Protecting grapevine health in New Zealand

Grapevine trunk diseases (GTDs) are caused by fungi that spread slowly through woody tissue, killing the vine over many years. They are a threat to vineyards globally. Understanding GTDs is complicated as there are many fungal species involved, in a variety of potential combinations, and these can differ between different growing regions. To manage the disease in New Zealand and understand how GTDs develop, it’s important to be able to identify pathogens and interpret geographical differences. Until now, the spectrum of fungi involved in GTDs in New Zealand has not been well defined. 

In this review, scientists at Plant & Food Research, University of California (Davis), Lincoln University and Manaaki Whenua Landcare Research, summarised information on the fungi that contribute to GTD and that have been found in New Zealand to date

These investigations have confirmed that some of the species known to cause some of our most prominent GTDs are, indeed, common in our vineyards (e.g. Eutypa lata), as well as revealed the surprising prevalence of others (e.g. Phaeomoniella chlamydospora). Several species have also been detected for the first time in New Zealand vineyards (e.g. Inonotus, Diatrype, Sporocadus and Phaeoacremonium species).

Knowing which fungi cause GTD in New Zealand will help us to better understand how disease develops and, ultimately, how to control it. Culture-dependent surveying, DNA sequencing, and online searches of the International Collection of Microorganisms from Plants has provided a comprehensive list of the GTD fungi in New Zealand vineyards. Identification of species within key taxonomic groups has been validated by applying new sequencing-based technologies. The resulting collection of DNA sequences provides a baseline of knowledge for applying new sequencing-based technologies to identify multiple GTD pathogens simultaneously. These techniques will accelerate understanding of the distribution and ecology of the fungal species that influence the health of our grapevines. 

Journal Reference: Mundy D, Brown A, Jacobo F, Tennakoon K, Woolley R, Vanga B, Tyson J, Johnston P, Ridgway H 2019 Pathogenic fungi isolated in association with grapevine trunk diseases in New Zealand. https://doi.org/10.1080/01140671.2020.1716813