Antifungal activities of black seed, castor and lemon oils against pathogenic plant fungi

Abstract

Pathogenic plant fungi are of great concern due to their effects in reducing crop yield. Plant oils are environmentally friendly alternatives to non-biodegradable synthetic fungicides. This study investigated the potency of some plant oils in vitro against pathogenic plant fungi. Fungi were isolated from infected leaves of soybean, cowpea, groundnut and maize cultivated on the same farm land. These fungi were identified as Rhizoctonia solani, Mucor racemosus, Fusarium verticillioides, Flavodon flavus and Aspergillus flavus. Preliminary testing of the antifungal effects of black seed, castor, and lemon oilwas carried out against the isolated fungi using standard procedures. The results identified which of the tested plant oil demonstrated antifungal potential against the fungi species. Lemon oil and black seed oil showed the most promising effect due to their broad-spectrum mycelia inhibitory effects on the pathogenic fungi. Lemon oil was fungicidal against F. verticillioides and F. flavus in this study. Sporulation in F. flavus were also inhibited by the two oils. Lemon and black seed oils are suggested as promising candidates for further research in vivo and are major components for fungicides. This work has demonstrated the potency of plant oils as an important economical and environmentally friendly alternatives to non-biodegradable synthetic fungicides.