Background <p>Plant-derived natural compounds have recently emerged as safer, eco-friendly alternatives to control sand flies. This study investigates the adulticidal effects of <i>Delphinium speciosum</i> extract and <i>Trachyspermum ammi</i> essential oil on the primary vectors of cutaneous leishmaniasis.</p> Methods <p><i>D. speciosum</i> aerial parts were Soxhlet-extracted, and <i>T. ammi</i> essential oil was hydro-distilled, with both processed into various concentrations for bioassay. Sand flies were reared in the Phlebotomine insectary. We used modified WHO Standard Holding Tubes for mosquito susceptibility tests. Concentrations of 50, 100, 200, and 400 mg/mL of <i>D. speciosum</i> extract in ethanol and 2.5, 5, 10, and 20 mg/mL of <i>T. ammi</i> essential oil in methanol were tested.</p> Results <p>Both species showed dose-dependent mortality, with LD₅₀ and LD₉₀ values indicating higher efficacy of the essential oil compared to the plant extract. Linear regression analysis also showed that there was a good correlation between the dose and response, where increased concentration of the treatment led to increased mortality. Additionally, KT₅₀ and KT₉₀ analyses highlighted the rapid action of essential oils, which acted faster on <i>Ph. papatasi</i> than on <i>Ph. sergenti.</i></p> Conclusion <p><i>T. ammi</i> essential oils were effective against <i>Ph. papatasi</i> and <i>Ph. sergenti</i> with a high mortality rate and dose dependent manner. These findings support the use of these natural compounds for sand fly control in leishmaniasis management.</p> Graphical abstract <p></p>