Antagonistic Activities of Triehoderma harzianum Against Pythium aphanidermatum and Pythium myriotylum on Tobacco

Triehoderma harzianum rendered Pythium aphanidermatum and P. myriotylum non-viable in
Petri dish dual culture. The Pythium mycelia from such cultures showed natural autofluorescence in
the regions of interactions, indicating their death. Non-volatile and volatile fungicidal activities were
detected in T. harzianum culture. LytJc activity of /6-(l,3)-glucanase was detected on the cell walls of
the Pythium spp. There was a significant decrease in the disease incidence when T. harzianum was
incorporated into sterile soil, whereas the effect was insignificant in natural soil.