Dr. Ivan Stewart (1922)

Inducted 1987


Lake Alfred Citrus Research & Education Center

Iron Deficiency

Chelated Iron Mixture

Fertilization & Nutritional Spray Programs

Color Deficiency

Haines City Citrus Growers Association


Ivan Stewart was born in 1922. Not long after entering the University of Kentucky, Stewart cut short his education with the outbreak of World War II. While in the Army he served with the division of chemical warfare in the Pacific Theater. At war’s end Steward returned to the University of Kentucky where he earned a bachelors and masters degree in agronomy. He then attended Rutgers University, earning his Ph.D. in soils and plant physiology. Joining the faculty of the University of Florida, where he worked for 36 years as a biochemist, Stewart also labored at the Citrus Research and Education Center at Lake Alfred. His research at this center would lead to some of the most significant scientific contributions to the Florida citrus industry.

Stewart’s first 10 years of research was primarily focused on the nutrition of trees. He discovered that a major problem with citrus trees was molybdenum deficiency, or iron deficiency. Stewart developed a corrective measure, using a Chelated iron mixture. He also developed methods to accurately measure carotids in citrus and discovered two pigments not known to exist in nature. Stewart also played a major role in developing new fertilization and nutritional spray programs that in many cases reduced citrus production costs by two thirds. He was instrumental in the identification and development of methods to correct certain deficiencies in Florida soil allowing growers to increase fruit production. In color research,

Stewart isolated and identified the major carotenoids in citrus peel and juice. This discovery helped the industry correct naturally the color deficiency associated with fruit grown in a sub-tropical climate.

Stewart is a past president of the Rotary club and served on the board of directors of Haines city citrus growers association. Stewart was also was involved with founding Heart of Florida Hospital and served on its Board of directors. He has been married to his wife Gladys for over 55 years.