1. BRETZ, T. W., PLANT DISEASE REPORTER 30: 156 (1946).
2. DELONG, D. M., AMERICAN MIDLAND NATURALIST 17: 965 (1936).
3. DeLong, D. M., Proceedings of the Entomological Society of Washington 41: 33 (1939).
4. Illinois Agricultural Experiment Station Bulletin 1912 154
5. Garman, H., Kentucky Agricultural Experiment Station Bulletin 47: 1 (1893).