Cowpea Resistance to Root Knot Caused by Meloidogyne incognita and M. javanica. T. A. Swanson, Former Graduate Student, Department of Nematology, University of California, Riverside 92521. S. D. Van Gundy, Professor, Department of Nematology, University of California, Riverside 92521. Plant Dis. 68:961-964. Accepted for publication 25 April 1984. Copyright 1984 The American Phytopathological Society. DOI: 10.1094/PD-68-961.

Cowpea cultivars were tested for suitability as hosts for Meloidogyne incognita and M. javanica by comparing the numbers of eggs produced on root systems. Reproduction by both nematode species was lower on cultivars Magnolia Blackeye, California Blackeye No. 5, Mississippi Silver, and Mississippi Purple than on other cultivars tested. M. javanica produced 10–20 times more eggs on Magnolia Blackeye, Mississippi Silver, and Mississippi Purple. Some variability in cultivar suitability for the four M. incognita races was also found. Most notably, California Blackeye No. 3 was resistant to race 4 but Queen Ann was not. The results support the hypothesis that root-knot resistance in cowpea is ineffective for a California population of M. javanica.