Fungitoxic Activity of Neem and Pawpaw Leaves Extracts on Alternaria Solani, Causal Organism of Yam Rots

The in vitro fungitoxic activity of crude extracts of neem (Azadirachta indica) (A.) Juss) and pawpaw (Carica papaya) (L.) on Alternaria solani, isolated from rotting yam tubers whose pathogenicity has been proven and assessed. The organic solvent (methanol) extracts of leaves of neem and pawpaw at 20%, 40%, 60% and 80% concentrations were tested on potato dextrose agar (PDA) for activity against the mycelia growth were determined. The replicated plates were incubated for 5 days at 27±2C. The results showed that the extracts had fungitoxic components that retarded the mycelia growth and of course the disease incidence The mean percentage inhibition of mycelia growth was highest in plates containing extract of pawpaw leaves at various concentrations tested, with the mean percentage inhibition value significantly (P#0.05) higher than in plates containing extract of neem. The inhibitory action of the extracts on mycelia growth increased with increase in concentration.