Fungitoxic effects of some plant extracts on seedborne fungi pathogens of Bambara groundnut in Awka South of Anambra State, Nigeria

The research was carried out to test the effect of turmeric and garlic extracts on seed borne fungi pathogens of Bambara groundnut (Vigna subterranean) in Awka South of Anambra State Nigeria. Seed health test of Bambara groundnut seeds sampled from Awka main market was achieved by blotter paper method. The potentials of the isolated organisms to cause diseases was tested in a pathogenicity test using Koch's procedures. Antifungal effect of methanol and ethyl acetate extracts of tumeric (Curcuma longa) and garlic (Allium sativum) was investigated in an in-vitro experiment against the isolated seed borne pathogens of Bambara groundnut and synthetic fungicide (Mancozeb) as a standard control. The result of pathogenicity test revealed that Aspergillus niger, isolated from Bambara groundnut seeds was pathogenic. The result also showed that all the two plant extracts and synthetic fungicide were effective in inhibiting radial growth of Aspergillus niger which was the only fungi pathogen isolated. Curcuma longa performed closely rated to Mancozeb in the in-vitro experiment, having (75.00, 75.00 and 75.00%) and (72.56, 60.82 and 50.94%) respectively in the three days in culture. The higher the concentration the higher the inhibition values as 30 g/ml consistently gave the highest inhibition values. Also Soxhlet extraction method did better than cold maceration in days 2, 3 in culture. The research have shown that fungitoxic compounds from Curcuma longa could be explored as an eco-friendly alternative to synthetic fungicide (Mancozeb) in the control of Aspergillus niger on Bambara groundnut seeds.