Viruses in sweetpotato.

Sweetpotato in the Mediterranean is mainly grown in Egypt, Spain, Portugal, and Israel. Yields vary from 34 tons/ha in Israel to 7.8 tons/ha in Portugal. As sweetpotatoes are vegetatively propagated, the differences in yields are probably due to the quality in the propagation material, mainly infection by various viruses. The main viruses affecting sweetpotato in Mediterranean countries are Sweet potato feathery mottle virus potyvirus, Sweet potato sunken vein virus (Sweet potato chlorotic stunt virus) crinivirus, and their combined infection, causing the sweetpotato disease. Eleven other viruses sporadically reported from Mediterranean countries are also reviewed, as well as possible methods for control.