Selection of mycoherbicidal potential of Fusarium spp. Against a Noxious Weed Parthenium hysterophorus

Microbes and their secondary metabolites offer a benign and eco-friendly alternative to manage weed. Mycoherbicide production for biological control of weeds requires a series steps, from selection of a suitable microbial strain to final formulation. Thus, this study aimed to select potential fungi for production of secondary metabolites with herbicidal activity for control of Parthenium weed. In the present study, phytopathogenic fungi namely Fusarium spp. were isolated from infected tissues of Parthenium and evaluated against Parthenium hysterophorus, a problematic monocotyledonous weed of open lands, Agriculture, Horticulture and Forests. Herbicidal potential of Cell Free Culture Filtrate (CFCF) of three strains of Fusarium spp. coded as FGCCW#16, FGCCW#43 and FGCCW#55, against Parthenium hysterophorus were evaluated by seedling and shoot cut bioassays.  Maximum mortalities of shoots, seedlings and phytotoxic damage were obtained from 21 days old cell free culture filtrate (CFCF) of FGCCW#16 at 100% concentration. Significant reduction in biological contents i.e. photosynthetic pigment and protein was observed in the host weed on treatment with the CFCF as determined by detached leaf bioassay. Phytotoxic damage such as severe wilting, chlorosis, necrosis and complete collapse of the entire parts of the weed were also noticed due to CFCF application.