Centre for Phytophthora Science & Management (CPSM)

How to collect your sample for Phytophthora Dieback Analysis

Targeted sampling:

Detection rates for Phytophthora cinnamomi are always greatest when recently dead or dying plants are targeted. It is therefore preferable to use a targeted sampling approach wherever possible.

  • Sample from plants showing symptoms of Phytophthora Dieback.
  • Detection rates are higher from recently dead or dying plants than from plants which have been dead for some time.
  • In a bushland setting, where a disease front can be readily identified, sample from the active disease front where the greatest number of plants are displaying symptoms.

Collecting Soil Samples for analysis:

  • Scrape away the surface litter and collect soil down to a depth of 30 cm.
  • Each sample should consist of several smaller samples from beneath the canopy of the symptomatic plant or from several plants in a close proximity.
  • Collect between 300-500 grams of soil and fine root material.
  • Place samples in a sterile, durable sampling bag and store at a stable temperature until delivered to the laboratory for analysis.
  • Label your sample using a permanent marker so that it is clearly visible.
  • Use an appropriate label which is consistent with that on the Sample Submission Form.
  • Avoid leaving samples in direct sun light, in a hot car or similar. We recommend placing into an Esky or insulated foam box for transport.

Collecting plant material for analysis:

Phytophthora cinnamomi can be readily isolated from the active lesion front of infected plants. Such lesions may not always be found on infected plants as the lesion front may not get to the collar before the plant dies. Lesions may be identified by removing the bark and slicing into the cambium layer at the collar of the plant or exposed root using a machete, mattock or similar tool.

  • Once the lesion front is found collect a slice of wooded material including both healthy and diseased wood and submit for analysis.
  • Only a slice of the lesion front is required to isolate the pathogen, so limit samples to several slices with a maximum of 300 grams per sample.
  • Only submit samples where a distinct lesion front has been identified.
  • P. cinnamomi is generally not isolated from healthy material above the lesion front in infected plants and is usually restricted to the lower trunk.

Sampling Water:

In recent years CPSM has utilized water baits as a means of detecting P. cinnamomi from environmental water samples. This is a useful tool for targeted sampling and monitoring under certain conditions and we recommend water baiting for ongoing analysis in contained environments which are conducive to the pathogen’s growth such as nurseries and horticultural water supplies. We are however, not recommending water baiting for untargeted environmental detection of P. cinnamomi in Western Australian water systems at this time due to the excessive sampling effort involved and low rates of detection meaning that other field based assessments are more effective at this time.

We are continuing our research in this area to make this a more robust technique and hope to be able to recommend and utilize water baiting for catchment-level monitoring in the near future.