Question
Hi Jim,

for the second year now, one of our cymbidiums (a white) has developed black/brown spots on the blossoms...have tried to find out what to do, but with no success...can you advise? ...is there a plant medicine we can use to elimiate the spots? ...our other cymbidiums have no trace of the spots...just the one in question...please help if you can...
Much appreciation,

Kevin Irvine

Answer
Hi Kevin,

While I cannot be positive, I believe those black/brown spots could be botrytis which is a fungus.  Botrytis can appear very quickly and if not removed within 24 hours of its appearance, can permanently stain the flowers.  As soon as you see a spot, try wiping it off with a Q-tip or paper towel and alcohol.  Botrytis spores are in the air and when they land in a water drop, it can rapidly grow over night.  It loves wet, cool darkness (night time).  To prevent or minimize its appearance, do any watering and misting in the morning to allow enough time for droplets to evaporate before night fall.  It also helps if there is some light air movement around the orchids.  

Lastly, botrytis favors light colored flowers but especially whites.  

Hope this helped.

Jim Kawasaki
San Jose, Ca.