Herbicidal Activity of Baccharis trimera Extract on Oryza sativa L. and Cyperus ferax

This study evaluated the application of the aqueous extract from Baccharis trimera (Less) DC. in the control of weed species Oryza sativa L. and Cyperus ferax Rich. during the germination and early development stages. Extracts were obtained through pressurized liquid extraction using kinetic assays. Shorter extraction times (1 to 10 min) showed extracts with higher inhibitory effects on seed germination, shoot and root lengths, and fresh and dry mass of the plants. The survival of treated plants was also affected, especially during the early stages of development, reaching up to 40% of mortality. HPLC analysis identified phenolic compounds such as ferulic acid, rutin, quercitrin, and quercetin, with higher concentrations found in the extracts obtained at shorter times of extraction. The reduction in these compounds over longer extraction times was correlated with decreased inhibitory activity. The results indicate that the aqueous extract of B. trimera (Less) DC. holds potential for ecological weed management, standing out as a viable alternative to reduce weed resistance to synthetic herbicides.