VIEW ARTICLE

A Disease Complex of Okra and Tomato Involving the Nematode, Meloidogyne incognita, and the Soil-Inhabiting Fungus, Rhizoctonia solani. J. K. Golden, Research Associate and Professor of Nematology, Departments of Nematology and Plant Pathology, University of California, Riverside, California 92502, Current address of senior author: Biochemicals Department, E. I. duPont deNemours and Co., Inc., Atlanta, Georgia 30326; S. D. Van Gundy, Professor of Plant Pathology, Departments of Nematology and Plant Pathology, University of California, Riverside, California 92502. Phytopathology 65:265-273. Accepted for publication 2 July 1974. . DOI: 10.1094/Phyto-65-265.

Galled okra and tomato roots infected with Meloidogyne incognita in the field and in the greenhouse were highly susceptible to infection by Rhizoctonia solani. Root decay by the fungus occurred 4-5 weeks after nematode infection. Fungal sclerotia were formed only on nematode gall tissues. The fungus penetrated either directly or through ruptures in the root created by the mature female nematode. Rhizoctonia solani colonized nematode giant cells and root xylem cells. Vascular discoloration occurred both in roots and stem, however no fungus was isolated from stems. Prepenetration studies using cellophane membranes indicated that the fungus was specifically attracted to nematode gall tissue and that sclerotia were selectively formed on nematode galls. During development of the nematode in okra, the levels of total carbon and nitrogen were higher than in control roots.