Question
I 'm an orchid newbie.I bought a flowering Dendrobium plant 3 weeks ago.But now I think, my plant is in trouble.One of the leaves at the base shriveled,turned pinkish and fell off, a week back.And the second one (at the base)seems to be next.I checked the other two leaves to find that the lowerside of the leaves have turned pinkish.I have been watering carefully every 8 days.The upperside of the leaves are light green.And the plant is kept in a west facing window.A new flower bloomed at the same time the leaf fell off and seems healthy today as well.And there are white patches on the leaf that is drying up now.Please help!I think my plant is dying.What should I do?

Answer
Hello Binti,

It sounds like your dendrobium orchid has two problems, I'll try to take them one at a time.  

First, the leaf color and shriveling.  The leaf color may be due to too much direct sunlight in the west facing window which tends to be very bright and hot.  Try moving it to where it will be in bright light but not direct sun.  Also, it would help if there were some light air movement around it.  Water it when the potting mix becomes barely moist, this may be from every 3 to 7 days during warm weather and every 7 to 10 days in cool weather.  Temperature should be between 60 to 85 F and humidity above 50% (if possible).  

White patches on the leaf could be either mealybugs or boisduval scale.  Both are insects that feed on the leaf, sucking the life out of the leafs.  You can try cleaning them off but that would be an ongoing job as new insect eggs hatch.  Go to your local garden center or nursery and ask for a systemic insecticide that is recommended for orchids, mix it according to directions and water the dendrobium.  It will take a minimum of three applications spaced one week apart to get rid of them.  You should do this treatment in the fall and in the spring to keep those insects under control.  

Hope this helps save your dendrobium.  

Jim Kawasaki
San Jose, Ca.