- Lead scientist
- Geoff Denton
- Start date
- 2008
- End date
- 2011
- Keywords
Phytophthora, Pythium, pathogenicity, Taxus baccata, yew, UK Gardens, RHS Advisory Service
- Benefits to gardeners
This project is a study on the aggressiveness of various Phytophthora and Pythium species isolated from Taxus through the RHS advisory service on Taxus baccata (yew). The results will allow better advice to be given through the RHS advisory service about control measures.
- The problem
From our preliminary Phytophthora survey data and advisory records, it was found that Taxus has the highest number of Phytophthora enquiries. It accounts for about 20% of the positive Phytophthora enquiries, with the next highest of around 6% recorded from Rhododendron.
Additionally, from our records Taxus has been recorded with the most number of Phytophthora species. Six Phytophthora species and a Pythium species have all been recovered from dead or dying plants through the RHS advisory service. All the species recovered are known plant pathogens, but their relative aggressiveness towards Taxus is not recorded. These studies will gather information about which of the Phytophthora species and Pythium species we have recovered show the fastest disease progression.
- Approach
The RHS has collected cultures of Phytophthora species and Pythium species from samples received through the member’s advisory service. From the collection a single culture for each of the six Phytophthora species and one Pythium species was chosen. These cultures, or isolates, were selected based on two criteria:
- Pathogenicity: Isolates shown to infect susceptible bait host under laboratory conditions
- Genetic homology: The genetic diversity of isolates within each single Phytophthora or Pythium species was tested. The representative isolate was chosen to conform to the genetic fingerprint that matched the majority.
A single isolate was chosen that fits the pathogenicity and genetic homology criteria, for each Phytophthora and Pythium species. These were cultured and then used to inoculate Taxus plants. This trial has enough replication of inoculated Taxus plants to validate any results gathered, with 440 plants being used in total.
This study is currently ongoing, with the first inoculated Taxus plants still being assessed. Assessments are recording visible foliage and roots symptoms.
- Further information
Read more about Phytophthora bleeding canker
Advice about damping off
Read about Phytophthora diseases
Read about comparison of techniques for Phytophthora detection
Read the Phytophthora survey
Read about Pythium: A garden pathogen