The Purdue Plant and Pest Diagnostic Laboratory

What's Hot at the P&PDL
November 30, 2011

A New Boxwood Blight in the US

Gail Ruhl, Plant Disease Diagnostician

A new boxwood blight, caused by the soilborne fungus Cylindrocladium pseudonaviculatum (= Cylindrocladium buxicola) has joined the ranks of diseases that ‘plague’ boxwoods. This new disease has beenconfirmed on nursery plants in several states (NC, VA) and on boxwood growing in a residential landscape in CT. The first symptoms of the disease are leaf spots that progress to twig blight and rapid death of the plant (see Figs 1,2,3).

If you suspect that this disease may be affecting your boxwoods, please send samples to us at the Purdue Plant and Pest Diagnostic Laboratory for confirmation.

Note: common diseases found on boxwood in Indiana include Phytophthora root and crown rot and Volutella stem blight.

More information:

What do Pachysandra and Boxwood Have in Common? March 19, 2012 - Most up to date information on boxwood blight

A Boxwood Blight New to the US, Cylindrocladium pseudonaviculatum (pdf file) - NPDN Pest Alert

The 'box blight' pathogen: Cylindrocladium pseudonaviculatum (pdf file) - USDA-APHIS-PPQ-CPHST and NCSU-Department of Plant Pathology

Boxwood Blight - A New Disease for Connecticut and the U.S. (pdf file) - The Connecticut Agricultural Experiment Station

A new pest to the U.S. Ornamental Industry: The 'box blight' pathogen (pdf file) - NC Pest Alert

Click image to enlarge

Fig 1. Symptoms of lower branch dieback caused by Cylindrocladium buxicola on Buxus sp.
Kelly Ivors, NCSU, Dept of Plant Pathology

Fig 2. Leaf spots caused by Cylindrocladium buxicola on Buxus sp., Ct. Dept. of Ag

Fig 3. Stem lesions caused by Cylindrocladium buxicola on Buxus sp.; M. Munster, NCSU, Dept. of Plant Pathology

Fig 4. Fungal sporulation of Cylindrocladium buxicola on the underside of  leaves of Buxus sp.
Landis Lacey and Kelly Ivors, NCSU, Dept of Plant Pathology

Fig 5. Fungal sporulation o fCylindrocladium buxicola  on stems of Buxus sp.
Landis Lacey and Kelly Ivors, NCSU, Dept of Plant Pathology

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