PHYTOTOXIC AND BIOHERBICIDAL POTENTIAL OF FIVE WILD PLANT EXTRACTS AGAINST EUPHORBIA HETEROPHYLLA L.: EFFECTS ON SEED GERMINATION, PLANT GROWTH AND POLLEN GERMINATION

Abstract

Euphorbia heterophylla is a problematic weed, necessitating the development of effective and sustainable alternatives to conventional weed-management practices. The present study evaluated the phytotoxic potential of aqueous extracts of Achyranthes aspera, Jatropha gossypiifolia, Lantana camara, Leucas aspera, and Mesosphaerum suaveolens against E. heterophylla at different developmental stages. Seed germination and seedling growth were assessed at 3, 6, 9, and 12% extract concentrations, while inhibition of established plants was monitored for 15 days. Pollen germination was evaluated using 2% aqueous extracts. All extracts inhibited seed germination, with stronger inhibition generally observed at higher concentrations. Seed viability was markedly reduced at 9 and 12% concentrations, particularly following treatment with A. aspera, J. gossypiifolia, L. aspera, and M. suaveolens. All extracts caused complete (100%) mortality of established E. heterophylla plants within 10–15 days. Among the extracts, L. aspera showed comparatively strong early activity, producing 62.5–87.5% mortality during days 5–10. Furthermore, all five extracts completely inhibited pollen germination at 2%, compared with 22.72% germination in the untreated control. Overall, the extracts exhibited broad phytotoxic activity against E. heterophylla, affecting seed germination, vegetative growth, survival, and pollen germination. These findings highlight their potential as sources of natural phytotoxic compounds for bioherbicide development and integrated weed management. Further studies are required to identify the active compounds and validate their efficacy, selectivity, and environmental safety under greenhouse and field conditions.