BIOCONTROL POTENTIAL OF ENDOPHYTIC Aspergillus spp. AGAINST Fusarium verticillioides

The soil-borne fungus Fusarium verticillioides is the causal agent of ear, stalk and root rot of maize resulting in severe reduction in yields and quality of infected products. Endophytic fungi have been reported as potential candidates in controlling pathogens since they are considered strong plant mutualists that confer disease resilience to their host. The present study was carried out to determine the in vitro antagonistic activity and biocontrol potential of endophytic Aspergillus spp. associated with Plectranthus amboinicus leaves against F. verticillioides. Three fungal endophytes from the genus Aspergillus, namely; A. tamarii, A. terreus and A. niger were isolated and identified from the leaves of P. amboinicus,. The fungal isolates were tested for their antagonism against F. verticillioides in dual culture plates. Results indicated that the Aspergillus endophytes can restrict the growth of F. verticillioides through varying mechanisms of antagonism. A. niger inhibited F. verticillioides by 47.37%, followed by A. tamarii (41.02%) and A. terreus (27.91%). Dual culture observations revealed that A. tamarii and A. niger antagonized the growth of F. verticillioides via overgrowth mechanism while A. terreus employed antibiosis to restrict the pathogen. These varying degrees of antagonism by the Aspergillus endophytes exhibited their potential as biocontrol agents and source of bioactive compounds.