Temporal shifts of Bois Noir phytoplasma types infecting grapevine in South Tyrol (Northern Italy)

Abstract

Results and Discussion: Two different restriction enzyme profiles of the Bois noir (BN) phytoplasma, corresponding to VK-Type I and VK-Type II (LANGER and MAIXNER 2004), were found in South Tyrol (Table). Both these BN-types were previously detected in German viticultural areas affected by grapevine yellows. While in Germany also a third BN-type was described (VK-Type III), which is exclusively restricted to the Mosel valley, this strain was not found in South Tyrol. Each BN-type has been associated with a different herbaceous host plant species of the vectoring insect H. obsoletus: VK-Type I with Urtica dioica, VK-Type II with Convolvulus arvensis, and VK-Type III with Calystegia sepium (LANGER and MAIXNER 2004). Consequently, it