Lasiodiplodia theobromae: The causal agent of root rot and collar rot of biofuel plant (Jatropha curcas) and its variability

This is the first report of Lasiodiplodia theobromae (Pat.) griffon & Maubl causing root rot and collar rot disease of Jatropha (Jatropha curcas l.) in gujarat. The symptoms of disease observed were yellowing, drooping and shedding of leaves, blackening and decaying of the collar region of the stem and rotting of the roots. The pure culture of pathogen was obtained and identified as Lasiodiplodia theobromae. The morphological studies revealed that the causal agent (L. theobromae) produced fluffy, aerial dirty white to greyish black septate mycelial growth with abundant pycnidia. The mycelial growth of fungus isolated was classified as fluffy or depressed, uniform to irregular and cottony white turning to black. Colony growth rate varied from 19.1 to 24.9 mm per day. Pycnidia were produced either on the edge, centered or scattered on Petri dishes after 20 to 34 days of incubation.