James Merrill Wallace was a professor in the department of Plant Pathology at the University of California, Riverside. He was a world renowned expert in citrus virus diseases. Wallace began his long career with UCR at the Citrus Experiment Station in 1942. Prior to that, he worked at the U.S. Department of Agriculture in Twin Falls, Idaho and Riverside, California, at the Office of Sugar Plants, where he was a plant pathologist from 1929 to 1942.

He was born in Ripley, Mississippi on October 13, 1902. He received a B.S. in agriculture from Mississippi State University in 1923. Wallace went on to earn both a M.S. (1927) and Ph.D. (1929) in plant pathology from the University of Minnesota.

Wallace was renowned for his pioneering research in citrus virus diseases. During his tenure at UC Riverside, he discovered, along with Dr. Howard Fawcett, that quick decline, or tristeza disease, was caused by a virus. In addition to publishing numerous articles on citrus diseases, Wallace founded the International Organization of Citrus Virologists (IOCV), an international organization of citrus researchers that includes members in forty-one countries.

Wallace was also an active in the Riverside community. He was a member of the Kiwanis Club of Riverside for over thirty years and served as the club president in 1948.

Wallace passed away in 1979.