Characterization and pathogenicity of Cylindrocarpon-like asexual morphs associated with black foot disease in Algerian grapevine nurseries, with the description of Pleiocarpon algeriense sp. nov

During a survey of black foot disease in Algerian grapevine nurseries, a collection of 79 Cylindrocarpon -like isolates were obtained. Based on morphology and DNA sequence data of histone H3 ( his3 ), three species of Dactylonectria were identified including Dactylonectria torresensis (40 isolates), D. macrodidyma (24 isolates) and D. novozelandica (14 isolates). In addition, one isolate belonging to the genus Pleiocarpon was found and it is described here as a new species, Pleiocarpon algeriense , based on morphological features and DNA sequence data of the internal transcribed spacer region (ITS), translation elongation factor 1-alpha ( tef1 ), β-tubulin ( tub2 ), large subunit nrDNA (LSU) and histone H3 ( his3 ). This is the first time that these species are reported in Algeria. Pathogenicity tests, were conducted with representative isolates from each species. All of them were able to induce typical necrosis symptoms on grapevine cuttings. These results emphasize the urgent need to implement an integrated management strategy for black foot disease in Algerian grapevine nurseries in order to reduce the incidence of this disease on grapevine planting material and to prevent that it spreads to new grapevine production areas.