Daylilies in general

The American Hemerocallis Society
The Daylily Place
National Gardening Association Daylily Forum

Phenology
USA National Phenology Network
Phenology - Wikipedia

Pests
Bulb Mites
Bulb Mites in Ornamentals
Pests Section of AHS Daylily Dictionary
Lesser Bulb Fly

Leaf Streak Fungus (Aureobasidium microstictum)
Leaf Streak
Fungicides for Leaf Streak Study