Prevalence and distribution of Botryosphaeriaceae species in New Zealand grapevine nurseries

To determine presence of infection by botryosphaeriaceous fungi in plant materials from different grapevine nurseries, different types of grafted plants and cuttings were requested from nine grapevine nurseries around New Zealand. Of the 311 propagation materials and plants collected, 23 % were infected by botryosphaeriaceous fungi. The highest incidence was in failed grafted plants (33 %), followed by Grade 1 plants (28 %), rootstock cuttings (19 %), scion cuttings (17 %) and Grade 2 plants (7 %). For grafted plants, most isolates (80 %) were from near the graft unions while infections on rootstocks and scion cuttings were mostly from the middle (39 %) and basal parts (46 %). Identification of isolates by morphological and molecular methods showed that seven species were present in nurseries, being Neofusicoccum luteum (57 %), N. parvum (18 %), N. australe (8 %), Diplodia mutila (8 %), Botryosphaeria dothidea (5 %) and D. seriata (3 %), with one novel isolate of N. macroclavatum. These results show that Botryosphaeriaceae species were present in propagation materials and in the grafted plants supplied by nurseries, indicating that some of the current vineyard infections may have originated in the propagation nurseries.