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Soil Is Not a Reservoir for Phellinus noxius.
Zong-Chi Wu1, Ya-Yun Chang1, Qiao-Juan Lai1
1Department of Plant Pathology and Microbiology, National Taiwan University, Taipei City 10617, Taiwan.
Phytopathology
|October 5, 2019
Summary
Phellinus noxius, the cause of brown root rot (BRR), is not a soilborne pathogen. Diseased host tissues, not soil, are the primary source of P. noxius inoculum, making them the focus for sanitation and detection efforts.
Area of Science:
- Plant Pathology
- Mycology
- Forest Pathology
Background:
- Phellinus noxius causes significant tree damage through brown root rot (BRR).
- Inoculum sources for P. noxius have traditionally included basidiospores and infected host tissues.
- The role of soil as a reservoir for P. noxius has remained unclear.
Purpose of the Study:
- To determine if Phellinus noxius can survive or establish in soil independently of host tissues.
- To investigate the dissemination of P. noxius from infected roots into surrounding soil.
- To assess the potential of soil at infection sites to act as an inoculum source for new infections.
Main Methods:
- Soil sampling at P. noxius infection sites before and after diseased tree removal.
- Soil plating assays to isolate viable P. noxius colonies.
- DNA-based detection of P. noxius in soil, including rhizosphere and non-rhizosphere samples.
- Experimental inoculation of soil with P. noxius arthrospores and monitoring of DNA persistence after soil treatments (flooding, fumigation).
- Replanting susceptible loquat (Eriobotrya japonica) in cleaned-up infection sites to test for disease development.
Main Results:
- No viable P. noxius colonies were recovered from soil samples collected at infection sites.
- While P. noxius DNA was detectable in soil, viable fungal isolation was unsuccessful, even from rhizosphere soils.
- P. noxius DNA persisted in soil for several weeks after the fungus was eradicated by flooding or fumigation.
- Replanted loquat trees in cleaned-up sites remained healthy, indicating the soil did not harbor infectious inoculum.
Conclusions:
- Phellinus noxius is not a soilborne pathogen; its survival and spread are primarily linked to infected host tissues.
- Diseased host tissues are the critical focus for effective field sanitation and diagnostic efforts against brown root rot.
- Current management strategies should prioritize the complete removal and disposal of infected woody debris to prevent disease spread.
Keywords:
Phellinus noxiusbrown root rotdisseminationloquatmolecular detectionrhizospheresoil platingsurvivalMore Related Videos
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