Gather and destroy infected leaves. No chemical control is listed for this disease caused by Cercospora hemerocallis. Russet spot causes greenish yellow leaf spots which gradually enlarge and turn orange-brown.
Plants growing in partial shade seem less affected.
The disease is most common on H. fulva rosea and its varieties. The cause is not known. 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.