Interspecific correlation and regression analyses of population densities of Tylenchorhynchus spp., Rotylenchulus reniformis and Hoplolaimus indicus indicate very weak interspecific competition among these plant-parasitic nematodes owing to their differential ecological niches on the same host. The kind and extent of correlation was determined by the host and the season, especially temperature. Tylenchorhynchus spp. and R. reniformis populations were usually negatively correlated. Mustard suppressed both these nematodes. Tylenchorhynchus spp. and H. indicus were positively correlated under wheat and pea in the Rabi season but negatively under mung, okra and fallow in summer. R. renijormis and H. indicus were usually positively correlated in both seasons. The rates of change in the population densities of anyone nematode with unit change in the population of the others was a function of the rates of reproduction, host preference and the prevailing temperature.
Interspecific correlations, Populations
