Is Ruqyah permissible if it involves reciting the Qur'an and supplications for the sick person, along with rotating a grain of wheat over the wart and then burying it, with the intention that the wart will die as the wheat dies, knowing that nothing else is said or requested from the patient, and only a small fee is taken from him?

Ruqyah (definition) with the Quran and supplication is legislated. As for using a grain of wheat in treatment, we do not know of anything that proves its benefit in Islamic law or through experience. We fear that it may be inspired by charlatans. It is obligatory to dispense with it, relying instead on the legislated Ruqyah and medical treatments.