miltonia and oncidium with black spots and browning leaves - Orchid Board

MissFlora · #1 (**permalink**) 05-21-2008, 11:04 AM

I have problem identifying the problems for both plants.

Miltonia has browning leaf edges. It is now potted beside shaded (with thin curtains) east window.

Oncidium has black spots and one of the youngest pseu's leaves actually turned yellow. This happened within 2-3days. It also potted beside shaded east window right now.

I water my orchids about every 1.5 week. I sprayed diluted physan 20 on their leaves and some into their medium.

Can someone please tell me what's the disease/pest and if I am doing the right thing now?

Flora.

kiki-do · #2 (**permalink**) 05-21-2008, 11:16 AM

This is just a guess. The Milt is getting too much fertilizer. I think they are sensitive to that. A couple leaves of mine did that and I backed off on fert. to once a month. Seemed to help.
Oncidiums do not like to be sprayed...misted. Are you misting them? That would turn the leaves spotty, such as the last picture shows.
Yellowing, hmmmm, is possibly a sign of aging. Could be other things, but is that one of the older pbulbs?
There are others who will know more than I.
At the very least....this keeps the post on top.

kiki-do · #3 (**permalink**) 05-21-2008, 11:17 AM

Just noticed you said it was a younger pbulb...sorry!

MissFlora · #4 (**permalink**) 05-21-2008, 11:27 AM

Thanks Kiki! Oh...I bought the miltonia about 3 weeks ago and the leaves were healthy. I didn't feed it with any fertilizer since it is blooming. I am not sure why the leaves turned brown all of a sudden. The humidity of my room is around 60F. Maybe I should drain it in water a few times to wash off any fertilizer...

As for the oncidium, I have it for about 2 months now and it was doing great. Just recently, it started having the spots and I think it is spreading to other healthy pbulbs. It really worries me.

I tend to water their mediums instead of spraying/misting. I only sprayed the Physan 20 on them as I am not sure if it is what I am supposed to be using.

This is really worrying me. I hope it is not a bad infestation!

Flora.

kiki-do · #5 (**permalink**) 05-21-2008, 11:48 AM

I tried looking it up in one of my books. The yellowing can be from too much light (which you say is not the problem), early stages of overwatering....if I likes to dry out between watering (I don't think it's that either), and nitrogen deficiency (????). If the pbulb is mushy that is a sign of root rot....but you didn't mention that.
I think the physan was a good move. I would also yard it out of the medium and have a look at what lies beneath. Oncidiums do have a tendency to have spots like in the last picture, but where yours has two things going on...I too would be suspicious. I would be concerned with bacterial or viral disease. Perhaps a good spray of Physan on the roots and new medium.
I'm certainly hoping someone who is familiar with this sees this post. Good luck.

MissFlora · #6 (**permalink**) 05-21-2008, 11:56 AM

Thanks again Kiki! For the oncidium, nope, the pbulb is not mushy...I went on to pull out the yellowed part and realized it is the leaf, not the pbulb. So I think the only thing I can do for it is the Physan.

As for the miltonia, anyone have more suggestion as to why are the tips browned and looked like it is burnt? It has never been exposed to direct sunlight ever since I bought it.

Flora.

Lemur · #7 (**permalink**) 05-29-2008, 12:42 PM

My oncidium has very similar spots on its leaves. I read above they do not like misting, so i have stopped that. If I have any results I will post back later.

Ross · #8 (**permalink**) 05-29-2008, 01:04 PM

As I recall, the spotting is common on Oncidium and really doesn't mean there's a problem. I have many that seem to do this as a normal thing and I don't mist them at all. Wouldn't worry on that one.

As for the Miltonia leaf tips browning, could be a number of things. I tend not to woory about any of my plants (no Miltonias for me) that do this and just trim the ends of the leaves with a sterile clipper. I like to keep nice green plants. If the die-back progresses then I try to find the cause. Even with newer growths, you might get this on outer leaves. I only start worrying when the center leaves do this. Kiki correctly listed several culprits, any one of which could do this. It's now your job to rule out the ones that don't fit your water/fertilizer regime. Good luck.

Soonix · #9 (**permalink**) 05-29-2008, 04:17 PM

My miltonia is doing the exact same thing, it is also in bloom again. My Milt now lost a leaf and the other one is completly yellow but there is new growth coming out between the 2 leaves that turned brown. Otherwise the plant has a lot of new growth and flowers and growing buds so im not too worried.

Chumy