Inhibition of Fusarium causing death before life in sissoo (Dalbergia sissoo Roxb.)by a botanical-Putranjiva

Abstract

Sissoo or sisham(Dalbergia sissoo Roxb.) is a medium to large-sized deciduous tree.The species occurs throughout the plains in north India,from Punjab to Assam ascending upto 100m in the Himalayas.Due to the value of timber ,sissoo is raised in plantations.During survey at 20 different places of four districts of Eastern U.P it has been found that in a one kilometer area if 100 plants of sisham are growing more than 30 plants has been found wilted.So frequent survey was conducted in order to collect wilted samples from 20 places of Eastern U.P districts.Survey of these places revealed that wilting occurs in all age groups,even in nursery plants,in age group of 10-15 year,15-20 year,30-40 year,during humid months from July to September.In Basti district it was found highly alarming causing 50% wilting in July months followed by Siddharth nagar,Santkabir nagar and Gorakhpur districtThe symptoms observed in all wilted plants were yellowing and death of leaves in acropetal succession and lastly entire plant in yellow appearance.So root samples were collected from wilted plants from these places for study of rhizoplane mycoflora.The root free from rhizosphere soil was cut into small pieces with the help of sterilized scalpel and forceps and plated on the medium and incubated at 20+_2C for 6 days to observe the appearance of fungi.Both sterilized and unsterilized root pieces were observed.In all age group Fusarium solani and Fusarium oxysporum were found to be present in both sterilized and unsterilized root pieces.Seven species of Fusarium isolated from roots were tested for their pathogenicity on sissoo.During pathogenicity testing of Fusarium solani,Fusarium oxysporum it was found that Fusarium solani is highly powerful causing 100% wilting in plants. In nature plants are available which have volatile activity that can destroy fungal pathogens.So far 32 essential oils were extracted from higher plants and tested against Fusarium solani and Fusarium oxysporum.The oil of Putranjiva roxburghii showed complete inhibition of mycelia growth of both test fungi at 500ppm.The oil was thermostable at its mic of 500ppm and exhibited wide range of activity at 1000ppm.Moreover,the fungitoxicity was not destroyed by autoclaving and storage upto 120 days.The oil obtained from Feronia limonia also showed inhibitory activity at 1000ppm.The root and bark extract of Putranjiva was also found to be effective against both species of Fusarium.In this way this plant have overall anti action against Fusarium.So a little mixed field trial at nursery bed level was conducted with Putranjiva which showed no wilting symptoms compared with separately grown control sets of sissoo.So Putranjiva may be used against Fusarium to protect sissoo after successful large scale mixed plantation field trials.