A bacterial leaf spot disease on corn (Z ea mays L.) has been under observation in Iowa since 1916. In the fall' of 1924, it was quite prevalent on Zea mays, and on volunteer sorghum (Holcus sorghum L.) growing together near Ames, Iowa. Further examination revealed the presence of a somewhat similar leaf spot on Holcus sorghum, sudan grass [H. s01'ghurn val'. sudanensis (Piper) Hitchc.]' Johnson grass (H. halepensis L.) and pearl millet [Pennisetum glancttm (L.) R.Br.]. 'fhese observations led to a cultural study of the causal agents and a survey of the literature on bacterial diseases of these hosts.