Strange "dots" on Phalaenopsis leave - Orchid Board

Anthony · #1 07-24-2009, 04:52 AM

Recently I've spotted these strange "dots" on a new Phal. leave, could it be a virus?

At the moment this one is in quarantaine in the shed outside (facing the east morning sun, growing lots of new roots) as I don't want to take any risc.

Zoi2 · #2 07-24-2009, 09:33 PM

Could they be scale? Have you tried wiping them off with rubbing alcohol?
Joann

Anthony · #3 07-25-2009, 07:17 AM

Hi Joann, it's not scale. It's also impossible to wipe it off, it's on the leaf itself.

I've taken some other pictures, the plant looks quite healthy, the new leaves are good, the old ones are a bit wrinkled. The oldest ones have strange spots on them too altough it could be caused by the sun.

The strange dots on the new leaf are strange, the leaf is also a bit thinner as you can see more light through.

Blueszz · #4 07-25-2009, 09:07 AM

Are these dots raised, or do they look like pits? In case the leafs are pitted with a brown/black center it could be bacterial or a fungus too. Do these dots feel soft/mushy?

Anthony · #5 07-25-2009, 11:09 AM

It is a small pitt with a white/brown dot in the middle.
I've found a small green raised dot on an old leaf too.

Zoi2 · #6 07-25-2009, 08:20 PM

Hi Anthony, I don't know what it is. When you find out, please post it.

Blueszz · #7 07-26-2009, 06:26 AM

Raised dots can be 'blisters'. Hard to say if that's the case without seeing it. Blisters can occur when there is excess of water in colder weather, for instance when the plant gets watered late in the evening when temperatures drop. I saw it happen during my s/h experiment.

About the pitted spot. Recently I had a plant with a black pit and it had the same yellow margins around the pit as I could see in one of your pictures. I still don't know what it was, but after watching it for a week I could see it was getting larger. I cutted a part from the leaf, to prevent spreading, as it was on the newest leaf. I treated the wounds on that leaf with with cinnamon. Problem seems solved now, but I don't know what caused it. You might want to remove the pitted dots to save the plant. Use clean tools and don't use them afterwards on other plants without desinfecting them. Ideally you want to desinfect your tools after eacht cut you make, even when you only have to do surgery on one plant.

Nicole

Anthony · #8 07-26-2009, 07:28 AM

Hi Nicole, I've taken pictures of the raised dot on the old leaf. It does look a bit the same as the pits.

I'll cut off a part of the leaf and treat the wound with cinnamon.

My best guess would be that it's a wound caused by some kind of insect that drills a small hole in the leaf which then infects.

lepetitmartien · #9 11-03-2014, 10:26 PM

Quote:

Originally Posted by Anthony

Hi Nicole, I've taken pictures of the raised dot on the old leaf. It does look a bit the same as the pits.

I'll cut off a part of the leaf and treat the wound with cinnamon.

My best guess would be that it's a wound caused by some kind of insect that drills a small hole in the leaf which then infects.

(I'm writing about the spot with the dry center.)

I've had similar "spots" on one of my Vanilla. It occurs on normal summers only (that is, not in 2014). So either it's a kind of stress issue, or an insect occurring only at that time.

I've marked similar marks (with variations) on vanillas at the Serres d'Auteuil in Paris, and at Chèvreloup (orchid collections of the MNHN). I've asked the gardeners in charge but they are at a loss too.

I've never seen this on my phals, even those close and near similar conditions (save light).

Now, I've marked two different ways it appears on leaves:
- On my Vanilla, the spots are making a line about 15-20 mm from the edge of the leaf.
- On other Vanilla I've seen and a case someone asked me about, the spots though of same figure, were irregularly placed all over the leaf.

It does not evolve on my Vanilla, but I've seen it evolve on the others that makes me think there may be blisters, and a fungus either the cause or invading thru the wound. It then looks like a brown crater.

My 2 cents for now

learning2letgo · #10 07-26-2009, 08:04 AM

Your leaves looks slightly wrinkly to me which makes me wonder if your phal is in too large a pot? I've gathered from my own experience that until a plant establishes a great number of roots that it needs to be confined to a smaller pot.

Also, if you're worried about something wrong with your orchid (virus, etc.), perhaps you could douse the plant with some hydrogen peroxide just as a precaution. I had one phal that the velamen on the roots looked haggard but not rotted - I used a peroxide treatment on the plant and it seemed to perk back up almost overnight. Best of luck in whatever the issue may be with your 'chid.