Studies on water-soluble compounds extracted from
Trichoderma species, showed that all the Trichoderma
species tested inhibited the growth of C. paradoxa. T.
polysporum exhibited better growth inhibition at high
concentrations than the other Trichoderma species. The
effects of the inhibitory actions on C. paradoxa by T.
viride, T. polysporum and T. hamatum appear to be associated
with toxic volatile compounds produced by them.
The actual effect and mechanism involved is not known,
but Trichoderma spp. are known to produce a range of
metabolites that may affects the growth of microorganisms
and plants (Ghisalberti and Sivasithamparain, 1991).
It was obvious that C. paradoxa was inhibited at high
concentrations of 100% and 70% by T. polysporum and
T. viride but the pathogen growth was stimulated at low
concentrations of 50%, 30% and 10%. The consistence
of T. polysporum, dropped at low concentrations while T.
viride picked up slightly at low concentrations. The reasons
for the average performances of T. hamatum and T.
aureoviride at high concentrations and their poor performances
at low concentrations were not known.