Sprays of sulfur control rust. Leaf spot causes angular grayish spots scattered over the leaf. The dead tissue falls out giving a shothole effect. Remove and destroy plant residues at the end of the growing season. No chemical control is listed.
Powdery mildew covers the leaves with a white powdery growth.
Applications of benomyl or sulfur control the disease. Visuals associated with this text. This information is for educational purposes only. References to commercial products or trade names does not imply endorsement by MSU Extension or bias against those not mentioned. This information becomes public property upon publication and may be printed verbatim with credit to MSU Extension.