We evaluated the effects of exposure to doses of near- irradiation (420-425 peak 366 nm) and far- (240-280 peak 254 nm) on the conidial germination, length of germ tubes and radial growth rate of Fusarium oxysporum and Aspergillus nidulans (anamorph of Emericella nidulans). Near- irradiation delay conidial germination and inhibitory effect was maximal after 240 min of irradiation. The length of developed germ tubes was reduced up to 98% and 70% in F. oxysporum and A. nidulans respectively. Far- irradiation was more effective than near- and drastically reduces the conidial germination. Irradiation for 25 min completely inhibited conidial germination in F. oxysporum while 35 min exposure caused complete inhibition in A. nidulans. The development of germ tubes was significantly inhibited and very slow after far- irradiation compared with that of near- irradiation. Radial growth was also retarded by near- irradiation especially when subjected for long periods. Far- irradiation was more effective than near- and the inhibitory effect was markedly observed during the 72 hr followed irradiation. F. oxysporum appeared to be more sensitive to - irradiation than A. nidulans.
Key words: F. oxysporum, A. nidulans, -irradiation, photocontrol, conidial germination, growth rate.
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