MLO-INFECTED WEEDS IN THE VINEYARDS OF NORTH-WESTERN ITALY

Ten species of herbaceous plants and shrubs with MLO symptoms such as stunting, bushing, yellowing, reddening, virescence or phyllody were c ollected in both grapevine yellows (GY)-infected and uninfected vineya rds. By electron microscopy, MLOs were found in the sieve tubes of eig ht species. The presence of MLOs in Picris echioides is demonstrated f or the first time. The possible role of MLO-infected weeds in the spre ad of GY disease is discussed.