Ethanolic extract effects of B. halimifolia, D. stramonium, and L. hexapetala on selected weed species: germination and root length inhibition

Today a key challenge in farming are weeds that are usually controlled using synthetic herbicides. Yet frequent application brings problems - resistance builds up, ecosystems face problems, increase in production cost. Because of this shift, attention turns toward sustainable alternatives like allelopathy, a natural phenomenon where certain plants release bioactive substances that hinder the growth and development of nearby plant community. This study investigated ethanolic extracts from three plants: Baccharis halimifolia, Datura stramonium and, Ludwigia hexapetala. Their influence was tested on germination and initial development stages of common crop field weeds. From the donor plant, samples were gathered, air-dried, then turned into ethanolic extracts using standardized extraction procedure. These extracts were tested on Abutilon theophrasti, Lolium rigidum, Setaria pumila, Amaranthus retroflexus, Chenopodium album, Digitaria sanguinalis, Echinochloa crus-galli, and Sorghum halepense at different concentrations. Germination assays were conducted under controlled laboratory conditions with distilled water as positive control. Germination percentage and seedling root length were evaluated as indicators of phytotoxic activity. Despite differences in allelopathic response, each donor plant limited weed development depending on the extract concentration and target weed species. Higher doses typically led to greater suppression in germination and root elongation. From the tested species, ethanolic extracts of Datura stramonium showed the most phytotoxic activity, disrupting germination and early growth. This study suggests that secondary metabolites within these plants likely play a role in hindering unwanted vegetation naturally and can play a role in developing sustainable weed management strategies. Identifying exact molecules responsible and optimizing the extraction and application rates remains a key step forward. Field trials will ultimately determine practical usefulness beyond lab settings.