Question
Hi, Jim. I've enjoyed scanning through all your answers to others' quandaries.
I share your view that orchids are rewarding and confounding. I have one
that's really confounding me.

I live in Los Angeles, Hollywood Hills, and have a pseudo-orchid house,
covered in shade screen, polycarbonate on two walls, slatted benches, open
air. It's very sunny, and I have to keep extra shade screen over many of the
plants in very hot weather. A lot of them have sun spots.

Anyway, over the past two weeks a 6-year-old cym suddenly started to
wither. One bulb at a time, the leaves went yellow, then brown, and yesterday
I investigated and was saddened to realize that the plant was soaked through.  
Most of the bulbs were rotted and soft, and the medium was full of white
fungus.  Only one leafy bulb and a few back bulbs are still firm/hard.  so,
here's my question: I've cut out the good part and have it sitting out to dry,
but I'm wondering if it's too risky to put the plant back into the orchid house
with the rest of them.  As painful as it is to lose a cym (I think I've only lost
one once before), should I can her?

Answer
Hi DM,

Golly, gee whiz!  You mean people read my comments?  (grin)  

From your description of what you found when you unpotted the sick cym, it sort of sounds like the white fungus you found is what is called snow mold (Ptychogaster species).  This fungus is water repellent and once established slowly covers the roots and thus they do not get any water.  

What you have done so far is okay but if you try to repot the healthy looking parts, the fungus will probably grow again unless the entire cym is treated with Terraclor or Turfcide.  I am not sure where you can get either of these but you might try checking with some garden centers or chemical distributors that serve commercial nurseries and farmers.  

Once treated, it should be okay to put it back in your growing area.  A word of caution regarding your other orchids, this fungus may be present and growing in some other pots so be on the lookout for any signs of trouble.  

You can help reduce or minimize the burning of leaves during really hot weather by misting the leaves.  I don't mean spray them but rather mist them.  There are misting kits available at some garden centers, they really don't use a lot of water because the water mist is so fine.  There also is a hose end attachment called the Fog-it (about $15.00), look for one that is rated at 0.5 gallon per minute.  This last one is what I use.  What you want to accomplish is to cool down the leaf temperature.  Touch the leafs and if they feel warm, that means they are close to being sunburned.  After misting they should feel cool to the touch.  During your Santa Ana's, you may have to mist several times a day.  

Living the the L.A. area, have you attended the orchid show and sale in Costa Mesa, Orange County?  There is another show and sale at the Huntington Gardens in the near future also.  Although I've never been to either, I've heard lots of good things about both.  Then of course there is the one in Santa Barbara in March, I've gone to this one for over 20 years.  

Hope this helps save it.  Good luck!

Jim Kawasaki
San Jose, Ca.