Eldon W. Lyle was an American phytopathologist. He specialized in diseases of roses.
In 1937, Lyle began to study how to control black spot disease. During his research, he found that main source of black spot spores is from lesions on its canes, and not the leaflets. He also found that when spraying for black spot that if all the woody parts of the plant were wetted on a weekly basis, good results occur. Lyle also helped in breeding roses, investigated hybrids, genetic composition of roses, cultural adaptation, and the best types of fertilizers to use with roses.