(AP) - Officials in southern Idaho say a 76-year-old farmer has died after being run over by a tractor.     Cassia County officials say Roscoe Ward of Almo started the tractor while it was in gear Wednesday morning and was dragged and eventually run over by the machinery.  Joyce Ward told investigators her husband was working with their grandson-in-law and farm hand Bryan Wallace to bring hay out of a field at the time of the accident. She said he always used a screwdriver to cross the tractor's starter posts to start the tractor while it was in gear. Wallace said he had to pull Ward out of the way of the back tire a few days earlier, when Ward started the tractor the same way.