Evaluation of phytotoxic potential in Asteraceae plant extracts for biological control of and .

This study evaluates the phytotoxic potential of methanolic extracts from six Asteraceae species: , , , , , . The extracts were tested at concentrations of 0.03, 0.1, 0.3, and 1.0 g/mL to assess their inhibitory effects on the radicle and hypocotyl lengths of and . The two most potent species, and , were further evaluated using extracts from their roots, stems, and leaves. Among these, leaf extracts showed the most significant phytotoxicity and were tested at 20, 40, and 60 days of plant age. At 0.03 g/mL, extract inhibited the hypocotyl and radicle lengths of by 23.01% and 56.45%, and by 8.5% and 36.35%, respectively. At 1.0 g/mL, the extract inhibited the hypocotyl lengths of and by 97.54% and 88.15%, and the radicle lengths by 93.52% and 99.99%, respectively. The 60-day-old leaf extract exhibited the highest inhibitory effect, correlating with the identification of key allelochemicals such as cinnamic acid, caffeic acid, coumaric acid, ferulic acid, 2-4 dimethohydroxy benzoic acid, and salicylic acid. These findings suggest that the 60-day-old leaf extracts have strong potential for use in the biological control of these weed species, offering a promising avenue for the development of natural herbicides.