Effect of simultaneous inoculations and prior establishment of Heterodera zeae, Meloidogyne incognita and Tylenchorhynchus vulgaris on penetration of cyst and root-knot nematodes into Maize roots*

Larval penetration of Heterodera zeae and Meloidogyne incognita into maize roots (Cv. Ganga 5) continued upto 7 days with majority being achieved by 4th day. H. zeae penetrated root tissues at both meristematic and zone of elongation as compared to M. incognita which predominantly invaded at meristematic zone. In case of simultaneous inoculations M. incognita did not seem to interfere with the penetration of H. zeae while penetration of M. incognita was adversely affected by presence of H- zeae. On the other hand, T. vulgaris tended to enhance the penetration of M. incognita. Prior establishment of any of the nematode species by three days either singly or in combination significantly reduced invasiveness of the other species. Larval penetration of both cyst and root-knot nematodes was more whenever they were inoculated earlier.