructive olive disease in the Guadalquivir Valley in Andalucía. In lastyears, some growers are establishing a new olive intensive cultivation system, basedon high tree densities with 2000 tree/ha arranged in hedgerows. ‘Arbequina’ is thebetter-adapted olive cultivar to hedgerow system, but in some cases ‘Picual’ (majorSpanish cultivar) has been used. Both cultivars are highly susceptible to theDefoliating pathotype of the pathogen in controlled conditions, although ‘Arbequina’seems to be less susceptible than ‘Picual’ under field conditions. In this work, severalagronomical and phytopathological parameters has been studied in six hedgerow oliveorchards affected by VWO planted with ‘Arbequina’ (5 fields) or ‘Picual’ (1 field). Ineach field, inoculum density of V. dahliae in soil was determined before orchardestablishment by wet sieving method. Thereafter, fields were inspected, from 14 to 64months after planting, and disease incidence scored in two separate subplots (5 rows,100 trees/row) of each field. Inoculum density in field soils before planting rangedfrom