This study investigated the allelopathic effects of leaf leachates of invasive weed Ageratum houstonianum Mill. on two crop plants viz. Raphanus sativus L. and Vigna mungo (L.) Hepper in both petri-plates and pots culture. In petri-plates, the leachate had no effect on seed germination of R. sativus. However, in V. mungo, germination was reduced by higher concentrations of leachates. The leachates also reduced root and shoot length and biomass. In pot experiment, shoot and root growth, leaf number and biomass were reduced in both species. The phytotoxic effects of A. houstonianum on both crops suggested that the weed has potential threats to agro-ecosystems where these plants are cultivated. As the allelochemicals responsible for these effects were not identified due to resource limitations, further research should concentrate on identifying the key allelochemicals responsible for the effects on specific plants and on exploring management strategies to mitigate the impact of this invasive species
Wani et al. (Wed,) studied this question.