The pilot reported that during the landing roll, the tailwheel equipped airplane suddenly veered to the right. Despite his control inputs, the airplane continued to veer to the right and ground looped which resulted in structural damage to the left wingtip and aileron. Examination of the airplane by the pilot revealed that the nicopress fitting on the left rudder control cable had failed, which allowed the cable to become disconnected from the rudder bellcrank. No additional preimpact mechanical malfunctions or failures with the airplane that would have precluded normal operation were reported.