NJAFE VOL. 9 No. 1, 2013 72 EFFECT OF AQUEOUS AND n-HEXANE EXTRACTS OF Khaya ivorensis A Chev (Meliaceae) ON THE CONTROL OF RICE SEED-BORNE FUNGI

Abstract

Experiments were carried out to test the effect of aqueous and n-Hexane extracts of Khaya ivorensis on the control of rice seed-borne fungi. Seed-borne fungi associated with the seeds of five rice varieties (NERICA 5, FARO 29, FARO 49, NERICA 18 and NERICA 36) were isolated using the agar plate incubation method. N-hexane and aqueous leaf extracts of Khaya ivorensis were tested at 5% v/v and 10% v/v of the culture medium on Fusarium verticilloides, one of the most predominant fungi, isolated from the seeds. Methanol alone applied at 5%v/v of the culture medium served as the control while Carbendazim (a benzimidazole fungicide) applied at 1g/litre served as a check. Inhibition of mycelia growth/diameter was recorded as a measure of the effectiveness of the extracts. The results of the experiment showed a significant reduction (p>0.05) in the diameter of growth of the test fungus treated with the extracts compared to the control. N-hexane leaf extract of khaya ivorensis at both concentrations performed better than the aqueous extract in reducing the growth of the test fungus at the different days after plating studied. This portends great opportunities in the use of botanical pesticides as antimicrobial agent in seed-borne infection.