| Disease |
Symptoms |
Pathogen/Cause |
Management |
| Leaf Streak |
Circular to elongated tan to dark-brown
spots with light green halos form on leaves. |
Collecephalus
hemerocalli |
Remove infected leaves. Destroy leaf
debris at the end of the season. Avoid overhead irrigation.
Cultivars vary greatly in susceptibility (see reference below*). |
| Leaf Scorch |
Large dead streaks form down the
center of the leaves from the tips. |
Colletotrichum
dematium |
Remove infected leaves. Destroy leaf
debris at the end of the season. Avoid overhead irrigation.
|
| Red Leaf Streak |
Reddish flecks form on the leaves
as the midvein yellows. Oval dead spots form and the leaves
die prematurely. During wet conditions, 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.
Protect new growth with thiophanate methyl. |
| |
|
|
|
| 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 |
Yellow spots or streaks on the upper
side of the leaves and bright yellow-orange masses of spores
on the underside make this disease easy to diagnose. |
Puccinia
hemerocallidis |
This fugus also occurs on Patrinia
spp. (and is reported to infect hosta, but this has not been
observed in the U.S.). Most daylily cultivars are susceptible.
Remove infected leaves and place them in a tightly sealed bag.
Do not compost infected leaves. Apply azoxystrobin, chlorothalonil,
flutolanil, or mancozeb weekly until the disease is under control. |
