EFFECTS OF THREE MEDICINAL PLANT EXTRACTS ON LEAF WILT AND STEM ROT DISEASES OF SESAME (Sesamum indicum L).

Abstract

Leaf curling, wilting and yellowing of sesame plant caused by Fusarium oxysporum and stem rot caused by Rhizoctonia solani are destructive diseases affecting sesame, throughout the world. Despite the success of several synthetic chemicals to curb this menace, their use has been discouraged, due to their negative impact on the ecosystem. This study was therefore designed to annex the use of botanicals, which seems to be a trend in tackling plant diseases. 1The pathogens were isolated from infected sesame collected from farmers' field; they were morphologically identified using standard mycology keys and hereafter authenticated using molecular tools. Pathogenicity was conducted and the pathogenic effects of both pathogens on sesame were confirmed. Three extracts which are Murraya koenigii, Azadirachta indica and Alium cepa at 50 and 100 g/l were screened using food poisoning technique. Mancozeb and distilled water were used as positive and negative controls respectively. Results revealed that the methanolic extracts of the three plants were highly effective at 50 and 100 g/l against the mycelial radial growth of the tested pathogens. However, M. koenigii extract was more effective at 100 g/l against both F. oxysporum and R. solani with mycelial growth inhibition rate of (100% and 96% respectively) while A. indica had (94.67% and 91%) and A. cepa has (71% and 50%). At 50 g/l the three plant extracts showed some inhibitory effects with A. cepa being the least, having 38.33 o, and 61% inhibitory rate on F. oxysporum and R. solani respectively. M. koenigii being the best in controlling both pathogens (with an inhibitory rate of 100%) can serve as a good candidate for the development of ecofriendly bio-fungicide against these tested plant pathogens