Abstract

Trichoderma (Hypocreales) with promising biocontrol and plant growth promoting activities acts upon the phytopathogens by adopting multifaceted tactics and induction of plant defense responses. Trichoderma species having biocontrol potential are often armed with a treasure house of low molecular weight secondary metabolites which help in its antagonistic properties via mycoparasitism, antibiosis, competition and by induction of plant defense responses. Broadly, the secondary metabolites are classified into two groups viz., volatile organic compounds (VOCs) and non-volatile organic compounds. The VOCs produced by Trichoderma are either gas-phase and/ or carbon-based molecules of both low and high molecular weight with antifungal, antibacterial, nematicidal effects as well as exhibit plant growth promoting properties. VOCs of Trichoderma leads to hyphal abnormalities in the phytopathogen such as deformation, swelling/ shrinkage, lysis as well as change in hyphal pigmentation. This chapter attempts at a brief explanation on use and scope of VOCs released by Trichoderma species in plant health management.