Allelopathic potential of leguminous plant species towards Parthenium hysterophorus L.
An investigation was undertaken to identify legumes in the local flora that are allelopathic towards Parthenium and can be exploited for obtaining cost effective, ecofriendly and biodegradable herbicides for effective biocontrol/management of this serious weed. Fourteen legumes were tested. 100% aqueous leachates of all the legumes except Pithecellobium dulce, decreased the Seed Germination (SG) and Vigour Index (VI) of the seedlings significantly. The allelopathic influence on SG and VI was most marked from the leachates of Delonix regia (-83.01 and -87.06), Cassia occidentalis (-75.77 and -78.22%), Albizia procera (-67.24 and -85.22%), Tephrosia purpurea (-53.20 and -66.63%) and Moringa indica (-47.44 and -60.09%). All the aqueous extracts studied had inhibitory effects. 100% extracts of Cassia occidentalis (absolute inhibition), Tephrosia purpurea (-88.30 and -93.82%). Trifolium alexandrinum (-87.79 and -90.43%), Delonix regia (-79.26 and -82.45%) Moringa indica (-74.37 and -84.41%), Albizia procera (-73.45 and -89.11%), Bauhinia variegata (-61.82 and -69.22%) and Prosopis cineraria (-55.76 and -65.42%) showed significant inhibition of SG and VI of the seedlings. It is concluded that even the crude aqueous foliar leachates and extracts of the above mentioned plant species could be exploited as herbicides for effective low cost management of Parthenium hysterophorus without any danger of pollution.