A greenhouse study with 10 annual plant species was carried out with the purpose of detecting differences in host capacity to five populations of Nacobbus aberrans. The reaction of the plants to N. aberrans infection indicated three distinct groups of populations among the five tested. A suggested race classification for N. aberrans is proposed which defines "race Na-1", "race Na-2" and "race Na-3" based on the ability to reproduce on Lycopersicon esculentum cv. Rutgers, Phaseolus vulgaris cv. Negro Queretaro and Beta vulgaris cv. Ford Hook Giant.
