Vertical and horizontal distributions of plant - parasitic nematodes associated with banana CV. Williams under flood irrigation regime

Under flood irrigation system, the vertical and horizontal distributions of plant-parasitic nematodes associated with soil and roots of banana cv. Williams were investigated. The sampling data generally indicated that the highest population density of parasitic nematodes viz. Criconemoides spp., Helicotylenchus exallus, Hoplolaimus spp. and Meloidogyne incognita were concentrated at soil depth layers of 0-15 cm, and 16-30 cm at the horizontal distance of just beneath the plant base [zero cm] and 40 cm from the banana pseudostem base which is correlated with the growth and distribution of the feeder roots of banana. These sites should be considered as the best sampling points for such coin habiting nematodes

Histopathological changes induced by either Root - Knot or spiral nematedes on banana roots

Cross and longitudinal sections in roots of banana cv. Williams infected by either Meloidogyne incognita or Helicotylenchus dihystera showed that the histological alterations induced in roots infected with M. incognita were displayed by the giant cell formation in both cortical and stelar regions. The giant cells were, always, in clusters each containing 3-6 cells. Roots infected with H. dihystera showed small brown lesions around the penetratedsites in the cortical layer causing considerable cell wall damage. The walls of the invaded cells by the nematodes were heavily stained with safranine indicating the presence of lignin, while healthy cell walls were lightly stained