KVH operates an Unusual Symptom process where we encourage growers and members of the industry to report anything unexpected happening on-orchard. Early reporting gives us the best possible chance of successfully managing any biosecurity risk and thereby reducing impacts to growers and wider industry.

Earlier this year, an orchard was sampled that had pockets of vines showing symptoms of poor cane and canopy development, splitting, and cankering on the trunks and relatively poor root systems.

Multiple kiwifruit pathogens were identified from these samples, which is common in this process, as well as a new-to-New Zealand oomycete (fungus-like organism), Phytopythium helicoides.

As P. helicoides is a known pathogen to horticultural and ornamental plants from 20 families, as well as kiwifruit, the Ministry for Primary Industries (MPI) investigated to determine any biosecurity risk. While P. helicoides has not been previously detected in New Zealand, it is not necessarily a new arrival. In fact, our increased surveillance efforts and the recent advances in molecular diagnostics mean that we are often discovering organisms that we weren’t previously aware of in kiwifruit orchards.

KVH and Zespri Innovation recently commissioned a Phytophthora survey of kiwifruit orchards for this very reason, to build our baseline knowledge of pathogens that already exist within our industry orchards and ensure we take appropriate action for any future new detections. To support this investigation, samples collected from this research were able to be revisited and evidence was found to confirm that P. helicoides is not a new arrival, has been present in New Zealand since at least 2022 but probably much longer, and is present in multiple kiwifruit growing regions.

KVH has worked with growers where this organism has been detected to ensure appropriate on-orchard practices are in place to manage risk, and MPI have now closed the investigation confident that management of comparable diseases already present in New Zealand will likely be effective to also manage P. helicoides.

This case study serves as a reminder of the value of proactive research to build our baseline knowledge, growers reporting unusual symptoms, and all of us as an industry not being complacent in on-orchard biosecurity practices - as we never know where and when the next biosecurity threat will appear.