Sudden Oak Death

Phytophthora ramorum

Pest and disease search

Sudden Oak Death is the common name of a disease caused by the plant pathogen Phytophthora ramorum. The disease kills oak and other species of tree and has had devastating effects on the oak populations in California and Oregon, as well as being present in Europe. Mortality has also been reported in arbutus, beech, rhododendron, Vaccinium and Viburnum. These plants and others may also exhibit symptoms such as dieback, wilting, and lesions and may play an important role in the spread of the pathogen, both by natural movement in the environment and by the movement of infected plant material via the nursery trade.

Background

Symptoms of Phytophthora ramorum include bleeding cankers on the trunk and dieback of the foliage, sometimes leading to the death of the tree. Phytophthora ramorum also infects a great number of other plant species, such as rhododendrons, causing a non-fatal foliage disease known as ramorum dieback. Such plants can act as a source of the inoculum for the disease, with the pathogen producing spores that can be transmitted by wind and water.

Phytophthora ramorum was first reported in 1995, and the origins of the pathogen are still unclear. Very little control mechanisms exist for the disease, and they rely upon early detection and proper disposal of infected plant material.

Import Requirements

Phytophthora ramorum is considered a regulated disease for imports of nursery stock. Import health standards contain measures to prevent the introduction of exotic diseases into New Zealand. The following is a summary of New Zealand's current import requirements for the main classes of Phytophthora ramorum host material:

Nursery Stock

The import health standard has specific measures in place for host material of Phytophthora ramorum; these can be found in section 2.2.1.10:

• 155.02.06: Importation of Nursery Stock

Hosts of Phytophthora ramorum are only permitted to be imported from countries recognised by New Zealand as Approved Pest Free Areas, such as Australia, Israel and South Africa. Imports of host material from other countries may only occur if they have MAF approved Pest Free Place of Production programs for Phytophthora ramorum, currently there are no MAF approved Pest Free Place of Production for Phytophthora ramorum.

See importing nursery stock for additional information.

Approved Pest Free Areas for Phytophthora ramorum

The following countries or regions are currently considered MAF approved free areas for the Sudden Oak Death disease or the causative fungus Phytophthora ramorum (updated 27 August 2004):

The following countries or regions are considered by MAFBNZ to be infested or potentially infested by the Sudden Oak Death disease or the causative fungus Phytophthora ramorum (updated 27 August 2004):

¹ Review of Host Status of Rosa species for Phytophthora ramorum (48 KB) (2 December 2004)

Page last updated: 29 July 2010