Dr. George F. Knowlton, at the USAC Agricultural Experiment Station, holding up two drawings of pea aphids, a common pest of pea, alfalfa and of certain clovers, 1950s. Aphids spread virus diseases of celery, potatoes, beans, and various other farm...
Utah State University -- History -- Pictorial works; Knowlton, George F. -- Portraits; Entomology -- Utah -- Logan -- Pictorial works; Utah State Agricultural College -- History -- Pictorial works; Entomology -- Research -- Utah -- Logan --...