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The P&PDL Picture of the Week
for 6 June 2003



A Fungal Blight on Pachysandra

Gail Ruhl, Interim P&PDL Director, Dept. of Botany and Plant Pathology, Purdue University

Volutella stem and leaf blight is the most devastating fungal disease of Pachysandra. This disease can destroy large areas in a bed. Infected leaves first develop tan or brown blotches with dark brown margins, which expand, often with concentric lighter and darker zones. Stem and stolon cankers can become numerous and plants start to wilt and die. Cankers appear as water-soaked diseased areas, turn brown, shrivel and often girdle the stem. Orangish spore masses develop in the cankered areas and the underside of infected leaves.

Volutella blight of pachysandra is often associated with plant stresses such as recent transplanting, exposure to bright sunlight, shearing, scale insects, and previous winter damage. Normally this disease does little damage to vigorous plants, so providing good growing conditions is the most important control measure.

Applications of registered fungicides can help if multiple applications are made during periods of active growth of the pachysandra (much of the growing season, unfortunately). For a large planting some recommend mowing the plants to 1-2" during dry weather, with a bagger attached to catch the diseased tissue. In a small planting one can remove infected plant parts. Severely diseased plants with basal stem cankers should be dug out and destroyed. Avoid overhead irrigation.

Click on the small image to view a larger image.

Foliar symptoms

Close-up of foliar symptoms
Dieback due to stem canker

Fungus sporulating on stem

Close-up of infected stem

 

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Last updated: 3 June 2003/amd
The Plant & Pest Diagnostic Laboratory at Purdue University