A grapple attachment is equipped with driven rollers for selectively turning a wrapped round module about its axis so as to position it for having the wrapping slit at the bottom side of the module. When the module is properly located for having the wrapping slit, a powered cutting blade is caused to move into engagement with the wrapping and slit it across the length of the module. An interlock is provided for preventing operation of the grapple cylinders and driven roller motors unless the cutting blade assembly is located in a standby position wherein it is removed from a zone normally occupied by the round module when the latter is supported by the fixed and moveable grapple sections of the grapple attachment.