Kerria

Plant Health Clinic Disease Note Issue 23

Sherrie Smith and Jason Pavel

Kerria Blight-Blumeriella kerriae. Photo by Sherrie Smith, University of Arkansas System Division of Agriculture

Japanese Kerria is a valuable but underutilized shrub. It has bright green foliage and lovely yellow flowers over a long bloom period. It is one of the few shrubs that thrive and bloom in both shade and sun. The most common disease we see on Kerria is leaf and stem blight caused by the fungus Blumeriella kerriae.

What are the symptoms of Kerria Blight?

Symptoms are numerous small red-brown spots with purple borders on foliage. Spots may coalesce and cause the leaves to turn yellow to brown and then drop from the plant. Stem lesions are purple-brown, elliptical cankers, which can girdle the stems causing dieback.

What are control options for Kerria Blight?

Control consists of ruthless sanitation along with the avoidance of overhead irrigation and the use of fungicides. You may use Bio Advanced Disease Control in rotation with a fungicide containing chlorothalonil.

Take Aways:
• Clean up diseased leaves and stems.
• Avoid overhead irrigation.
• Begin fungicides at the first sign of disease.

Kerria Blight-Blumeriella kerriae. Photo by Sherrie Smith, University of Arkansas System Division of Agriculture

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This work is supported by the Crop Protection and Pest Management Program [grant no. 2017-70006- 27279/project accession no. 1013890] from the USDA National Institute of Food and Agriculture.