Articles

Hemerocallis (Daylily) Diseases

Informational table showing disease name, symptoms, pathogen/cause, and management of Hemerocallis (Daylily) diseases.

Updated:

November 15, 2023

Disease	Symptoms	Pathogen/Cause	Management
Colletotrichum leaf spot or leaf scorch	Leaf tissue dies in a streak along the mid-vein.	Colletotrichum dematium	Remove infected leaves. Destroy leaf debris at the end of the season. Avoid overhead irrigation.
Leaf streak or Red leaf streak	Reddish flecks form on the leaves as the mid-vein yellows. Oval dead spots form and the leaves die prematurely. During wet conditions wet, shiny masses of white spores can be seen with a hand lens on the brown leaves.	Aureobasidium microstictum	Remove infected leaves. Destroy leaf debris at the end of the season. Avoid overhead irrigation. Cultivars vary greatly in susceptibility. Apply a fungicide to protect plants.
Rhizoctonia crown rot	Slender, grassy foliage develops and few flower stalks form. Crowns rot and die.	Rhizoctonia, usually following freeze injury	Protect crowns from freezing.
Russet spot	Reddish spots form on the leaves.	Unknown
Rust	Bright yellow spots or streaks on the upper side of the leaf have bright yellow-orange spores on the underside.	Puccinia hemerocallidis	This fungus also occurs on Patrinia spp. (and possibly Hosta, but this has not been observed in the U. S.). Most cultivars are susceptible. Remove infected leaves and immediately place them in a plastic bag for disposal. Keep the bag closed. Apply a fungicide to protect plants.