On the possible relationship between Kober stem grooving and grapevine virus A

Investigations were carried out to establish possible correlations of two diseases of the rugose wood complex, i.e. Rupestris stem pitting (RSP) and Kober stem grooving (KSG) with grapevine virus A (GVA) and grapevine leafroll associated viruses I (GLRaV I) and III (GLRaV III). To this purpose 84 clonal accessions of different wine grape cultivars were analyzed by ELISA and by indexing onto the indicators Vitis rupestris, Kober 5BB and LN 33. The results obtained clearly indicated that none of the viruses taken into consideration is apparently involved in the etiology of RSP. Conversely, a remarkably close association of GVA with KSG was discovered

New findings on phytoplasmas-affected Auchenorrhyncha populations in Sardinian vineyards

Epidemiological research was carried out in two vineyards affected by "Bois noir" (BN). Auchenorrhyncha potential vectors of BN, were monitored periodically between May to November 2004 in a vineyard and between May to June 2005 in the other. Auchenorrhyncha samples were tested to assess phytoplasmas presence using PCR and RFLP. Euscelis lineolatus was positive to 16SrI-C ("Clover phyllody" reference strain) in 2004 while, in 2005, at the preimaginal age, at the 16SrXII-A ("Stolbur" reference strain) phytoplasmas. Exitianus taeniaticeps acquired 16SrI-B ("Maryland aster yellow" reference strain), 16SrV-A ("Elm yellow" reference strain) and 16SrX-C ("Pear decline" reference strain) phytoplasmas in 2004. Resulted news host of phytoplasmas: Psammotettix alienus was positive to 16SrI-B, 16SrV-A, 16SrX-A phytoplasmas ("Apple proliferation" reference strain) in 2004 and to 16SrXII-A in 2005. E. lineolatus and P. alienus for 16SrXII-A E. taeniaticeps for 16SrV-A 16SrX-C and P. alienus for 16SrV-A and 16SrX-A Researches on the effective epidemiological role of E. lineolatus and P. alienus in BN are in progress. \ua92006 IEEE