Herbicidal activity and biochemical characteristics of the natural product australol and preparation of an australol‐based emulsifiable concentrate

Abstract BACKGROUND Botanical herbicides play a crucial role in agricultural sustainability and environmental protection. This study elucidated the herbicidal activity and biochemical characteristics of australol, and successfully developed an australol‐based emulsifiable concentrate (EC). The research lays the foundation for the development and application of novel botanical herbicides. RESULTS Australol exhibits significant herbicidal activity, and the inhibition rates of root length and stem length of Echinochloa crusgalli and Amaranthus tricolor were both 100% when the concentration of australol is 1 mg/mL. In the pot experiment, when treated with australol at a concentration of 10 mg/mL for 7 days, the inhibition rates on fresh weight of E. crusgalli , Abutilon theophrasti , and Amaranthus tricolor were 89.50%, 82.69%, and 86.35%, respectively. Australol can destroy the root tip cell morphology and structure of E. crusgalli and Amaranthus tricolor . It can also increase the content of malondialdehyde, and the activity of peroxidase was also significantly increased. When the concentration of 20% australol EC is 10 mg/mL, the fresh weight inhibition rate of Amaranthus tricolor was 100%. When 38% atrazine suspension concentrate (SC) is reduced by 30% and combined with 20% australol EC, the fresh weight inhibition rates of the aboveground parts of E. crusgalli and Amaranthus tricolor are both 100%. CONCLUSION The natural compound australol has a significant inhibitory effect on the growth of weed seedlings by disrupting the root morphology and membrane structure of weeds. An australol‐based EC was prepared, which can achieve the effect of reducing chemical pesticide usage while enhancing efficacy. © 2025 Society of Chemical Industry.