Production of volatile and non-volatile metabolite
Eleven Trichoderma isolates which showed class 1 type
antagonism in dual culture experiments were evaluated for
the production of volatile inhibitory substances in vitro
following the technique of Dennis and Webster (1971a).
Antagonists were grown on Petriplates containing Czapek’s
agar medium for 5, 10 and 15 days. The top of each Petriplate
was replaced with the bottom of another Petriplate containing
agar medium and inoculated centrally with a mycelial plug of
the pathogen. Plates with agar medium without Trichoderma
spp. at the lower lid and plates inoculated with mycelial disc
of the pathogen on the upper lid were maintained as control.
The pair of each two plates were taped together with
cellophane adhesive tape. Radial mycelial growth of the
pathogen was recorded after 72 hr of incubation at 25±10C
and per cent inhibition of mycelial growth was calculated.