Biological Control Of Rice Disease (Blast) By Using Trichoderma Viride In Laboratory Conditions

The most common biological control agents of the genus Trichoderma have been reported as strains of T. virens, T. harzianum, and T. viride. Since Trichoderma biological control agent use different mechanisms of biocontrol, it is important to explore the synergistic effects expressed by different genotypes for their practical use in agriculture (Hemosa et al., 2000). Trichoderma species have been investigated as biological control agents for over 70 years, but it is only recently that strains have become commercially available. This finding is largely a result of the change in public attitude towards the use of chemical pesticides and fumigants such as methyl bromide. Trichoderma viride is an efficient biocontrol agent that is commercially produced to prevent development of several soil pathogenic fungi. Different mechanisms have been suggested as being responsible for their biocontrol activity, which includes competition for space and nutrients, secretion of chitinolytic enzymes, mycoparasitism and production of inhibitory compounds (Harman et al., 1993). Rice disease blast is caused by Pyricularia oryzae. Blast disease initial symptoms are white to gray-green lesions or spots with darkened borders produced on all parts of shoot; older lesions are elliptical or spindle-shaped and whitish gray with necrotic borders. Lesions are wide in the centre and pointed toward either end; lesions may enlarge and coalesce to kill entire leaves. The objective of this study is to control blast disease in rice. The study is to be conducted in the Faculty of Agriculture and Forestry, University of Guyana, at Berbice Campus, Science Centre, John, from February 2009 to May 2009. The experiments are designed in a completely random block design with three replicates. Parameters to be observed are selection of medium, temperature, pH, and measurement of disease index and disease severity randomly. The studies are to show the potential of T. viride for control of blast disease in rice.