UNITED STATES OF AMERICA, APPELLEE, v. PRO-AG, INC.; SPENCER W. LANDSWERK, APPELLANTS. No. 91-3313.United States Court of Appeals, Eighth Circuit.Submitted June 8, 1992. Decided July 1, 1992. Page 682 Paul A. Sortland, Minneapolis, Minn., argued, for appellants. Denise M. Zavagno, F.D.A., Rockville, Md., argued, Mary J. Atmore, Asst. U.S. Atty., Minneapolis, Minn., appeared on brief, […]