Friday, June 9, 2023
University of Hawaii at Manoa
University of Hawaii System
College of Tropical Agriculture and Human Resources


The ginger bacterial wilt pathogen is the soil- and water-borne bacterium, Ralstonia solanacearum race 4. 

Ralstonia solanacearum race 4 in culture.
Photograph: Donald Gardner (1999) from (

Synonyms and nomenclature: Pseudomonas solanacearum (Smith, 1896) Smith 1914; Burkholderia solanacearum (Smith, 1896) Yabuuchi et al. 1992; and many others. For more information about the taxonomy of the pathogen, visit this page: link.

Ralstonia solancearum spreads by infested soil adhering to hands, boots, tools, vehicle tires and field equipment, water from irrigation or rainfall, and infected ginger rhizomes (Janse 1996). 

 Ralstonia solanacearum infects ginger roots and rhizomes through openings where lateral roots emerge or wounds caused by handling, parasitic insects or root-knot nematodes (Swanson et al. 2005).

The pathogen survives in soils within infected plant debris in soils and as free bacteria.

Geographic distribution:
The pathogen is widely distributed in many locations where ginger has been grown previously in Hawaii.

Crop losses:
Crop loss can be complete in heavily infested soils.

Use as a biological control agent for kahili ginger?
 No. Although the Wikipedia site ( indicates that R. solanacearum race 4 could be used as a biological control agent for kahili ginger, this is not true. Even if the pathogen could cause significant disease on kahili ginger, applying it upslope of ginger fileds in Hawaii would pose significant risk to the ginger crops.

Host range: Ralstonia solanacearum race 4 is restricted to edible ginger (Zingiber officinale)
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