Question
Hello!  I am a new orchid owner/lover.  I received a Phalaenopsis for Mother's Day and it is doing very well.  So, five days ago, I purchased a blooming oncidium.  After I brought it home, I noticed some brown spots on the leaves.  Most are the size of a fat pencil point.  If you hold the leaves up to the light, the leaf flesh is translucent.  Is this a fungus or sun spots?  In general, the plant seems healthy.  There is some new leaf growth around the pseudobulbs and an unopened flower stalk.  Some of the pseudobulbs do look a little shriveled.  Please let me know what you think.  I have isolated the Oncidium until diagnosed.  Should I treat the Phalaenopsis if it is a fungus?  Thanks for you help!  I can send a picture if that would assist you.


Answer
Hi Sandy,

Welcome to the wonderful hobby of orchid growing!  I have to warn you that it can become an all consuming hobby, taking over every available space in your home.  (grin)  

Many oncidiums tend to have tiny black or brown spots on their leaves, primarily towards the tip.  While unsightly, they normally are not harmful to the oncidium so long as they stay towards the upper half of the leaf.  

What causes these spots?  While I'm not 100% certain, I believe it is a combination of factors such as heat, humidity and inadequate air movement.  

So, for now I would say not to worry, but keep your eye on the oncidium to see if their numbers increase greatly.  

Hope this has helped.  Good luck and good growing.

Jim Kawasaki
San Jose, Ca.