ABSTRACT
Symptoms HAULM: Symptoms generally appear after mid-season and may resemble Fusarium or Verticillium wilts. Initially, the basal region of upper leaves rolls upward and the leaves often become distinctly purple, red, or yellow in colour (98). The rolling gradually spreads to leaves lower down the plant and these may become flaccid and wilted (99). New leaves fail to enlarge normally, and apical dominance is lost causing aerial tubers and/or shoots with swollen bases to grow from axillary buds. Lower stems may develop cortical necrosis and vascular discoloration. Some stems on plants may remain uninfected and symptomless.
