Ageratina adenophora essential oil: A promising miticidal agent against Sarcoptes scabiei, and its effects on key enzymatic pathways

• Ageratina adenophora essential oil shows contact, fumigation & repellent effects against S. scabiei. • Ageratina adenophora essential oil shows therapeutic efficacy against rabbit scabies. • Ageratina adenophora essential oil has no irritating effect on skin. • Ageratina adenophora essential oil’s acaricidal effect involves S. scabiei enzyme modulation. The common scabies mite, Sarcoptes scabiei ( S. scabiei ) is a cosmopolitan parasite of humans and other mammals. This study evaluated the potential of Ageratina adenophora ( A. adenophora ) essential oil (EO) to serve as a synergist for enhancing biological control agents against scabies by investigating its acaricidal activity and underlying mechanism. 52 components (99.6 %) were identified by GC–MS. The major components included bornyl acetate (11.16 %), β -bisabolene (9.34 %), cymene (8.17 %), γ -curcumene (8.10 %), and β -caryophyllene (8.05 %). In vitro , it showed good contact toxicity, fumigation activity, and repellency against S. scabiei . At 40 mg/mL for 2 h, the contact mortality, fumigation mortality and repellent rates were 100 %, 100 %, and 92 %, respectively. Medium lethal concentration (LC 50 ) values for contact toxicity and fumigation activity at 2 h were 27.132 mg/mL and 12.579 mg/mL. In vivo , cure rates at 20, 10, 5 mg/mL were 100 %, 100 %, 83.3 % in rabbits, with no skin irritation at 200 mg/mL. Enzyme tests showed that SOD increased first, then decreased, GST was activated, AchE, Na + -K + -ATP, and Ca 2+ -Mg 2+ -ATP were inhibited. The significant activity of A. adenophora essential oil both in vitro and in vivo , along with its ability to disrupt key physiological processes in mites, supports its potential as a synergist to enhance the efficacy of biological control agents against scabies mites. Additionally, the observed safety profile at certain doses further encourages its exploration as a component within integrated pest management strategies.