A comprehensive mycofloral diversity of pedosphere, phyllosphere and aerosphere of Som. (Persea bombycina Kost.) in lower Brahmaputra valley of Assam

摘要

Muga silkworm is endemic to North-East India. The quality of primary host plant, i.e. Som. (Persea bombycina Kost.), greatly affects the quality of cocoon and silk production. Som is susceptible to different foliar diseases caused by fungi, which can reduce the yield of leaf from 13.8 to 41.6% annually. So, a comprehensive mycofloral study of the host plant is important to forecast future diseases and design different disease management procedures. This study has been done for a period of 2 years from 2014 to 2016 in Goalpara district of Assam, India. Mycoflora of pedosphere (rhizosphere and non-rhizosphere), phyllosphere and aerosphere were identified and correlated with the seasonal variation. The rhizosphere, air and phylloplane were dominated by Rhizopus stolonifer (22.13%; 15.08%; 24.01%), while Aspergillus niger (12.63%) dominated non-rhizospheric soil. In summer, soil was majorly dominated by A. niger, Aspergillus fumigatus and Curvularia lunata, while R. stolonifer, Aspergillus clavatus and Penicillium chrysogenum dominated the winter soil. Pestalotiopsis disseminata is one of the major pathogens of Som and was found highest in aerosphere followed by phyllosphere. Temperature between 25 and 28 degrees C with 70-80% of relative humidity favours P. disseminata. This study provides a deep insight into the fungal diversity of Som with respect to pedosphere, aerosphere and phyllosphere, and this knowledge can be used to better select the plantation area and design different disease management strategies to sustain and proliferate the industry for socioeconomic development and to conserve its cultural essence.