Biosecurity research projects and reports

This page lists recently published biosecurity research and reports.

KVH and Zespri have initiated a large research programme looking to better understand Kiwifruit Trunk Diseases (KTDs) in New Zealand kiwifruit.

While relatively early on in our research programme, it is becoming clear that no single pathogen is responsible for KTDs but rather it is a complex of fungal pathogens that are associated with these vine decline symptoms in kiwifruit. One of the groups of organisms that appears to be involved are a fungal group called the Ilyonectria species group. Species of Ilyonectria cause root rots of a wide range of plants including kiwifruit. In other countries infection of kiwifruit by these pathogens causes leaf wilting, black and necrotic lesions on woody tissues of both the rootstock and roots, and death of the trees.

Prior to this research, we did not know much about Ilyonectria and its presence in kiwifruit. This project aimed to clarify the species of Ilyonectria associated with kiwifruit in New Zealand and establish whether they were pathogenic (disease causing). We discovered four species within the Ilyonectria group in New Zealand but we did not understand if they were causing disease, or simply secondary invaders. As such, we set out to understand the pathogenicity of these four species that make up this complex. From this report, we now understand that these species are capable of causing disease in inoculated roots which suggests that they are pathogenic to kiwifruit. Further work on these species in whole plants would aid in confirming their association with the disease symptoms we are seeing from diseased vines.

Read the report here.

It was acknowledged there is little information known on the ability of pollen that transmit pathogens. To address this gap, an extensive literature review was undertaken on pollen and associated floral debris as a means of pathogen (viruses, oomycetes, fungi and bacteria) spread. This work will help inform KVH’s proposed Pathway Management Plan to ensure appropriate measures are implemented to manage the level of risk associated with pollen.  Key findings from the report include:

- That pollen is a substrate that can transmit pathogens, but there a few pathogens present in NZ that are known to be pollen transmissible and;
- The pollen review confirms that the existing pollen protocols are adequate for managing current known risks.

Read the report here or view a summary presentation here.

This project aimed to understand which members of the fungal group Nectriaceae are associated with kiwifruit trunk disease. A survey of three kiwifruit orchards (two in the Bay of Plenty, one in Motueka), with a history of disease, took place in early 2019. In each orchard, fungal isolations were made from bark at the crown and from woody trunk cores taken from symptomatic and asymptomatic vines. This report is the first objective of a larger piece of work.

Read the report here or view a summary presentation, including management advice here.

This literature review used Chinese and English databases in order to pull out publications about YSSB and kiwifruit. The report describes the lifecycle of YSSB, its impacts on kiwifruit and other crops, and potential control options.

Read the report here.

The taxonomy of Psa has been evolving rapidly in recent years. This report reviews the nomenclature associated with Psa and the virulence of the different biovars of Psa.  It outlines the phylogenetic relationship of the five biovars, before reviewing the evolution of the Psa taxonomy. The ability of a few strains of different biovars to multiply on or in kiwifruit tissues has been reported but as of today there is no study which demonstrates that strains of some biovars are more virulent than strains of others.

Read the report here.

Xylella fastidiosa, a deadly bacterial pathogen, is currently having devastating impact across horticultural industries in both Europe and the USA. This pathogen can infect many different plants, both natives and important crops, but we did not know the full scale of potential damage if it got into New Zealand. The Xylella Action Group (XAG) of which KVH is a member, was assembled with the purpose to collaborate and improve New Zealand’s readiness should Xylella fastidiosa be detected on our shores.

Through the Zespri Innovation funding we contributed, alongside other potentially impacted industries and stakeholders, towards a literature review to better understand the impacts of an incursion to New Zealand. While the report highlighted that Xylella fastidiosa has an incredibly wide host range comprising more than 350 species, the good news is that there are no reports of it affecting kiwifruit. However, there is still much uncertainty, particularly around our vector status, and thus our future potential host status.

Read the report here.

SLF is native to Asia and has recently spread to the United States causing damage to a number of valued crop and tree species. SLF has not established in New Zealand but is considered a significant biosecurity threat to valued crop species including kiwifruit. English sourced references about SLF damage to kiwifruit are very sparse, likely due to only recently being invasive outside of its native range. This report provides a collation of the translation of six Chinese publications on the SLF on kiwifruit in China. It highlights the impacts of SLF on kiwifruit and control methods they use to manage it on-orchard.

Read the report here.

A literature review presenting detailed information on the potential threat posed by Phytophthora species to kiwifruit production in New Zealand. As well as providing an overview of Phytophthora in kiwifruit, a further three case studies on well-studied horticultural crops help to highlight the general principles of spread, management and control of Phytophthora.

Read the report here.

This review looked at the biology, distribution, impacts and management of White Peach Scale. It also provided information of potential control options for kiwifruit growers in New Zealand.

Read the report here.

This review looked at the biology, distribution, impacts and management of Spotted Lanternfly. It also provided information of potential control options for kiwifruit growers in New Zealand.

Read the report here.

This review looked at the biology, distribution, impacts and management of South American fruit fly. It also provided information of potential control options for kiwifruit growers in New Zealand.

Read the report here.

This review looked at the biology, distribution, impacts and management of BMSB. It also provided information of potential control options for kiwifruit growers in New Zealand.

Read the report here.

This review looked at the biology, distribution, impacts and management of fruit piercing moth. It also provided information of potential control options for kiwifruit growers in New Zealand.

Read the report here.