Host status differences and their relevance to damage by Meloidogyne incognita

Four populations of #Meloidogyne incognita$ were tested on 57 species of plants from temperate and tropical regions. Juveniles of one or more populations invaded, and induced galls on almost all plants. Except for the population from the West Indies which induced most galls on #Nicotiana$ spp., there was no obvious relationship between the origins of populations and their ability to induce galls on plants from particular regions. Although most plants were hosts for all four populations, many produced only few galls/egg masses with some of the populations. The differences in galling between populations, and the interaction with plant species were both significant (P is less 0.001). Poor hosts often contained fewer juveniles and the rate of juvenile development was often decreased compared with good hosts. #Solanum nigrum$ was an exception in that it was invaded by fewer juveniles than susceptible tomato, but rates of development were similar. The effect of host status differences in four plant species on damage by #M. incognita$ was investigated but only the growth of susceptible tomato was decreased. The growth of the non-host #Urtica dioica$, of the poor host #Datura metal$, and of an intermediate host #S. nigrum$, was unaffected. (Résumé d'auteur