Friday, October 28, 2011

Sample of the Week: Botrytis Blight of Pansy

Botrytis Blight on Pansy (Photo: Mike Munster)
This week we received pansies from raised beds in a trial garden in Henderson County, North Carolina. The roots and crowns were in good condition but some of the flowers, flower stalks and leaves were decaying. The main symptom on leaves was a very watery rot. The fungus Botrytis cinerea was observed sporulating on some of the material when we received the sample. Sporulation was heavy after a day of moist-chamber incubation, as indicated by distinctive masses of gray spores. Making a diagnosis when Botrytis is involved can be tricky, because the fungus can be both a secondary invader and a primary pathogen. It often infects spent blooms and then moves into other parts of the plant. In this case it appears to be fairly aggressive, so Botrytis blight is the diagnosis.

Wet rot of pansy leaves caused by Botrytis (Photo: Mike Munster)
Stereomicroscope view of pansy flower stalk with sporulation from Botrytis cinerea
(Photo: Mike Munster)
For more information on Botrytis Blight, click here
Thanks to Mike Munster for this "Sample of the Week" submission.