THE TOXICITY OF PHYTOTOXINS FROM CERCOSPORA-ARACHIDICOLA AND CERCOSPORIN FROM CERCOSPORA SPECIES TO TOBACCO, SWISS-CHARD AND GROUNDNUT PLANTS

Nine of the 12 species of Cercospora isolated from various plants prod uced cercosporin. Some Cercospora spp. also produced a yellow fraction and C. arachidicola produced orange and yellow-orange fractions but n ot cercosporin. Neither cercosporin nor the orange fraction were host specific and caused similar damage on Swiss chard, tobacco and groundn uts. The amount of damage and toxin concentration were positively corr elated. The orange fraction caused considerably less damage in the dar k than in the light and young leaves were more resistant to damage tha n older leaves. The yellow-orange fraction was only weakly phytotoxic.