Potential of Vochysia divergens extracts as a post-emergence bioherbicide

The genus Vochysia, particularly Vochysia divergens Pohl, has been studied for its diverse biological activities and phytochemical composition. This study investigates the phytotoxic potential of V. divergens extracts as bioherbicides, with emphasis on their effects on photosystem II (PSII) and weed growth. Methanolic and hexane extracts from leaves, flowers, and stems were prepared and evaluated in semi in vivo and in vivo assays against the weeds Senna alata and Sida rhombifolia. Chlorophyll a fluorescence analysis revealed that both methanolic and hexane stem extracts (VMS and VHS) significantly reduced PSII efficiency and performance indices. These effects were associated with inhibition of the electron transport chain, suppression of photochemical reactions, and a reduction in the number of active PSII reaction centers. In vivo assays further confirmed the phytotoxic effects, with the VMS extract at 300 ppm reducing the photosynthetic capacity of S. rhombifolia by 46% and plant growth by 87%. These results highlight the potential of V. divergens stem extracts as eco-friendly bioherbicides eco-friendly bioherbicides and support their use as sustainable alternatives to synthetic herbicides.