A control system is provided for an implement such as a mower having a rotary blade driven by a gear box which is driven by a PTO shaft of a vehicle which is coupled to the mower. The vehicle has a drivetrain which drives the PTO shaft. The control system includes an acceleration sensor for sensing vibrations of the blade and generating a blade vibration signal. A PTO speed sensor generates a PTO shaft speed signal. A control unit is connected to the sensors and to the drivetrain. The control unit generates, as a function of the speed signal, an expected acceleration value representing a blade loss condition and an expected acceleration value range. The control unit compares the vibration signal to the range, and the control unit stops the drivetrain from rotating the blade if the vibration signal is within the range.
