This paper presents an acceleration-command generation and its implementation for an aerial vehicle in the problem of visual target tracking, when the target is free to make any maneuver with arbitrary but otherwise bounded acceleration. The acceleration command is generated by an adaptive disturbance rejection control algorithm that uses only visual information about the target, obtained by a monocular camera mounted on the aerial vehicle. This information consists of the maximal image size in pixels and the pixel coordinates of the image centroid in the image plane. The acceleration command is translated into forward velocity and attitude angle commands, which are afterward used to obtain actual control surface deflections for the aerial vehicle. Simulations of a full nonlinear model verify the theoretical statements.