What is wrong with my Dendrobium( white thing on the leaves). Please help me...

[danliz]

Hi everyone,
I am new to orchid so all of the orchids that I have are having problem, and I don't know how to solve it. I tried to research but still don't get it.

I bought this Dendrobium one more month is a year now. At first, I put it them in the house because it was blooming so pretty. After blooming and grew one new stem (which have one leave cut) at the same time, I put it outside and decided to re-pot it. I didn't know what kind of pot or mix so I put it in a huge pot with a lot of charcoal and covered on top with moss. The leaves of new stem grew longer than normal, and the stem never grew new leaf. At the same time, some white thing appeared (as you can see in the photo) on both side of the leaves. The leaves are dull/rough/drooping), and another new stem grew. But the orchid seem not healthy, so I decided to re-pot it. The root system was rotten, and very little new roots grew. I cut off one of the old stem that you can see in the picture (the one has only two leaves) because its root was all rotten. It actually had no root at all, but I gave it a try by still potting it in another pot (again the pot was huge too). I placed the another half which had two new stems and one old stem in its huge old pot. After a while, white thing was everywhere on both Den. orchids, and they showed no grow so I re-potted them again. This time they are still with alot of charcoal on the bottom and moss on top, but they are placed in a smaller pots (as you can see on the pictures). The stem that had no root showed two new tinny roots, and the other showed a few new roots. But I think I am gonna repot them again using at a lot tree fern and moss and bit of charcoal. What do you think?

So that is the history of this Dendrobium (now become two Dendrobium),

So my questions are:

Why the leaves grew longer than normal?

why are they so low at growing?

What are the white thing on both side of the leaves and the tree (sun burned? or bug?)?

There are some slightly yellow spots and tiny black spots on the leaves as well. Why?

Should I quarantine them with my other Phal. orchids?

What should I do now?


Thank you so much in advance for your help!!

[danliz]

I just found out after a long research that my Den. are suffering from thrips which caused silver streaking on the leaf. Have anyone successfully treated this problem?

In the mean while, I am gonna try insecticidal soap by mixing liquid soap and water and spread on them. Have anyone tried this method before? Please tell me how to use this method.

I hope the thrips haven't spread to my other orchids. Im so nervous and worry now

[Bill U.]

I am not familiar with the symptoms of thrips, but I would definitely encourage you to look under the "Pests and Diseases" Forum here on OB for more detailed information with them.

As for some of your other questions:
- the white part on the main stem of your plant is called a "sarong". This is a protective layer/sheath that many orchids put out as a means of protecting new, maturing growths. Most often seen in cattleyas and dendrobiums, to the best of my knowledge.
-Leaves can be growing longer if they are experiencing less light than their other sets of leaves. They are stretching out the leaf in the effort to create a larger photosynthetic space to try and receive more light to provide the adequate energy to the rest of the plant.
-I can't tell that that thing on the top of your plant is from the photo.
-Sometimes spots like those can appear as a result of disease, fungus, insect activity, or sunburning/severe changes is culture. If you have repotted it and then put it in a new place recently, I would say that it may be a result of those changes and your possible insect activity.

I would quarantine this plant because if it is thrips, they WILL spread if allowed. Again, the "Pests and Diseases" forum will have lots more help to give you.

---------- Post added at 02:52 AM ---------- Previous post was at 02:50 AM ----------

*Also as a side note, I have not grown dendrobiums before, but the canes and leaves in your pictures look extremely wrinkled- indicating that the plant is not getting enough water. I would make sure that you are giving it appropriate amounts of water, as a drought-stressed plant makes for very susceptible victim to insects and all sorts of other nasty things...

[danliz]

Thank you for your reply. I will do as you wrote. The thing on top of the plant was a old death flower spike.

[Brenda Aarts]

Thrips can be very persistent. You may have to spray with something stronger than insecticidal soap, speaking from experience. When you think you are rid of the thrips.... spray a couple of more times a week apart to make sure. As mentioned by Bill I would encourage you to research this further in the pest/disease section of this forum. Good luck.