In Vitro Antagonism of Trichoderma viride against Five Phytopathogens

摘要

Fungal diseases are of concern in forest regeneration as they occasionally pose a serious threat causing considerable mortality in nurseries. Seedlings are generally susceptible to diseases due to the tenderness of their tissues and are often difficult to establish. The use of biocontrol agents is an important alternative to conventional chemicals in the protection of crops against weeds, insects, and diseases in both agriculture and forestry. The success of biocontrol and increase in the yield depends on the nature of antagonistic properties and the mechanisms of action acquired by the organisms used. Both fungi and bacteria are able to synthesise a wide range of metabolites with fungicidal and bactericidal ability. In this study, Trichoderma viride, evaluated under laboratory conditions against some common phyto-pathogens belonging to different groups of fungi, effectively inhibited the growth of the tested pathogens in dual cultures by hyperpara-sitism and by secretion of volatile and non-volatile metabolites. In the dual culture experiment, maximum inhibition was recorded for Fusarium oxysporum followed by Rhizoctonia solani and least for Alternaria zinniae. The volatile metabolites of T. viride were most effective against F. oxysporum and least effective against R. solani; an almost reverse situation was observed when non-volatile metabolites were examined.