Interaction studies between Rhizobium leguminosarum and Meloidogyne incognita on pea (Pisum sativum L.) grown under different concentrations of molybdenum

The effect of different concentrations of molybdenum (0, 5, 10, 20, 40, 50 μg L−1) on the hatching of eggs of Meloidogyne incognita and nematode infection of pea (Pisum sativum L.) roots nodulated by Rhizobium leguminosarum was investigated at low soil pH. Inhibition in the emergence of juveniles from eggs of M. incognita was dependent upon the concentration of Mo applied in the form of sodium molybdate. Different concentrations made freshly hatched juveniles sluggish within 48 hours. Mo at the level of 30 μG L−1 was considered optimum as all the characters such as number of nodules, nitrogenase activity of nodules, leghaemoglobin content of nodules, dry weight of shoot, dry weight of root and nitrogen content of shoot were found to be maximum. Higher concentrations of Mo had a detrimental effect on symbiosis. M. incognita reduced all growth characters at all the levels of Mo when compared to uninfected nodulated plants. Nematodes caused less damage to plants at higher concentrations of Mo as reflected by the number of galls/plant and other growth characters.