Trichoderma- Foliar Pathogen Interactions

Among the group of ubiquitous soil inhabiting fungi, Trichoderma species are of considerable commercial importance due to their ability to suppress many plant pathogenic fungi. They have been widely studied and employed for management of root and seedling diseases of many crops since decades. In recent years they are also being utilized for minimising diseases of foliar plant parts, especially to supress grey mold caused due to infections of Botrytis cinerea and powdery mildews on a number of crops. They also express potential to control downy mildews and have improved the shelf life of grapes. Out of the eighty-nine species of Trichoderma, a number of species exhibit the bio-control activity. The destruction of host hyphae and protoplasm by the various lytic enzymes and toxic volatile and non-volatile compounds produced by these species are the major mechanism of bio-control; apart from deactivation of pathogen enzymes and induction of systemic resistance in host plants. However, significant differences in antagonistic potential among isolates even from the same species from the same niche is observed; and hence selection of a strain with wide host range and environment adaptability becomes a key issue for sustainable biological control.