Sphynolactone-7 (SPL7) acts as an agonist for the Striga hyposensitive to light receptor 7 (ShHTL7) found in the parasitic plant Striga hermonthica. SPL7 selectively targets ShHTL7 with an IC50 of 0.31 µM, demonstrating higher specificity compared to ShHTL2-6, ShHTL9-10, and the strigolactone receptor AtD14 at a concentration of 10 µM, though it still inhibits ShHTL8 and ShHTL11 with IC50s of 1.2 and 7.8 µM, respectively. This compound triggers fatal germination of Striga hermonthica seeds in the absence of a host by inducing suicidal germination at a minimum effective concentration of 10 fM. Additionally, SPL7 can reduce the emergence of this obligate parasite from the soil and alleviate Striga hermonthica-induced senescence in maize when applied at a 10 nM concentration to the soil of maize and Striga hermonthica seed co-cultures.