Use basic copper sulfate if needed.
Powdery mildews form a white coating on the leaves.
Spray with benomyl or sulfur. 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. Reprinting cannot be used to endorse or advertise a commercial product or company.