Zespri’s Shane Max recently gave an update on international Psa-V progression and how their offshore growers were faring as they are now well into the spring growing season.
A short, seven-minute video presentation with updates from Japan, Korea, France and Italy can be viewed here.
The video concludes with some important take-home messages for New Zealand growers.
Lara Harrison, KVH Communications
While Psa-V progression has slowed during the 2014-15 growing season in most regions, its important growers don’t become complacent with their Psa-V management, particularly as we head into winter.
A better understanding of managing the disease, combined with a fairly warm, dry growing season has resulted in a significant drop in Psa-V levels on most orchards.
However some orchards, particularly those in challenged locations, still have significant Psa-V pressure impacting on yields and orchard profitability. The photo above shows cane dieback and fruit shrivel on a Gold3 orchard in a challenged Waihi site.
This is a reminder that disease levels could quickly increase in any orchard as the weather becomes cooler and wetter, and if Psa-V is not proactively managed.
Immediately after harvest apply copper to protect fruit stalks. Using summer rates of copper will minimise leaf damage and is recommended if copper is being combined with Actigard™ as leaves need to be actively photosynthesising for Actigard™ to be properly absorbed. Where maintenance of leaf condition is less critical apply copper at winter rates. Do not apply Actigard™ to stressed vines.
All growers should be maintaining protective spray programmes in the lead up to winter and ensuring best-practice hygiene is carried out through the remainder of harvest and pruning. This will provide the best possible start for orchards next spring.
Peter Mourits, KVH Operations
As harvest progresses and resources become stretched, growers and harvest contractors are reminded of the importance of ensuring orchard hygiene standards are maintained. KVH has received calls from growers concerned that they are seeing standards start to slip.
The recent find of a streptomycin resistant strain of Psa-V, identified through the industry resistance testing programme, is a strong reminder of how new threats can arise and growers must stay on their guard to reduce risk of spread of disease.
Clean down areas with suitable sanitisers, and check to ensure no plant material is moved on or off the orchard through people or machinery remain important strategies in protecting orchards from incursions in all regions.
Linda Peacock, KVH Operations
KVH has recently received a Plant and Food Research report about the trial of manufacturing compost using reject kiwifruit (and associated debris) mixed with wood pulp.
The report found the compost tested ‘not-detected’ for Psa-V and that kiwifruit seed was destroyed during the composting process.
The Kawerau-based manufacturer is seeking to ramp up production of compost using reject kiwifruit, and to sell the product to primary producers, including kiwifruit orchardists, in the Bay of Plenty.
KVH has amended its protocols around movement of compost containing kiwifruit material so an approval can be given to compost manufacturers on a case by case basis, as long as the product meets criteria including Psa-V not-detected and kiwifruit seed destruction.
KVH and the Bay of Plenty Regional Council have been supportive of this research as increasing quantities of reject fruit for composting will likely reduce the amount of fruit available to birds resulting in further wild kiwifruit populations. There is thought to be about 60,000 tonnes of reject fruit produced from Bay of Plenty post-harvest companies.
KVH has received numerous enquiries from compost suppliers in the last month. KVH is continuing to work with Zespri’s OPC to develop a KiwiTech Bulletin providing guidance around suitable compost compositions and distribution protocols.
John Mather, KVH Biosecurity
Click here to view the full schedule of the FON June field days.
Last week the Ministry for Primary Industries (MPI) launched ‘Biosecurity 2025’ – a project to review and future-proof New Zealand’s biosecurity system and replace the current 2003 New Zealand Biosecurity Strategy.
MPI will be seeking feedback from biosecurity stakeholders, Māori and the public through a consultation process. To register your interest email firstname.lastname@example.org
KVH Chief Executive Barry O’Neil says: “we look forward to being actively involved in this project with MPI and engaging with industry to ensure the best possible outcome for the kiwifruit industry is achieved. The recent Queensland fruit fly response highlights the critical importance of an effective biosecurity system so this is an excellent opportunity for our industry to contribute to the new Directional Document which will shape New Zealand’s future biosecurity system.”
Lara Harrison, KVH Communications
Waimea Nurseries in Nelson has become the latest nursery to join the Kiwifruit Plant Certification Scheme (KPCS) and is now selling KPCS certified kiwifruit plants.
Purchasing certified kiwifruit plants mean growers have assurance they are investing in the best start for their plants.
To date, four nurseries located in Kerikeri, Gisborne, Motueka and Nelson, have joined the KPCS. These nurseries are identified on the KVH nursery list here.
Other nurseries have expressed strong interest in joining the scheme and are currently documenting how their operation addresses biosecurity risks, as required under the KPCS.
All nurseries selling and dispatching kiwifruit plants must be registered with KVH or be part of the KPCS.
From 1 October 2016, all kiwifruit plants for sale and distribution must be KPCS certified.
For more information, visit www.kvh.org.nz/kpcs.
Karyn Lowry, KVH Operations
This bi-monthly report provides information about the progress over February and March 2015 for the Psa R&D programme. The following projects are summarised in the report:
Click here to read the report.
Lara Harrison, KVH Communications
MPI, KVH and P&FR have been an investigating a virus discovered in kiwifruit seed imported through Post Entry Quarantine (PEQ). There is little known about the virus although it is not associated with any specific symptoms to kiwifruit vines.
The investigation has found that this uncharacterised Betaflexiviridae virus was present on multiple seed imports dating back as far as 1996 but is not widespread across the industry and has a limited distribution, but greater than what can be feasibly eradicated. Despite not being linked to disease, KVH and P&FR are taking a conservative approach and working to limit the spread of the virus.
Matt Dyck, KVH Biosecurity
Results from KVH’s regular testing programme have showed Psa-V resistance from samples in two Te Puke orchards.
These finds were detected in the most recent round of an ongoing copper and streptomycin resistance monitoring programme that has been in place since 2011. The programme’s aim is to ensure resistance is detected early. These results are not completely unexpected.
The streptomycin resistant Psa-V is still susceptible to copper, meaning growers can still effectively control Psa-V.
Resistance to streptomycin can occur naturally, even on orchards where streptomycin has not been used. KVH and Zespri are working with relevant authorities to understand the implications of this result and other orchards in New Zealand could also have streptomycin resistance. There is no evidence to suggest the resistance has occurred due to inappropriate use of streptomycin.
Streptomycin use and resistance has previously been identified in other horticultural industries in NZ and successful management strategies have been developed to deal with this.
Streptomycin use not permitted at present
Industry use of streptomycin (registered and sold in NZ as KeyStrepto™) is not permitted at this time of year under Zespri’s Crop Protection Standard. KVH and Zespri are reviewing the kiwifruit industry use conditions of Streptomycin for the 2016 season and will notify the industry once this is confirmed in June.
Through the R&D and product testing programme Zespri and KVH are continuing to test and identify alternative and sustainable control approaches for Psa-V. Zespri has been developing options to reduce industry reliance on antibacterial products.
What is being done?
Both orchards have been working with KVH to ensure best practice resistance management is in place. This includes the application of copper spray, movement restrictions on plant material and a strong focus on orchard hygiene. Intensive sampling and testing of the two orchards and the surrounding orchards is underway. Further testing is also being carried out to establish the nature of resistance.
What can growers do?
KVH continues to recommend growers adhere to their orchard management plans, including a robust protective spray programme, orchard hygiene and the removal of infection from orchards as per KVH’s best practice advice through autumn. It is also very important to use protective spray products at label rates.
Refer to the KVH Seasonal Management Guide at www.kvh.org.nz/seasonal_advice.
Kiwifruit growers who believe spraying is providing no control, and suspect resistance, should contact KVH on 0800 665 825 or email email@example.com. KVH will then assess the situation and carry out additional testing for resistance as required.
What is streptomycin?
Streptomycin is an antibacterial product and has been registered for use against Psa-V in New Zealand since 2011.
Antibacterial products are registered for use in Canada, United States, New Zealand and a number of Asian countries against a range of bacterial diseases in horticulture, including fire blight in apples and pears.
It is registered in New Zealand for use on apples, tomatoes, stonefruit and kiwifruit.
Why is it used in the NZ kiwifruit industry?
MPI granted a Limited Label Claim with strict use conditions for streptomycin for the control of Psa-V on kiwifruit vines.
Antibacterials are considered to be one of the most effective tools for managing Psa-V infection. For information on efficacy refer to: www.kvh.org.nz/product_testing_results.
How has resistance developed?
We are still investigating the exact nature of the resistance but this can occur naturally as a result of other bacteria “sharing” their DNA.
Bacteria can also sometimes change genetically to resist protective products, meaning they are no longer effective against Psa-V. For more information refer to Plant & Food Research scientist Joel Vaneste’s technical presentation on KeyStrepto™ use and resistance on YouTube (link here).
Overseas experience has seen resistance develop in Pseudomonas sp. against both copper and antibacterials. Ceasing use of the product for a period of time is the key way of overcoming resistance.
Why did the NZ kiwifruit industry introduce streptomycin to the CPS if resistance has developed with its use in other industries?
When Psa-V was discovered in NZ, antibacterials were considered a necessary tool to help control Psa-V and allow commercial production to continue. Advice was provided to growers to limit the development of resistance through alternating protectant products, using recommended label rates, ensuring good spray coverage and maintaining orchard hygiene and removing infected material from orchards.
Will KeyStrepto™ be removed from the Zespri CPS?
KVH and Zespri are reviewing the ongoing kiwifruit industry use conditions of KeyStrepto™ in the Zespri Crop Protection Standard and industry will be advised once confirmed. We expect this decision to be made in June.
Is there another antibacterial growers could use instead?
Zespri is also reviewing the data on another antibacterial product Kasumin (active ingredient kasugamycin) to determine if it will be included in the 2016 Crop Protection Standard. This decision will be communicated to industry in June as well.
Can growers still use streptomycin?
Industry use of streptomycin is currently prohibited under Zespri’s Crop Protection Standard until its use conditions have been confirmed.
Zespri does not allow applications of KeyStrepto to fruit and has a zero-antibiotic residue policy underpinned by a 100 percent residue-testing programme of all orchards for antibacterial residues. All orchards are also subject to a multi-residue test, which tests for 300 active compounds. In the four years this testing programme has been in place, no antibacterial residues have been detected in crops.
What commitment is there to finding sustainable ways to manage Psa-V?
To date, more than $12m has been spent on a global research and development programme for Psa-V since it was detected in 2010; and a further $2m per year is committed to R&D into the future.
The R&D programme includes a product testing programme developed to identify, rigorously test and get permission to use suitable products to help manage and control the spread of Psa-V. To date, more than 300 products have been tested for efficacy against Psa-V in the KVH/Zespri product testing programme.
One of the challenges with BMSB is the lack of effective tools available to detect and control this organism. In comparison the tools available for fruit fly are far more advanced as research has been ongoing for a much longer period of time.
Last year in response to the emerging threat of BMSB, MPI and other GIA signatories developed a research plan to provide more tools in the battle against BMSB. The three themes where the research is directed are:
Many of the research projects have been granted urgent priority status and link in to existing projects in the USA to deliver results as quickly as possible. Some projects have delivered results already. However, for others results will still be years away given the nature of the work.
In addition to this wider coordinated research approach, the kiwifruit industry is also undertaking research specific to our industry.
The impacts of BMSB on kiwifruit are unknown as there are few instances where invading BMSB populations overlap with kiwifruit production areas.
KVH has initiated discussions with Californian researchers to establish trials that will determine the impacts of BMSB on kiwifruit in both the laboratory and outdoor planted areas.
Matt Dyck, KVH Biosecurity