Journal of Research in Weed Science

Abstract Parthenium hysterophorus weeds are one of the major problems in almost all types of agricultural lands, forest lands, pastures, farmlands and disturbed land including roadsides. It is also responsible for health problems in human and animals besides loss to agriculture and ecosystems. It causes allergic respiratory problems, contact dermatitis and mutagenicity. The main strategy of Parthenium control is the use of chemical herbicides. The increasing side effects of chemical herbicide and growing resistance against them in weeds have attracted the attention of researchers to search for some novel herbicidal compounds from natural sources. A significant barrier in the mycoherbicide metabolites production is the development of an economically viable fermentation process. The production of these compounds is largely affected by certain parameters like pH, temperature, incubation days and media constituents etc. Adjustment of these parameters up to optimum level leads to maximum production of mycoherbicidal compounds. Therefore, the purpose of this study was to standardize physiochemical conditions (Nutrient media, pH, Temperature, and Incubation periods) for maximum production of mycoherbicidal metabolites from phytopathogenic fungi Fusarium sp. FGCCW#16 isolated from Parthenium hysterophorus weed. Fusarium sp FGCCW#16 grew well and produced optimum mycoherbicidal metabolites in Richard’s broth medium at 25 to 28°C on the 21 studay of the incubation. The optimal growth, however, was obtained at pH 6. The results of this investigation indicated that cultural conditions like culture media as well as physical factors such as temperature, pH and incubation period greatly affected the growth and production of mycoherbicidal metabolites by Fusarium sp FGCCW#16.

Abstract 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.