- Correspondence (232)
- Departmental Biographical Information (153)
- Rockefeller Foundation Related Correspondence and Related Materials (152)
- Commissions, Conferences, Councils and Symposia, 1952 2001 (135)
- Plant Pathology Department University of Minnesota and United States Department of Agriculture (127)
- Subject Files, 1950 2006 (109)
- Field Notebooks and Appointment Books, 1948 2000 (98)
- Correspondence, 1954 2006 (94)
- Professional Activities (78)
- Plant Pathology Seminar (76)
- People and Miscellaneous Topics (73)
- Other Professional and Personal Correspondence, 1926 1976 (67)
- Departmental Records (62)
- Professional Affiliations, 1941 2006 (58)
- Photographs (57)
- Correspondence by Geographical Region (40)
- Clipping Files, Undated, 1962 2000 (36)
- Rockefeller Foundation Related Materials (36)
- Cimmyt (35)
- Miscellaneous (28)