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.
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.
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.
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).
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;
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.