Pathogenic fungi isolated in association with grapevine trunk diseases in New Zealand

Abstract

ABSTRACTGrapevine trunk diseases (GTDs), caused by a complex of fungi, are a global threat to vineyard longevity. Identifying the fungi in each growing region is crucial for interpreting symptoms and understanding disease progression. Despite considerable research, the spectrum of fungi involved in GTDs in New Zealand remains uncertain and species identities within key taxonomic groups require validation with molecular sequences. We provide a synopsis of fungi from known pathogenic GTD taxa that have been identified in culture-dependent studies in New Zealand, especially those accessible through culture collections such as the International Collection of Microorganisms from Plants (ICMP). Results from a 2007–2010 countrywide vineyard survey for GTD fungi are presented, plus new isolates and associated DNA sequences from a 2017 survey of Marlborough and Hawke’s Bay vineyards and from institutional microbial collections. These new records clarify that authentic Eutypa lata and Phaeomoniella chlamydospora fungi, which are widely studied GTD pathogens, are present and probably common in New Zealand. First records of Inonotus, Diatrype, Sporocadus and Phaeoacremonium species are presented from New Zealand vineyards. The DNA sequences presented from GTD pathogens will facilitate the use of molecular detection technologies for measuring pathogen distributions in New Zealand vineyards and for biosecurity detections.