THE EFFECT OF MELOIDOGYNE INCOGNITA ON GROWTH OF SUNFLOWER IN POTS

The effect of Meloidogyze incognita host race 1 on the growth of sunflower was investigated in a glasshouse experiment. Pots were infested with finely chopped nematode-infected tomato roots to give a range of population densities of 0, 0.062, 0.125, 0.25, 0.5, 1, 2, 4, 8, 16, 32, 64, 128, 256 or 512 eggs and juveniles/cm³ soil. Tolerance limits (T) of 1.85, 2.37 and 2 eggs and juveniles of M. incognita/cm³ soil were estimated for top weight, height and number of nodes of sunflower plants, respectively. Minimum relative yields (m) were 0.25, 0.3 and 0.5 for top weight, height and number of nodes of sunflower plants, respectively. The maximum rate of nematode reproduction on sunflower,about 81, occurred at the lowest initial population of the nematode.