ANTAGONISTIC POTENTIALS OF SELECTED SOIL FUNGI AGAINST THREE PATHOGENIC FUNGI OF TAGETES ERECTA L. AND T. PATULA L.1

Abstract

Three antagonistic fungi were isolated from the field soil of blight infected
Tagetes spp. by serial dilution method. The fungi were identified as Aspergillus
flavus Link, A. niger van Tiegh. and Trichoderma viride Pers. Antagonistic potentiality
of aforesaid fungi were evaluated against the pathogenic fungi of Tageteserecta
L. and T. patula L. following "dual culture colony interaction" and volatile
and nonvolatile metabolites. The pathogenic fungi were A. alternata, Aspergillus
fumigatus and Curvularia lunata. In dual culture colony interaction, out of three
soil fungi, T. viride showed the highest growth inhibition on A. alternata (71.03%),
A. fumigatus (38.49%) and C. lunata (60.71%). The maximum inhibition of radial
growth of A. alternata (74.55%) was observed with the culture filtrates of T. viride
owing to volatile metabolites. The maximum inhibition of radial growth of A.
fumigatus (37.43%) was observed with the culture filtrates of A. flavus owing to
volatile metabolites. The complete inhibition of radial growth of C. lunata was
observed with the culture filtrates of A. niger owing to volatile metabolites. The
complete inhibition of radial growth of A. alternata was observed with nonvolatile
metabolites of A. nigera and T. viride at all concentrations. The complete inhibition
of radial growth of A. fumigatus was also observed with nonvolatile metabolites
of A. niger at all concentrations. Aspergillus niger and T. viride may be exploited
commercially as a biocontrol agent against blight pathogens of T. erecta and T.
patula.