Incidence and distribution of botryosphaeriaceous species in New Zealand vineyards

The aim of this study was to determine the identification, incidence and distribution of botryosphaeriaceous species in New Zealand vineyards. A field study of 43 vineyards across six wine growing regions was conducted. A total of 336 isolates of botryosphaeriaceous species were isolated from 238 diseased grapevine samples. Morphological identification and phylogenetic analysis of the ribosomal RNA gene region, partial sequence of the translation elongation factor 1-alpha gene (EF1-α) and the β-tubulin gene identified nine botryosphaeriaceous species: N. parvum, N. luteum, N. australe, N. ribis, D. mutila, D. seriata, B. dothidea, Do. iberica and Do. sarmentorum. These species have been reported in other grape growing regions worldwide. Eighty eight percent of vineyards and 68% of symptomatic vines sampled were positive for botryosphaeriaceous species. Incidence and distribution of the botryosphaeriaceous species populations varied between the North and South Islands with N. parvum being the predominant species. The variability in incidence and distribution of the botryosphaeriaceous species may be influenced by climatic conditions and different sources of inoculum in the regions sampled. The results of this research clearly identified botryosphaeriaceous species as the target pathogens for development of management strategies for grapevine decline in New Zealand.