Isozyme patterns of exotic Meloidogyne spp. populations.

Isozyme patterns of esterase (EST), malate dehydrogenase (MDH) and superoxide dismutase (SOD) were used to determine the species of 13 Meloidogyne isolates from populations originating from India (6), Venezuela (5), Cuba (1), and Egypt (1) and collected from different hosts (groundnut, Coffea arabica, tomato, sweet potato, cassava, guava and grape). It was possible to characterize most of the populations tested as M. incognita and M. javanica, but only some of them showed the typical species-specific EST phenotypes. Atypical EST phenotypes were also obtained, which made identification possible only by comparison of additional MDH and SOD phenotypes. By means of a combination of EST and MDH phenotypes, one population collected from guava in Venezuela and one population from tomato in Cuba were both identified as M. mayaguensis. Although SOD patterns did not clearly discriminate between M. incognita and M. mayaguensis, they showed the greatest polymorphism among populations, with a total of 8 polymorphic bands detected.