Ralstonia solanacearum (= Pseudomonas solanacearum)
Most severe in tropical and subtropical climates with high rainfall
and warm temperatures
World Vegetable Center
Wilting first appears on the youngest leaves of plants
during hot daytime temperatures. The infected plants
may recover, temporarily, in the evening, when
temperatures are cooler. A few days later, a sudden
and permanent wilt occurs.
The roots and lower portion of the stem have a
browning of their vascular system. The invaded roots
may rot due to infection from secondary bacteria.
Diseased stems that are cut and placed in a small
container of water will show yellowish or grayish bacterial
ooze coming from the cut end.
When conditions are less favorable for disease
development (for example, cool and dry), the infected
plants may only show signs of stunting, and adventitious
roots may develop on the main stems. The lower leaves
will turn yellow before wilting symptoms occur.
Symptoms of this disease are distinguished from
those of bacterial canker, which causes leaf chlorosis,
stem cankers, and “bird’s eye” spots on fruits. Bacterial
wilt symptoms are distinguished from those of Fusarium
wilt because of the rapidity of the wilt, under favorable
conditions, for the former, and the drier, firmer stem rot
of the latter.
Plants wilt, first on the lower leaves during a hot day and then recovering at night. A few days later, a sudden
and permanent wilt occurs (left photo). Look for brown discoloration of the vascular system (middle photo). An
ooze will flow from a cut, infected stem (compare uninfected versus infected stems in right photo).
How to Identify Bacterial Wilt
Written by Ray Cerkauskas, Visiting Scientist from Agriculture and Agri-Food Canada. Edited by Tom Kalb.
Published by AVRDC – The World Vegetable Center; P.O. Box 42, Shanhua; Taiwan 741; ROC.
tel: (886-6) 583-7801; fax: (886-6) 583-0009; email: firstname.lastname@example.org; web: www.avrdc.org
Conditions for Disease Development
Soil is the primary source of the