P&PDL Logo

P&PDL Picture of the Week

Southern Blight of Hosta

Gail Ruhl, Plant Disease Diagnostician, Purdue University

The cream-colored structures at the base of the rotted Hosta leaf are fungal "fruiting" bodies known as sclerotia. The basal rot, ropy or fan-shaped white mycelium, and the presence of sclerotia are diagnostic for this destructive fungal disease known as Southern Blight (causal organism: Sclerotium rolfsii). This soil-borne fungal pathogen is an aggressive stem rotter of a wide range of species, including not only flowers and vegetables, but also some field crops and fruit trees. It is favored by high temperatures and high humidity. Controlling Southern Blight is difficult because the pathogen has a wide host range and because the sclerotia persist in the soil.

It is important to avoid moving soil from the affected area to other areas of the garden since sclerotia can be moved with the soil. Infected plants and surrounding soil should be removed. Replace with species not reported to be susceptible to the disease. Some plants from which you can choose include Abutilon, hyacinth, Alyssum, bells of Ireland, lavender, Cleome, Mertensia, cockscomb, Portulaca, four o'clock, primrose, English daisy, statice, Fritillaria, tansy, globe amaranth, Freesia, Gypsophila, and Geranium (wild geranium).

Click on the small image to view a larger image.

Southern Blight of Hosta Southern Blight of Hosta

Southern Blight of Hosta
(Photos by Amy Thompson, Brown County CES)

Top of page. | Current Picture of the Week | Past P&PDL Pictures of the Week

|P&PDL Home Page |

Last updated: 19 June 2002/tlm.
The Plant & Pest Diagnostic Laboratory at Purdue University.