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Riedle-Bauer M.,Hohere Bundeslehranstalt und Bundesamt fur Wein und Obstbau Klosterneuburg | Hanak K.,Hohere Bundeslehranstalt und Bundesamt fur Wein und Obstbau Klosterneuburg | Regner F.,Hohere Bundeslehranstalt und Bundesamt fur Wein und Obstbau Klosterneuburg | Tiefenbrunner W.,Bundesamt fur Weinbau
Journal of Phytopathology | Year: 2010

In recent years, visual and analytical observations revealed a significant increase of 'Bois noir' (BN) in Austrian vineyards. Removing infected parts by pruning can prevent or reduce spread of the pathogen within the vines. Knowledge about the effect of pruning practices on recovery rates is essential for grapevine growers. Vines showing BN for the first time were visually categorized into classes of symptoms according to disease severity. In the ensuing winter, plants were pollarded 15 cm above the graft union (511 vines), cane pruned (529 vines) or spur pruned (heavy pruning of canes leaving spurs only; 31 vines). Pollarding resulted in significantly higher recovery rates (yearly average 62-84%) in the next growing season and significantly lower recurrence rates in the following years than cane pruning (yearly average 29-49% in the next growing season). Spur pruning was statistically indistinguishable from cane pruning. Our data allowed the conclusion that extensive removal of infected wood is crucial for immediate and persistent success of pruning measures. Recovery was significantly influenced by the severity of BN, by the cultivar and by the observation year. With pollarding treatments, a significant correlation between recovery and plant age was noticed. © 2010 Blackwell Verlag GmbH.

Aryan A.,AIT Austrian Institute of Technology | Brader G.,AIT Austrian Institute of Technology | Mortel J.,Hohere Bundeslehranstalt und Bundesamt fur Wein und Obstbau Klosterneuburg | Pastar M.,AIT Austrian Institute of Technology | Riedle-Bauer M.,Hohere Bundeslehranstalt und Bundesamt fur Wein und Obstbau Klosterneuburg
European Journal of Plant Pathology | Year: 2014

Bois noir (BN) associated with 'Candidatus Phytoplasma solani' (Stolbur) is regularly found in Austrian vine growing regions. Investigations between 2003 and 2008 indicated sporadic presence of the confirmed disease vector Hyalesthes obsoletus and frequent infections of bindweed and grapevine. Infections of nettles were rare. In contrast present investigations revealed a mass occurrence of H. obsoletus almost exclusively on stinging nettle. The high population densities of H. obsoletus on Urtica dioica were accompanied by frequent occurrence of 'Ca. P. solani' in nettles and planthoppers. Sequence analysis of the molecular markers secY, stamp, tuf and vmp1 of stolbur revealed a single genotype named CPsM4_At1 in stinging nettles and more than 64 and 90 % abundance in grapevine and H. obsoletus, respectively. Interestingly, this genotype showed tuf b type restriction pattern previously attributed to bindweed associated 'Ca. P. solani' strains, but a different sequence assigned as tuf b2 compared to reference tuf b strains. All other marker genes of CPsM4_At1 clustered with tuf a and nettle derived genotypes verifying distinct nettle phytoplasma genotypes. Transmission experiments with H. obsoletus and Anaceratagallia ribauti resulted in successful transmission of five different strains including the major genotype to Catharanthus roseus and in transmission of the major genotype to U. dioica. Altogether, five nettle and nine bindweed associated genotypes were described. Bindweed types were verified in 34 % of grapevine samples, in few positive Reptalus panzeri, rarely in bindweeds and occasionally in Catharanthus roseus infected by H. obsoletus or A. ribauti. 'Candidatus Phytoplasma convolvuli'(bindweed yellows) was ascertained in nettle and bindweed samples. © 2014 The Author(s).

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