The present invention refers to a support device, or hook, for removably securing movable wires on a row of plants, such as for example a vineyard or an orchard, on a support pole. In particular, said support device is made up of an elastically deformable filiform body (1), shaped in such a manner as to have at least engagement elements (2) adapted to elastically cooperate with an opening provided on said support pole (10) to removably secure said support device on said support pole (10), and support elements (3), adapted to elastically cooperate with the external surface of said support pole (10) to removably receive said wire (F), wherein said engagement elements (2) and said support elements (3) are formed by portions of said filiform body (1) lying on planes (P1, P2) essentially orthogonal to each other.