Histopathology of Cowpea Roots Co-infected with Root-Knot Nematode, Meloidogyne incognita and Wilt Fungus, Fusarium oxysporum

Histopathological studies of cowpea infected with Meloidogyne incognita and Fusarium oxysporum showed presence of giant cells in susceptible cultivar Pusa Komal and no giant cells in resistant cultivar, C-152. Gall diameter index was greater in nematode alone and minimum in treated one where reduced dose of both neem cake and carbofuran was applied. In neem cake treated roots giant cell formation did not distort the vascular cylinder's original form. Abundant conidia of Fusarium oxysporum was observed in cortical cells and xylem vessels in fungal inoculated treatments. The mean number of nuclei in giant cells varies from 12 to 34. In nematode + fungus inoculated roots conidia could be observed in the cortex as well xylem vessels adjacent to the giant cell but not inside the giant cells.