Willard H. Lamphere, 77, a retired information officer with the Department of Agriculture, died of cancer Tuesday at his home in Falls Church. He had been a resident of Northern Virginia for more than 40 years.

Mr. Lamphere was born in Dunnell, Minn. He grew up in Cascade, Mont., attended Montana State College and graduated from the University of Idaho with a degree in agricultural science in 1926. He taught in high school at Lewistown, Mont., until joining the Montana Agricultural Extension Service as a county agent in 1930. Later, he was agricultural information officer for Montana State College and editor of its monthly Agricultural Outlook.

Joining the Agriculture Department here in 1939, Mr. Lamphere was information officer for field administration in the Agricultural Adjustment Administration, a predecessor of the Agricultural Conservation and Stabilization Service where he served until retirement in 1969. He was gone briefly in 1947 to be agricultural representative of the Great Northern railroad in St. Paul, Minn.

Mr. Lamphere, who had received a number of merit awards from the Agriculture Department, specialized in growing dahlias. One of the varieties he originated, Stevie D, was named for his grandson and its grown nationwide. He was a member of the American Dahlia Society and the National Capital Dahlia Society.

After he retired, he worked as a volunteer with the Fairfax County Red Cross and Meals on Wheels. He had been an active member of Rock Spring Congregational Church in Arlington for 37 years.He had helped develop the Fairfax County Girl Scout camp on Aquia Creek.

He is survived by his wife of 54 years, the former Helen Hillsburg, of Falls Church; a daughter, Elizabeth Anne Drab of Huntington, Conn., and two grandchildren.

The family suggests that expressions of sympathy be in the form of contributions to the Hospice of Northern Virginia, Inc.