Phal Bellina Yellow Spots
 

Hello everyone.

I have a Phal Bellina that has many yellow spots. It started this fall and only got worst since.

I've inspected the plant thoroughly for pest and can't find anything. I do have predatory mites (hypoaspis miles) and some springtails, occasional fungus gnat in my Catasetums in the summer.

The plant is mounted on cork with some sphagnum Moss. I've cleaned up the mount a few weeks ago while inspecting it. Removed old Moss and added some fresh moss. Didn't notice anything bad there. Has full of healthy roots. It's also growing new roots and a new leave which is currently showing no spots. The previous leave that grew in fall up to January was fine initially, but now shows some marks which are different then the yellow spots, I'm thinking this might be due to low humidity in our winter conditions.

The only thing this plant suffered is a lack of light which is now resolved. I had to relocate my plants as my previous growing space is now my son's room. It had very low light from November to February while I was setting up the lights. All other plants I have suffered the same low light conditions but did not exhibit any such symptoms except slowed growth.

I've performed Agdia Virus tests for Cymbidium and Odontoglossum viruses which came out negative, but very well know it could be many other viruses.

I've attached 4 pictures showing the evolution of this from this fall up to today.

First picture is from October 31st. You can see minor yellow spots on leaves and the spike. At that time the plant was getting decent light conditions but might of suffered a brief cold breeze here and there.

Second Picture is from January 6th. You can see the spots increased in size. The new leave grew nicely but starts to show a few pits here and there. At that point plant was getting close to no light and also low ambient humidity (roots were well watered but RH between 30-60%).

Third and fourth picture are from yesterday. You can see how bad this got. The newer leave is full of pits. The one before is 75% yellow spots. Oddly, older leaves show way less yellow spots (has some but really minor). The new leave that is currently growing has no spots but is still very small. There is also small brown dots on the yellow spots.

I really don't want to trash the plant, but starting to think this might be the safest thing to do for the rest of my orchid collection.

Any thoughts? Advice? Someone encountered similar spots etc?

Thanks in advance!
Emmanuel

Just to clarify. The poor light conditions got resolved after the latest leave was fully grown. So the leave that is currently growing is getting proper light and RH of 50%+

Also, in case someone wonders, no water on leaves, ever ever since about November (I used to mist daily). The roots get soaked every other day (when the mount has almost fully dried) but no more misting of the leaves.

Do you fertilize? Does it get a calcium and magnesium supplement?

Orchid Environmental Damage

I use RO water with Orchid Pro from Dyna-Gro. Contains all the trace elements it needs. I also occasionally use Dyna-Gro Mag-Pro which is a supplement of Magnesium. The Orchid-Pro contains Calcium.

You asking cause it's a bad or good thing? Thanks :-)

I had this happen to some Phals but did not know what the issue was. This time, when I noticed that the leaves were beginning to get lighter spots, I treated immediately with magnesium and iron as some of my other plants seemed to be suffering from some deficiency. That has taken care of the matter for all the plants. If your temperature is good and you do not have an insect issue, it might be worth trying.

Ok I'll try adding some Magnesium and hope it helps.

Anyone else?

I'm going to agree with PaphLover and Leafmite on this.

Ok thanks that's good news, way easier to treat that then a virus! So how much and how often should I be adding Magnesium. I thought it was used as a "blossom booster". I would normally use just before spike initiation and as buds develop. Then stop until the next flowering season. So my Phal summer bloomers would normall start getting some in the spring. I was actually gonna start adding the Mag-Pro to the Orchid Pro fertilizing regimen.

I use MagiCal every watering.

Nutrient Deficiency
 

From your photos I would suspect a nutrient deficiency also. If you go to the following site, you will see some photos of orchid leaves with deficiencies:

Diagnosing culture problems - Leaf yellowing

Another thing you can try is googling:

nutrient deficiencies phalaenopsis

When the page comes up, click on Images along the top. You'll see many photos which will hopefully help you identify your phal's problem. When you click on the photo you're interested in, it will take you to the page which describes the cause of the symptoms.

Good luck!