Physiological Variation in the Genus Meloidogyne as Determined by Differential Hosts

Four species of root-knot nematodes, namely Meloidogyne incognita (Kofoid et White) Chitwood, M. javanica (Treub) Chitwood, M. arenaria (Neal) Chitwood, and M. hapla Chitwood have a wide host-range and are widely distributed throughout the world. For each of the species there are certain non-hosts and these are different for each species, thus making it possible, through the use of differential hosts, to identify the species as well as detect pathogenic variations within a species. A knowledge of the nature and extent of this variation is needed for the development of varieties which possess a broad base for resistance.