MOHAMED MOHAMED YOUSSEF YOUSSEF B. Sc. Agtic. (Plant Pathology), Ain Shams Univ., 1994

Abstract

Isolation and identification methods revealed that four aggressive isolates of S. roljsii namely, Sr-1 , Sr-2, Sr-3 and Sr-4 were markedly differed. The two isolates, Sr-1 and Sr-3 proved to be more pathogenic against the tested pepper and tomato plants, respectively. Pathogenicity tests of S. ro/f'iii and M incognita for both hosts were realized. The interaction between the two pathogens was measured on disease symptom development, i.e., disease incidence, disease severity and nematode root-galling. Some interactions revealed a considerable synergism in the presence of: nematode galled-roots, high inoculum levels of fungus, soil amendments such as turnip residues, young seedlin gs and high temperature degrees. On the contrary, the other interactions reflect adequate antagonism as influenced by: low ambient temperature, some plant residues such as alfalfa and cabbage, soil microflora and antagonistic bacteria (Bacillus subtilis). Such antagonistic interactions may result in less disease incidence and more plant survival. These inhibitors could be of a considerable merit in integrated programs of fungus-nematode­ management.