Allelopathic Effect of Methanol Extract of Parthenium Plant Parts on Seed Germination and Seedling Growth of Digitaria sanguinalis L. and Eleusine indica L.

For sustainable weed management, herbicides produced from natural ingredients could be an excellent environmentally acceptable alterna-tive to synthetic chemical herbicides. This study looked at the alle-lopathic effects of methanol extract of Parthenium hysterophorus stem, leaf, and flower on seed germination and seedling growth of two weed species, crabgrass (Digitaria sanguinalis L.) and goosegrass (Eleusine indica L.). Five different concentrations of the extract (0, 25, 50, 75, 100, and 150 g L-1) were compared. Percent inhibition in seed germination, root and shoot growth were calculated and EC50 (concentration required to cause 50% growth inhibition) of test weeds were measured. The extracts affected the seed sprouting and seedling growth of test weed species significantly. Leaf and flower extracts were found more phytotoxic than the stem extract. An amount of 50 g L-1 of plant mass was enough to suppress effectively all parameters of the test weed species (designated as EC50). The leaf and flower of Parthenium hysterophorus might contain a number of plant inhibitors or phytotoxins, which could be exploited in future to create a natural herbicide.