Outbreaks of onion yellow dwarf virus (OYDV) on onion crops in Calabria (Southern Italy).

In 2003-2004, chlorotic stripes, yellowing and curling of the leaves were observed in several onion (Allium cepa L., cv Cipolla rossa di Tropea) cultivations of Calabria (Lamezia Terme and Ricadi). Diseased plants ranged from 20 to 100%, depending on the field inspected. Electron microscope observations of leaf-dip preparation showed the presence of potyvirus-like particles about 780 nm in length.