Look and report
Psa of kiwifruit is a declared pest in WA
Psa (Pseudomonas syringae pv. actinidiae) is a disease of kiwifruit. It is a quarantine pest and not known to occur in WA and must be reported to the department if found or suspected to be present in WA.
About Psa of kiwifruit
Psa is a bacterial disease that affects kiwifruit and kiwiberry vines. It can spread rapidly through kiwifruit orchards. It carries no risk to humans.
- Dark spots with yellow haloes appear on the leaves of kiwifruit in spring.
Photo: Leaf spots with yellow haloes (©2018 Kiwifruit Vine Health, NZ)
Photo: Psa causes wilt, dieback and cane death in kiwifruit vines (©2018 Kiwifruit Vine Health, NZ)
- Multiple leaf spots may join together and make the leaves drop.
- Buds and flowers may rot.
- Symptoms on the vine include stem cracking, cankers, wilt, dieback and cane death.
- Orange and white bacterial ooze appears on the bark of twigs and trunks.
Photo: White bacterial ooze emerging out of a cut vine (©2018 Kiwifruit Vine Health, NZ )
Photo: Bacterial slime from an infected vine (©2018 Kiwifruit Vine Health, NZ)
Photo: Red/orange exudate is visible on diseased vines (©2018 Kiwifruit Vine Health, NZ)
- Vine susceptibility is directly influenced by kiwifruit varieties and environment conditions.
There are several strains of Psa that can cause disease on Kiwifruit depending on the susceptibility of different kiwifruit varieties and environmental conditions.
• The bacteria are spread from plant to plant by wind and rain in the spring.
• Hot dry weather greatly reduces the survival of Psa.
• Psa is also spread on infected plant material, in kiwifruit pollen, on tools such as secateurs, and on footwear and vehicles.
• Psa survives in fallen leaves and pruning debris, on the surface of kiwifruit leaves and stems and in flower and leaf buds.
Legal duty to report
Psa (Pseudomonas syringae pv. Actinidiae) Takikawa et al. 1989 Biovars 1, 2, 3 and 5 are absent from Western Australia and are quarantine pests. They are prohibited organisms under section 12 of the Biosecurity and Agriculture Management Act 2007.
This means that any person who finds or suspects the presents of Psa of kiwifruit must report it to the department.
WA’s freedom from Psa of kiwifruit is supported by general and specific surveillance, and specific import requirements to prevent its entry.