Allelopathic potential of the weed, Parthenium hysterophorus L., in Australia

Stephen W. Adkins and Mark S. Sowerby, Department of Agriculture, The University of Queensland, St. Lucia, Queensland 4072, Australia.


The effect of aqueous leachates of parthenium weed (Parthenium hysterophorus L.) leaves on germination and seedling growth of five test species was examined. Germination of climbing buckwheat (Polygonum convolvulus L.), liverseed grass (Urochloa panicoides Beauv.), buffel grass (Cenchrus ciliaris L.) and parthenium weed were significantly (P <0.05) depressed (92, 95, 88 and 80% respectively) at the highest leachate concentration used (250 mg fresh leaf material mL-1) while the lowest concentration (63 mg fresh leaf material mL-1) significantly (P <0.05) depressed germination of climbing buckwheat, liverseed grass and buffel grass (80, 80, 87% respectively) but not parthenium weed.

Neither high nor low leachate concentrations significantly reduced the germination of sunflower (Helianthus annus L.). Seedling growth, as measured by biomass production of sunflower, liverseed grass, climbing buckwheat and buffel grass were all significantly (P <0.05) depressed (22, 65, 26 and 76% respectively) at a medium leachate concentration (125 mg fresh leaf material mL-1), while a slight stimulatory effect was observed on parthenium weed. The most sensitive species to the leachate applied at the seedling stage was buffel grass which exhibited significant (P <0.05) reductions in shoot and root biomass as well as plant height.


Plant Protection Quarterly (1996) 11 (1) 20-23.