Bacterial stem & root rot

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Causal organism: Erwinia chrysanthemi Burkholder, Mc Fadden & Dimock


Other names: Bacterial soft rot, bacterial wilt, bacterial wilt and root  rot, shell rot  


Blackening of stem caused by Erwinia chrysanthemi (V. Duarte).


Bacterial rot on storage root (C. Clark, APS).

Diagnostic summary

  • What you see on plants


    - initial symptom is the partial wilting of the plant,  eventually  entire plant may collapse.

- water-soaked, sunken brown to black lesions are observed at the base of  stems and on petioles. Discolouration of tissues inside the stem may also occur.


- fibrous roots have localized lesions  but the entire root system can be affected, with characteristic black, water-soaked appearance.


- storage roots  have small, sunken brown lesions with black margins; more frequently the rotting is internal with no evidence outside. Affected tissue becomes  watery.


- there is a peculiar smell produced in infected tissues, due to the invasion of saprophytes that live on decomposed organic matter.

  • More common in storage but may also affect plants in the field and in seedbeds.

  • Attack on sweetpotato has only been reported from USA but is also suspected to occur in the Philippines.


Economic importance

Geographical distribution



Biology and ecology

Host range





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