Freeman, former governor of Minnesota, became Secretary of Agriculture in the Kennedy administration in 1961. (He just appeared on the cover of Time magazine, April 5, 1963).
Be sure to review Chaps. 1,2,7,10,15,17 of Silent Spring (see also index for 'USDA'). You should be able to comment on benefits of pesticides, safety (to consumers and workers) and indiscriminate use, and especially on alternatives. You may wish to comment on the USDA's programs to control gypsy moths, fire ants and Japanese beetles (Chaps. 10,15).
Graham, Since Silent Spring
"Rachel Carson's Silent Spring," CBS Reports [audio recording]. See Guide.
Murphy, What a Book Can Do, pp. 90-93.
United States Department of Agriculture (1957-1965). Report of the Secretary of Agriculture, Washington, D.C.
Agricultural Yearbook, 1952 [data on insects]
of possible interest & for further background [Note it is after 1963]: Freeman, Orville. 1968. World Without Hunger. New York: Frederick A. Praeger.
Lear, Linda. 1992. "Bombshell in Beltsville: The USDA and the Challenge of Silent Spring," Agricultural History 66:151-170