Jan 5, 2004

Ralstonia SymptomsSource: Various

Though not new information, with the new outbreak, you may need to re-familiarize yourself with the most common Ralstonia symptoms. Symptoms of Ralstonia solanacearum race 3 biovar 2 are reportedly similar to those of Xanthamonas, another strain of southern bacterial wilt, and include wilting plants, usually affecting the lower leaves first, followed by abnormal yellowing of leaves and finally death of the leaf tissue. While it can be confused with Xanthomonas bacterial blight if only wilting plants are present, Ralstonia does not cause leaf spots, whereas Xanthomonas may.

The Ralstonia bacterium enters the root system, moves through the vascular system, and eventually causes wilt. Ralstonia doesn’t spread easily from plant to plant, except through re-circulated irrigation water or stem-to-stem transmission via cutting knives or manual cleaning and pinching when the laborer has not sanitized between plants. R. solanacearum race 3 biovar 2 can be in the plant without causing symptoms under cool conditions, but disease may be expressed later. The bacteria can also lay dormant in soil and water for an extended period of time. Growers can prevent disease spread to additional hosts in the greenhouse by avoiding subirrigation of any of the known Ralstonia hosts.