Marigold Flowers

[abigri@iaw.com]

The flowers on some of our african marigolds show a black rot, which starts
on the edges of the petals and rapidly spreads over the whole flower. The
dead parts turn black and somewhat shiny. 

We also see this rot in flower buds that are just cracking open. From the
outside the buds appear healthy, while the entire inside is already black.

The symptoms would resemble simple Botrytis, if not for the black, almost
slimy appearance of the rot.

Would anybody have an idea what we are looking at ? Any help is appreciated.

Albert Grimm
Jeffrey's Greenhouses Ltd.