No known vector.

Method	Instructions	NAPIS Survey Method
Visual	Collect symptomatic plant tissue by visual survey.	3031 - General Visual Observation

See the CPHST pest datasheet for detailed survey instructions.

No specific signs are present.

Symptoms are similar in appearance in all known hosts. Above ground symptoms of infected trees include: foliage reddening or browning over all or most of the crown (Green et al., 2012), a progressive withering and defoliation, crown thinning, loss of radial growth, dieback, decay of main roots, and death of the tree, which remains standing or falls because of the wind. Trees may die rapidly. In this case, foliage changes from chlorotic (yellow) to red, or slowly, with chlorosis followed by progressive defoliation leading to tree death after several years (Filip and Rosso, 1999).

P. austrocedrae produces necrotic lesions that affect the entire thickness of the phloem, evidenced by discoloration of the tissue, and also induces superficial staining of the sapwood (Greslebin et al., 2007; Greslebin and Hansen, 2010). In A. chilensis trees, profuse resin production associated with the lesions is frequently observed.

ID/Diagnostic: Multiple

1. Serological: An Enzyme-Linked ImmunoSorbent Assay (ELISA) Reagent Set for Phytophthora (AGDIA, Cat# SRA 92600/1000) at the genus level for primary screening. A positive does not indicate P. austrocedrae.

ID must be confirmed by other methods.

2. Morphological: Samples of inner bark (phloem) tissue from lesion margins may be directly plated on a variety of selective media (PARNBP, PAR, NAR, BARP with a corn meal agar base and SMA + MRP1) immediately after collection or after washing necrotic tissue with running tap water for 24 to 48 hours (Greslebin et al., 2007; Green et al., 2012).

After initial isolation, colonies are transferred to a non-selective medium such as clarified V8 juice agar or tomato juice agar and stored for about six weeks at 16 to 17�C (60.8 to 62.5�F) in the dark until final identification can be made (Greslebin et al., 2007; Green et al., 2013). Greslebin (personal communication) found that much more growth occurred in media amended with beta-sitosterol. With media containing low or no sitosterol, sitosterol should be added to the medium.

3. Molecular methods are being validated by the CPHST Beltsville laboratory. The approved methods will be updated after the validation is completed.

Disease symptoms caused by P. austrocedrae can be confused with other pathogens including other Phytophthora species. P. cinnamomi, a pathogen which is already present on a range of host plants in the United Kingdom (UK) and in the United States, can cause similar symptoms to P. austrocedrae on ornamental hosts. Physical damage caused by heavy snow or drought might result in similar browning of the foliage, but there would be no associated lesions (Forestry Commission, 2013). Phytophthora lateralis has been found to infect C. lawsoniana in the UK with similar host symptoms (Green et al., 2013).

A real time PCR method for P. austrocedrae identification has recently been developed but is not yet published (Green, 2013, personal communication). Update: This method has now been published (Mulholland et al., 2013).

Online Identification Tools to Phytophthora: Lucid Key, Tabular key, and Sequencing Analysis, an identification tool that will enable morphological and molecular identifications of Phytophthora spp. including P. austrocedrae, is in progress in the CPHST Beltsville lab (Dr. Gloria Abad) in collaboration with the CPHST Identification Technology Program (ITP) in Fort Collins, CO. This tool has an anticipated delivery date of spring 2014.

This pathogen is known to occur in Argentina (Patagonia), Chile, and Great Britain (England, Scotland, and Wales).

Research implicates P. austrocedrae as the cause of disease in the following hosts:

Austrocedrus chilensis (Chilean cedar, Cordilleran cypress), Chamaecyparis lawsoniana (Lawson cypress), Chamaecyparis nootkatensis (Nookta cypress), and Juniperus communis (common juniper), and Juniperus horizontalis (creeping juniper).