Description: Papers of James T. Barrett '03, A.M. '07, assistant (1903-08) and associate (1910-13) in Botany at the Agricultural Experiment Station at Illinois and professor of plant pathology at the University of California, including correspondence with Thomas J. Burrill (1908-10, 1914-15) and plant pathology research and publications; and a Radish black root disease survey of Illinois (1908), including lists of vegetable gardens, questionnaires, maps and correspondence with fieldman J.J. Davis. The series also includes correspondence on mycorrhiza fungi (1949-62); research notes and publications on Rhizophagus (1951-61) and correspondence with J.W. Gerdemann (1961).