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Bacterial wilt has been detected in five samples submitted to the Plant Diagnostic Lab in the past week.  This includes samples collected from both commercial fields as well as backyard gardens.  Bacterial wilt is caused by a soil-borne bacterium (Ralstonia solanacearum). A characteristic of this disease, which sets it apart from other wilt diseases, is that plants wilt and die rapidly without the presence of yellowing or spotting of the foliage. The disease can occur in newly cleared land as well as in areas where susceptible crops have not been grown previously. The bacterium often enters a field on infested transplants, equipment or through drainage water. The pathogen can overwinter in soil.

Bacteria infect plants through the roots or stem, most often where tissue has been injured by cultivating, or by some other physical means such as nematodes. Bacteria invade the vascular tissue, apparently causing wilt by a gradual blocking of the water conducting vessels. The disease is most commonly found in low, wet areas of fields and is most active at temperatures above 75 degrees F.

To identify bacterial wilt, cut and peal back a section of the epidermis and cortical tissue just above the soil line. The center of the stem (pith) will, in early stages, appear water soaked; later, the pith will turn brown and sometimes become hollow (Figure 1). The discoloration of the pith distinguishes this disease from the fungal disease Fusarium wilt which can also be common in home gardens.

Bacterial wilt attacks members of the Solanaceous plant family, which includes peppers, potatoes, and eggplant, making crop rotation an effective method of control. Growing susceptible crops in the same area no more than once every 4 years will reduce inoculum in the soil. Removing wilted plants and the soil surrounding their roots can reduce spread of the disease and may be a viable control alternative in home garden situations. Soil solarization is another alternative for control of bacterial wilt. See more articles on this disease here.


Figure 1.  Discoloration of pith of plant infected with bacterial wilt.  


Edward Sikora and Kassie Conner

Extension Specialist, Plant Pathologist, ACES



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