PATHOGENICITY OF MELOIDOGYNE INCOGNITA ON KENAF IN MICROPLOTS[supa][sup)]

The relationship between initial population densities (Pi) of Meloidogyne incognita and growth of kenaf was investigated in the field. Microplots were artificially inoculated with finely chopped nematode-infested tomato roots to give a range of initial population densities (Pi) of 0, 0.062, 0.125, 0.25. 0.5, 1, 2, 4, 8, 16, 32, 64, 128 or 256 eggs and juveniles of M. incognita/cm³ soil. Tolerance limits (T) of 0.129, 0.18, 0.32 and 0.67 eggs and juveniles/cm³ soil were calculated for top fresh weight, stem weight, height and stem basal diameter of plants, respectively. Minimum relative yields (m) of 0.05, 0.1, 0.3 and 0.4 were also calculated for fresh top weight, stem weight, height and basal stem diameter of plants, respectively. Maximum nematode reproduction rate (Pf/Pi) was 588 at low Pi and decreased with increasing nematode population density.