الملخص

The antagonistic ability of two isolates of the biological control agents Trichoderma spp.(3,11) and isolate (1,2) of Trichoderma viride as well as Gliocladium sp. Were studied against the pathogenic fungi Alternaria alternate , Pythium sp Rhizoctonia solani Stemphylium sp., isplated from sesame seeds. Two ways of incubating the dishes, normal and inversed positions were used . The results showed high antagonistie ability of all types of the biocontrol agents used ranging was between 102 and 206 in the inversed position of the petri dishes uring inebation wich were better than in the normal position .The German isolate of T.viride gave the better degrr of antagonism among the biocontrol agents used, but were not significantly different from the rest.