The highly invasive weed Chromolaena odorata (L.) R.M. King & H. Rob. is widely recognized for its strong allelopathic and competitive influence within agricultural ecosystems. The present study evaluated the antagonistic effects of C. odorata on the growth performance of three economically important crops, such as rice (Oryza sativa L.), moong dal (Vigna radiata L.), and sunflower (Helianthus annuus L.), when grown in close association with the weed. Comparative growth assessments were conducted between crops cultivated in the presence and absence of C. odorata in the laboratory. The results revealed a significant suppression of crop growth attributable to antagonistic interactions imposed by the weed. Among the crops studied, moong dal exhibited the highest sensitivity, showing a 22% reduction in growth, followed by rice, which recorded a 15% decrease in overall growth. In sunflowers, reproductive development was markedly affected, as evidenced by an 18% reduction in head size compared with control plants. The observed growth inhibition is likely associated with the allelopathic potential of C. odorata, mediated through the release of phytotoxic compounds via root exudates and decomposing plant residues. These allelochemicals may disrupt normal physiological and developmental processes in neighbouring crop plants. The findings highlight the ecological dominance of C. odorata and its capacity to adversely affect crop productivity in agroecosystems. A clear understanding of such crop–weed antagonistic interactions is essential for devising effective weed management strategies aimed at reducing yield losses and supporting sustainable agricultural practices.

Chromolaena odorata, Allelopathy, Crop-weed Interaction, Growth Inhibition