Scientific opinion on the pest categorisation of Verticillium dahliae Kleb

The European Commission requested the EFSA Panel on Plant Health to perform a pest categorisation of Verticillium dahliae Kleb., the fungal pathogen responsible for many Verticillium wilt diseases. V. dahliae is a single taxonomic entity, and sensitive and reliable methods exist for its detection and identification. V. dahliae is a highly polyphagous pathogen, affecting, overall, 400 cultivated and non-cultivated plant species. It is a host-adapted rather than a host-specific pathogen and has the ability to continuously widen its host range and develop races/pathotypes that can overcome host resistance or be more virulent on known hosts and host cultivars. V. dahliae is a vascular pathogen that causes wilt and plant death, thus impairing the growth and shortening the lifespan of its hosts. The pathogen is currently present in most parts of the risk assessment area, where yield reductions up to 50 % or more have been reported on some high value crops, including cotton, olive, potato, strawberry and ornamentals. There are no obvious eco-climatic factors limiting its potential establishment and spread in the non-infested part of the risk assessment area, where hosts are present. Once established, the pathogen can spread by both natural and human-assisted means. Movement of infected host plants for planting, especially asymptomatic plants, and seeds can introduce the pathogen (and its highly virulent races/pathotypes) into new areas. Application of integrated management strategies combined with disease risk assessment (assessment of the available soil-borne inoculum, determination of races/pathotypes present in the site, field cropping history) may reduce the impacts of Verticillium wilt in the risk assessment area, but it cannot eliminate the pathogen. V. dahliae is listed in Annex IIAII of Directive 2000/29/EC and, despite its wide host range, it is regulated only on Humulus lupulus (hop), for which the pathogen is considered of minor importance compared to V. nonalfalfae. (C) European Food Safety Authority, 2014