AbstractBackgroundVoltage‐gated potassium channel Kv2 is the primarily delayed rectifier in insect nerves and muscles involved in several crucial biological processes, including action potential regulation, photoreceptor performance, and larval locomotor. It is a potential molecular target for developing a novel pesticide for mosquitos. However, there are few studies on the Kv2 channel in agricultural pests.ResultsThe only α‐subunit gene of the Kv2 channel in Plutella xylostella (L.), PxShab, was cloned, and its expression profile was analyzed. The relative expression level of PxShab was highest in the pupal stage of both sexes and male adults but lowest in female adults. Meanwhile, PxShab had the highest expression in the head in both larvae and adults. Then, PxShab was stably expressed in the HEK‐293 T cell line. Whole cell patch clamp recordings showed an outward current whose current–voltage relationship conformed to a typical delayed‐rectifier potassium channel. 20 μM quinidine could effectively inhibit the potassium current, while the channel was insensitive to 4‐AP even at 10 mM. Several potential compounds and botanical pesticides were assessed, and carvedilol (IC50 = 0.53 μM) and veratrine (IC50 = 2.22 μM) had a good inhibitory effect on the channel.ConclusionThis study revealed the pharmacological properties of PxShab and screened out several high potency inhibitors, which laid the foundation for further functional research of PxShab and provides new insight into designing novel insecticides. © 2022 Society of Chemical Industry.