Continuous and over use of fungicides to reduce phytopathogens has
harmful effect on health and induces natural resistance in plant
pathogens. Present study aimed to use natural compound such as
chitosan to inhibit growth of Fusarium spp. isolated from soil of Egyptian
governments (Kafr El-sheikh, El-Gharbia, and El-Monofia), Fusarium
isolates identified based on morphological characteristics as Fusarium
oxysporum, F. solani, F. verticolliodes, and F. chlamydosporum. Potato
dextrose agar medium (PDA) containing 1.6 g/L of chitosan acetic acid
distilled water solution recorded remarkable mycelial growth inhibition
(77, 76.7 , 71.4 and 67%) for Fusarium verticilloides, F. oxysporum, F.
chlamydosprum and F. solani respectively. Ultrastructural changes in
conidia of F. chlamydosprum treated with 1.2g/L chitosan acetic acid
distilled water solution were also investigated by means of transmission
electron microscopy (TEM) which indicated alterations of cytoplasm and
cell wall thickness, compared with control.