TOBACCO

          Bacterial wilt or Granville wilt (first reported in Granville County, North Carolina) initially appears as wilting of one or two young leaves during the hot hours of the day with recovery during the cooler evening.  If conditions are optimal, wilt progresses rapidly with the leaves remaining green.  In some cases, the wilt will be unilateral.  If the environment is suboptimal, wilt develops slowly with the leaves turning light green and then progressively yellower.  Necrotic areas frequently appear between the veins and at the leaf margins.  During hot, dry conditions, wilted leaves become irregularly scalded and do not detach from the stem.  Tobacco stem symptoms resemble tomato stem symptoms (7).


Initial wilt symptoms of the lower leaves.
 Unilateral wilt of infected tobacco plant.


Tobacco plant showing relatively severe
symptoms of Granville wilt.
 Longitudinal section of a tobacco stem
showing the browning vascular system.
(Photos courtsey of H. D. Shew, North Carolina State University)


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