VIEW ARTICLE

Interrelationship of Heterodera glycines and Phytophthora megasperma var. sojae in Soybeans. M. O. Adeniji, Senior Lecturer in Plant Pathology, Department of Agricultural Biology, University of Ibadan, Nigeria; D. I. Edwards(2), J. B. Sinclair(3), and R. B. Malek(4). (2)Research Plant Pathologist, Agricultural Research Service, U.S. Department of Agriculture, Regional Soybean Laboratory, University of Illinois, Urbana 61801; (3)(4)Professor of Plant Pathology, and Assistant Professor of Nematology, respectively, Department of Plant Pathology, University of Illinois, Urbana 61801. Phytopathology 65:722-725. Accepted for publication 18 February 1975. DOI: 10.1094/Phyto-65-722.

Soybean (Glycine max) seedlings (2-, 5- and 10-days-old) of three cultivars varying in susceptibility to race 3 of the soybean cyst nematode (Heterodera glycines) and race 1 of Phytophthora megasperma var. sojae (Pms) were inoculated with each organism alone and in combination. Seedling disease was more severe in the Pms-susceptible cultivars Corsoy and Dyer when both organisms were present, than when Pms alone was present. Pms-resistant Harosoy-63 did not develop symptoms in the presence of both organisms. Mechanical wounding of seedlings did not appreciably influence resistance. Pms-infection significantly reduced the population of H. glycines on roots of Corsoy but did not break resistance of Dyer to the nematode. Pms appeared to be the dominant pathogen in the disease complex.