First detection of stolbur phytoplasma in grapevines (Vitis vinifera, cv Chardonnay) affected with grapevine yellows in the Ukraine

During summer 2003, symptoms typical of a grapevine yellows (GY) disease were seen in grapevine plots planted in 2000 with cv Chardonnay in the Ovidiopolskij region (Odessa area) of the Ukraine (Fig. 1). Ten to 20 % of the vines showed typical GY symptoms i.e. rolling and discolouration of leaves and uneven lignification of shoots. Important GYs in Europe are Flavescence dorée (FD) and Bois noir (BN). FD, transmitted by the vine leafhopper Scaphoideus titanus, is a quarantine disease in the EU and Ukraine, and is epidemic in certain areas of France, Italy and Spain. BN is found in Asia Minor and is associated with the endemic stolbur phytoplasma and transmitted by a polyphagous planthopper, Hyalesthes obsoletus.

DNA extracted from leaf samples taken from 5 diseased grapevines was tested by PCR using standard generic primers (P1/P7 and R16F2n/R16R2) that amplify phytoplasma rDNA. Positive amplification was obtained from all 5 samples (not shown). Cuttings were taken in December 2003 of lignified canes from 15 grapevines that had shown symptoms during the summer. DNA extracted from phloem scrapings was amplified using a bi-specific PCR procedure for the detection of FD and BN phytoplasmas (Clair et al., 2003). Seven cuttings out of the 15 tested were positive for a stolbur phytoplasma (Fig. 2). The other 8 cuttings tested negative, as did the healthy grapevine control.

Earlier reports have described the presence of GY symptoms on cv Regina in Romania (Rafaila & Costache, 1968) and on cv Chardonnay in Moldavia (Marinesku et al., 1990). At that time the phytoplasma associated with this disease could not be detected in grapevine and the etiology and vector of BN were unknown, although H. obsoletus had been described in the South of Ukraine (Zirka, 1967). Since no direct control methods are available for BN, affected plants will be mapped over the next years to check for recovery. Further surveys will include monitoring of GYs, to confirm the role of H. obsoletus and to screen for S. titanus, a harmful pest actively spreading in Europe. This is the first record of stolbur phytoplasma infecting grapevines in the Ukraine.