Utilization of Parthenium hysterophorus Aqueous Extracts as a Bio-Herbicide - An Alternative for Synthetic Herbicides

Invasive weed Parthenium hysterophorus has been wreaking havoc all over the terrestrial ecosystems in tropics and sub-tropics. The traits governing successive invasion and colonization of this weed are superficial seed production ability, inedibility to animals and allelopathy. Allelopathy refers to the impact of plants on nearby plants or their associated microflora or macrofauna by the production and release of allelochemicals. The identification and characterization of allelochemicals will be helpful for utilizing in agricultural pest management operations. In this rationale, a preliminary probe has been made to assess the potential of Parthenium hysterophorus aqueous extracts as a farmer friendly herbicide. Raddish seeds have been used to test the phytotoxicity of the extracts and complete germination inhibition was found with application of 25% extract. Seeds in control has a germination speed of 5.29 seeds germinated/day and produced robust seedlings with 4.81 cm shoot and 2.87 cm, whereas application of 20% aqueous extracts has reduced the germination speed to 0.17 seeds germinated/day with nil seedling formation. On working out phytotoxicity percentage, it is revealed that 10% extract application has produced 100% phytotoxicity. Interestingly, the phytochemical analysis of the Parthenium hysterophorus aqueous extracts by GC-MS has revealed the presence of 4 phytotoxins viz., 1-Tetradecene, 2-methyldodecane, Eicosane and 1-Decanol, 2-hexyl-.