John A. Ditz; Co-Founder of Construction Firm

John A. Ditz, 70, one of three principals in the construction firm of Ditz-Crane, credited with constructing more than 20,000 houses in the Western states. He began as a tractor dealer with his brother in San Jose, and as the Santa Clara Valley shifted from an agricultural to an industrial economy he moved into home building. In 1970, Ditz-Crane merged with San Francisco-based Foremost-McKesson Corp., with Ditz becoming a vice president and then a division president. He retired in 1985. He was a former trustee of his alma mater, Stanford University, and at his death a trustee of the Palo Alto Medical Foundation. At his vacation home in Sun Valley, Ida., on Saturday of cancer.