Evaluation of plant products and antagonistic microbes against grey blight (Pestalotiopsis theae), a devastating pathogen of tea

The present study was carried out to evaluate the effect of different oils (lemongrass, neem, karanj, zinger, eucalyptus and patchouli oils), different plant product extracts (garlic, zinger, false ashoka and datura) and different antagonistic microorganisms (different species of Trichoderma spp., Bacillus sp. and Pseudomonas sp.) on grey blight of tea, Pestalotiopsis theae. Results reveal that eucalyptus oil and neem oil (0.05%) showed 98.1 and 94.3% inhibition of mycelial growth over the control, respectively. Although, both of them at 0.1% showed 100% inhibition for the pathogen. Similarly, plant extract garlic and datura showed 98.2 and 95.4% inhibition of mycelial growth over control. Among the different antagonistic agents, Trichoderma viride showed 74.3% inhibition of mycellial growth over the control. Among chemical fungicide, bavistin showed 100% inhibition over control. The various antifungal extracts showed inhibitory/fungicidal effect against grey blight of tea. These could serve as sources for development of new antifungal agent. Key words: Plant products, antagonistic microorganism, grey blight of tea, mycelial growth.