Lowell DeWitt Ashby, 89, an economist who retired from the Department of Commerce in 1981, died of pneumonia March 3 at Virginia Hospital Center in Arlington. He lived in Arlington. Dr. Ashby joined the staff at the Commerce Department in 1962. From 1948 to 1962, he served on the economics faculty at the University of North Carolina at Chapel Hill. He was born in Hastings, Neb., and graduated from Hastings College. He received a master's degree in economics from the University of Minnesota and a doctorate in economics from the University of Wisconsin. During World War II, he was a Navy communications officer in North Africa, Italy and France. In 1966, he received the Department of Commerce's Silver Medal for "advancing the concepts and techniques of regional economic research." He was a past president and fellow of the Southern Regional Science Association. In retirement, Dr. Ashby was financial partner of the Potomac Investment Club, which he organized in 1969. He was an accomplished water color artist and a member of the Cosmos Club. Survivors include his wife of 61 years, Fern E. Ashby of Arlington; two children, Genette Ashby-Beach of Atlanta and L. DeWitt Ashby Jr. of Vienna; and three grandchildren.