University of Illinois Extension

University of Illinois Extension

Hort Answers

Fungal Disease

Anthracnose [Annuals and Perennials]
Many genus and species involved

Anthracnose on lily of the valley.
Anthracnose on lily of the valley.
3 (1 = rare 5 = annual)
3 (1 = very little damage 5 = plants killed)
Convallaria sp. (Lily-of-the-Valley), Hemerocallis sp. (Daylily), Heuchera sp. (Coral Bells), Hosta sp., Paeona sp. (Peony) as well as many other flowers.

Plants Affected
Anthracnose causes small brown spots on coral bells. Anthracnose causes lesions that are often oval in shape and dark brown in color with purplish margins on Lily-of-the-Valley. These spots may fall out, exposing the veins. This disease is not usually fatal but does weaken the plant. The following year, the number of flowers is often reduced. Anthracnose cause brown spots on the leaves that can merge to form irrugular dead areas and occurs more often on hostas in wet or over watered locations. The brown lesions may spread to encompass the entire leaf. Peony get botrytis and anthracnose. The disease causes buds, flowers, leaves, and stems to die. The disease often cause similar damage to Botrytis on peonies. Culturing is usually necessary for proper identification. Symtoms will vary from plant to plant or even on the same plant depending on pathogen, host, time of infection, weather and so on.

Life Cycle
The disease over-winters on dead plant material and spores can blow for many miles. Wet conditions promote infection and spread of the disease.

Grow Plants in full sun and provide good air circulation. Fungicides and sanitation may be helpful.

Related Resources
Home, Yard & Garden Pest Guide
Illinois Commercial Landscape and Turfgrass Pest Management Handbook
U of IL - Distance Diagnosis through Digital Imaging
U of IL - Plant Clinic