Abstract: Flexible diffuse-reflective smart camber (FDRSC) devices are disclosed herein. The devices include UV-C lights sources and an irradiance chamber. The irradiance chamber is open on at least one end through which the plants to be treated are exposed to the UV-C irradiance. Further, the inner surfaces of the irradiance chamber are covered by or consist of a diffuse reflective material that passively intensifies and uniformly distributes the UV-C irradiance to penetrate plant canopies. Also described herein are autonomous vehicles for moving the FDRSC devices across fields of crops and other plants. which is controlled in real time by a dosing control system. Also described herein are methods of in-situ UV-C treatment of plants using the FDRSC devices.