necrotic spots, leaf discolorations, what is it?

[katsucats]

Okay, so I'm new to the forum and new to growing (orchids, at least).

After I bought the orchids, I looked all over the net finding any relevant information... and became very paranoid. I even bought 25 of those Agdia strip things, and it turned out they were handy. One of the plants that were shipped to me as a "gift" for buying 4 plants turned out positive for ORSV. That was thrown away. The remaining plants were potted in S/H medium and left in my backyard. I had neglected them for awhile, but now I'm going to do it seriously.

I had one plant, nearly a year later after having bought it and tested negative, turned positive for CymMV (that was thrown away). How? I don't know.

Now, I have 3 plants left, and I hope to save them.

I trimmed off most of the mushy roots, and moved these to my bathroom by a west window about a month ago. I've also tested them for viruses multiple times, a month apart. They were all negative. The plants appear back in growth after the move, albeit slowly. But there's a couple things I'd like to ask people more experienced than I, just to be sure...

1. I have these perfectly circular necrotic spots all over my Rhynchovanda Colmarie, which I assume are bacterial brown spots. I hope someone can confirm. I've been spraying Physan 20 and they don't look like they're spreading.

2. Those wrinkled leaves, I'm assuming is cold damage or dehydration from the period I left them outside over the winter (mild winters here in SoCal, but still...). I hope newer leaves return to normal.

3. The plant has a lot of these circular spots (ring spots?). Like I said, it tested negative for CymMV and OSRV, but what are they? They could be fungal or something, or some other virus that I have to spend another $100 on? Aggravating.

4. Here's my Dendrobium goldschmidtianum, which also tested negative for the 2 viruses. It has weird leaf discolorations, that I recently discovered. I hope it's just heat stress or something, and not ByMV or DeMV, or TMV (we did have a smoker in the house, he's now gone).

Thanks for reading this, and I'll appreciate all the help I can get.

P.S. It won't let me post any URL's, even if it's linking to the gallery from the same site... so... please check my gallery for more information.

[camille1585]

Some pics would really help, but I don't know how to get to your gallery, the icon for it is not there (should be a little camera under the post count).
This should help you out to post pics, there are many way of doing it: http://www.orchidboard.com/community...ng-photos.html

[katsucats]

Okay, it looks like the key is to use "Attachments" instead of "Insert Image".

[Bud]

the plants experienced cold...
the black spots on the vanda was cold water drops and the sun combination...then fungi developed
this is the time to bring out the big guns: physan 20 or captan...spray them in two weeks intervals...then bring them outdoors in the shade to recupe...its the warmer months and the humidity in your atmosphere will be a great help to the plants
*you have a catasaecum type of plant in rest(no leaves) no water for this plant until it brings forth at least 5 inches of new growth(be very disciplined about this...no water or the new plant that comes out of it will be weak=the cane has enough nutrients for the plant to produce a new growth)...let this rest in a cool shaded place indoors

[katsucats]

Thanks for the response. I didn't realize cold water could make such a mark... Do you have any ideas on what the uneven (yellow-green) colors on the Dendrobium might be?

About the Catasetum... I got real impatient end of March, wondering why it wasn't growing already, so I watered a bunch of times and that might have caused one of the older spikes to rot. I had to cut the whole thing off. I dipped it in Physan 20, then dumped a bunch of cinnamon all over it. Anyways, I see a new spike out now and it's just starting to form roots, and I've also updated myself on a culture sheet, so I will follow your advice on withholding water until new roots are fully formed. I just hope the roots aren't completely discouraged from growing from those waterings.

[camille1585]

For Catasetums, water is withheld until the growths are somewhat developed, precisely to avoid the problem you had; rot. Any water staying in a new growth is deadly. Don't worry, the new growth will be fine, the old bulb is there to feed it until you start watering.

The uneven coloring on the Den could have been some sort of infection, but the lpant looks quite healthy now. In your first Den pic though the leaf looks a bit dehydrated. Are you watering enough?

[katsucats]

The Dend is yellowing and losing leaves once in a while. It will lose 2-3 and then it will be fine for 1-2 months. It could be something I did in between.

I will water it more often.

[katsucats]

This thing was dropping leaves, which I read was "normal" to some extent. One of the canes only has top leaves left, and the new cane doesn't seem like it's growing. I'm afraid it might have aborted (there used to be 2 others that have browned out). I transplanted it into a smaller clay pot because I read that Dendrobiums like to be root bound. I also watered more, which doesn't seem like it's helping. Today, I moved it outdoors on the south side in the shade.

Please see pictures. First one is of the root and the new cane that isn't growing. I'm practically braindead when it comes to spotting "root rot", because it looks like every root strand has sections of brown, and sections of white. So I'm not sure what's going on here. There are tiny bumps on the new cane, but that isn't going anywhere.

The last 2 pictures show what looks like a fungal or bacterial infection. Notice the random yellow circular spots on the front side of the leaf, and scarring on the back side. I have no idea what to do, Physan 20 doesn't help. And as mentioned before, this plant tested neg for cymmv and orsv.

Someone please help.

(On the other hand, my Cycnodes seems to be growing quickly, but I'll be holding out on the water until the roots are longer...)

[camille1585]

Color doesn't matter for the roots. If they're firm, they're good. Anything hollow or mushy is dead.

Have the spots continued spreading about spraying with Physan? Damage is permanent on plants, spots and discoloration don't go away. Success is judged by the symptoms no longer spreading.

[katsucats]

Yes, it looks like it still might be spreading. If there are sections of a root that are mushy, and sections that are firm, should I get rid of the whole thing?