Winter is an opportune time for growers to remove visible signs of infection from their orchards, including cane dieback and exudate. Ideally, growers should do this before winter pruning. Cut back 40cm from signs of infection.

Removing infection allows pruners to structure vines accordingly and minimise later potential impacts on production.

Click here to read more about winter protection from Psa-V.
 

Growers in the process of removing Hort16A should ensure canopies are well protected with copper sprays to minimise the chances of infection and Psa-V spread.  Ideally, remove any Psa-V infected material and dispose of it by on-site burial or burning. If removed canopy is remaining within the block, fine mulching and use of digesters to speed break-down of is highly recommended.

Psa-V can survive for at least 15 weeks on the orchard floor in prunings and infected plant debris, presenting an ongoing Psa-V risk. Removal of this material will benefit new grafts next spring.

This recommendation also applies to any canopies where infection may be present.
 

A reminder to all when travelling overseas: be vigilant with biosecurity measures particularly if you have been visiting kiwifruit orchards. Shoes must be free of soil material and clothes worn in an orchard environment must be washed before entering New Zealand orchards.

On arrival into New Zealand it is important you declare any visits to foreign orchards to MPI Border staff so they can ensure all necessary measures are taken to prevent the accidental introduction of unwanted pathogens that could be devastating to our industry (such as Ceratocystis fimbriata).

Right: The KVH Psa-V Risk Model forecasts further heavy rainfall in Opotiki

Continuing wet periods across the country are keeping Psa-V risk elevated. Growers should avoid pruning in wet conditions or when rain is imminent. Ensure all pruning cuts are protected prior to the next rainfall event and tools are sanitised between vines. Pruning staff should be asked to report signs of new Psa-V infection. Monitoring of males, especially in high risk blocks should be undertaken.

Consult the KVH Seasonal Management Guide—Autumn/Winter for best practice information and guidance. Growers unable to access their orchards because of wet ground conditions may consider aerial applications of copper. Address areas where soil drainage is an issue. Stressed vines are likely to be more susceptible to Psa-V.

KVH has developed a short one-page summary of key messages for orchard best practice during winter. This summary was distributed to attendees at the recent FON winter field days and is a useful tool to print out and place in staff areas and/or circulate to supervisors and orchard staff.

• Click here for a copy of the handout. 

Traceability of plant material, whether it is budwood, nursery rootstock or pollen, is fundamental to a successful biosecurity response. It is only by having a complete and comprehensive database of ALL people that move plant material can effective traceability occur.

Budwood suppliers are reminded they must register with KVH annually, before their first budwood collection for the year, including male budwood. Registration is a quick and simple process. Please do your part to help the kiwifruit industry become better prepared for future biosecurity incursions by registering with KVH.

• Click here to register via the KVH website, or call KVH on 0800 665 825.

Ceratocystis fimbriata is a fungal pathogen causing widespread damage to the Brazilian kiwifruit industry (see KVH Bulletin, 20 Feb). The disease is of significant concern to the New Zealand kiwifruit industry and efforts are being made to increase our understanding of the disease—both to prevent it from entering our borders and to effectively manage it should it arrive.

Efforts that are being made to understand this pathogen include:

A full literature review on Ceratocystis fimbriata on kiwifruit and other crops by an international expert in this field. This report is due in early 2015 and will include;

• Impact of the disease on crop production;
• Taxonomy of Ceratocystis fimbriata complex which is complicated and has possibly been confused in some instances;
• How the pathogen has spread and control measures that have been effective on other crops (there are no controls reported to be effective on kiwifruit);
• Evaluation of Ceratocystis wilt in kiwifruit in Brazil and potential for disease impact if strains aggressive to kiwifruit were introduced to New Zealand.
• Measures that should be deployed to reduce the risk of introductions of new strains of C. fimbriata to New Zealand and what could be done to minimise losses if a virulent strain was introduced.

Another research project being developed will use molecular techniques to determine the similarity of the Brazilian kiwifruit strain with the strain found in New Zealand kumara. This project would identify any underlying basis for differences in pathogenicity between the strains and would result in a DNA based detection test.

• Click here to view the investigation report following KVH and Zespri visit to infected orchards in Southern Brazil.
• Click here to view the KVH fact sheet on Ceratocystis fimbriata.

As advised in the KVH Bulletin (5 June) Psa-V was recently identified in Japan. To date, the disease has been identified in six Japanese prefectures: Ehime, Fukuoka, Saga, Okayama, Wakayama and Shizuoka.

This week officials from Japan’s Ministry of Agriculture, Forestry and Fisheries (MAFF) visited KVH and Zespri to learn more about how to best manage the disease. The Japanese visit to KVH included an update on Psa-V in New Zealand; best practice orchard management; an overview of the NPMP; movement controls; the Kiwifruit Plant Certification Scheme; and communications to industry and growers.

Around one percent of the total kiwifruit acreage in the infected areas has been affected by Psa-V in Japan. Control measures include cutting out and disposing of infected material and proactive spray control.

A second Japanese MAFF visit also occurred during the week in Wellington with MPI to discuss future export conditions of New Zealand pollen and budwood.
 

It’s possible for Psa-V to change genetically in order to develop resistance to chemicals or compounds that are currently used by growers to manage the disease. In other words, they would no longer be effective against Psa-V.

As few products are currently known to have efficacy against Psa-V, the loss of one or more of these due to resistance would make Psa-V much more difficult to manage. This would be a significant issue for the kiwifruit industry.

To date, Psa-V resistance has not been identified in New Zealand kiwifruit. However, overseas experience has seen bacterial resistance develop against copper and antibiotics. It can happen as a result of products not being used properly, or being over-used.

Ongoing testing as part of the KVH/Zespri R&D programme is underway to identify early any strains of Psa-V showing potential resistance.

It’s essential the kiwifruit industry is aware of this potential issue, and carries out best-practice management to avoid resistance.

Preventing Psa-V developing compound resistance
Growers and the industry can help reduce the risk of Psa-V developing compound resistance by following these simple steps.

• Always read and follow label instructions, including the recommended label rates. Using products at lower rates can cause resistance to develop.
• Use a combination and/or alternate effective products. This avoids applying the same compound/chemical multiple times in a row—making resistance more difficult to develop.
• Reduce diseased material in the orchard by ongoing management and removal of infected material.
• Maintain best-practice orchard hygiene.

A coordinated approach incorporating the above strategies across the entire industry will reduce the risk of resistance developing.

Kiwifruit growers who believe spraying is providing no control, or suspect compound resistance on their orchard, should contact KVH on 0800 665 825 or email info@kvh.org.nz. 

KVH will then assess the situation and carry out additional testing for resistance as required.
 

Industry feedback from the KVH Communications Survey strongly suggested the search function on the KVH website, and in particular within the R&D section, needs improvement.

After investigating limited options it was decided implementing a dedicated ‘google custom search engine’ on the KVH website will be the most effective option. This option will effectively increase the ability of users to find KVH website content.

However, to use the google search to the best of its ability, and to avoid breaching Google’s Terms and Conditions, the ‘restricted’ documents on the website will need to be made available to all website users. Therefore:

• KVH plans to open the R&D section to all users so these documents will no longer be ‘restricted’.
• Other restricted documents, including Zespri variety information, monitoring results and variety-specific case studies, will be removed from the website and available on request.
• The KVH Psa-V Risk Model will remain a ‘restricted’ tool for New Zealand growers, and accessible to registered users only.

If growers have any concerns, please contact KVH on 0800 665 825 or info@kvh.org.nz.

Congratulations to Patrick Malley from Whangarei * who took out the 2014 BOP Young Grower of the Year title at an awards dinner in Mount Maunganui last night.

Patrick competed against four other young up-and-coming horticultural leaders for the title in a series of practical and theoretical activities during the day; and a speech competition and quiz during the evening gala dinner. KVH’s Chris Clement was runner up.

Minister for Primary Industries, Nathan Guy, was the Guest Speaker at the event attended by almost 200 industry supporters and presented Patrick with the award (pictured above).

Patrick will go on to represent the Bay of Plenty in the National competition against other regional winners for title of NZ Young Grower.

* Contestants from outside of the BOP can enter the competition if they do not have a competition in their own region.
 

This week Primary Industries Minister Nathan Guy announced 29 new biosecurity graduates will further strengthen New Zealand’s biosecurity system, and help safeguard New Zealand’s primary industries from pests and diseases. This includes 24 new quarantine inspectors and five new dog handlers to be based between Auckland, Wellington and Christchurch.

Click here to read The Minister’s media release.