Virus, another disease, or??

[JeanLux]

This is not an easy thread for me to publish, but I finally decided to show my orchid leaves' problem here and to read your opinions. I suppose that nobody really likes to show the downside of his orchid collection!

I took the opinion of a luxembourgish specialist (?) who told me that those rings/spots on the leaves I showed him were no disease but maybe caused by dropping of fertilizer-containing water on them. the roof of my lean-to greenhouse is very flat, so concentration of water and dripping is rather usual (unfortunately).

Quite some of my plants of different genera show these symptoms:

Paph hybrid:


underside:


Laelia anceps leaf:


Phrag leaf:


Another Laelia leaf:


Cattleya:


Rhyncholaeliaa digbyana.



Now, what do you think of this? Leaf tissue problem, virus (Cymb.?) or other disease? How to cure or discard?

Thanks for any help
Jean

 

[Shiva]

I too have those ugly markings on some of my leaves. My guess is most times, it's some kind of fungus. Cold water dropping from the roof may kill the leaf tissue and subsequently offer a good entry point for a fungus. You can move the plant to some other spot but the original markings will not go away or, in my expoerience, expand. I'm less certain it's the cause of the banding on your Laelia anceps. I'm suspicious of the alternate yellow bands. If it was me, I would trim the affected leaves or cut them off, and I would isolate the anceps from the others. If it's a good clone, have it tested for virus.

 

[monocotman]

virus?

I agree with Shiva - the only one I'd be concerned about is the anceps with the yellow rings. The rest could easily be caused by drips or mechanical damage to the leaf and subsequent fungal infections,

David

 

[Hera]

Thanks for showing these, its an interesting thread.

 

[Rick]

Do you ever get any scale or mealies?

Between the Lalia and the phrag, I only saw 2 with "bullseye" type markings that look reminiscent of some of the virus photos I've seen.

I also have things that look like this. Particularly the "Cattleya" leaf picture.

 

[JeanLux]

Do you ever get any scale or mealies?
....

tons of mealies unfortunately!!!! An everlasting fight !!! Jean

 

[Rick]

tons of mealies unfortunately!!!! An everlasting fight !!! Jean

In my GH I'd almost always find a pile of mealies directly under the place on the leaf where you see the type of surface damage in several of your pics.

I've hear conflicting reports that mealies do or do not promote virus infections.

Mealies and scale penetrate the leafs and suck nutrients out the plant causing local damage at least. This local damage makes in-roads for bacterial and fungal infections. The comparison in my thinking is that you are seeing scabs and rashes associated with some type of mechanical or pest damage.

If growing conditions are good, then like scabbed over bug bites, the plants natural immunity systems will keep the damage from taking over the whole plant, and hopefully just stop with a small local scar.

I'm not good at identifying virus on top of that.

 

[Erythrone]

I learned with my plants (many had CymMV and/or Odontoglossum ringspot virus) that some symptoms of virus can be seen when the leaves are rather young. We can see yellowish spots or lines. When the leaves are older, necrotic zones can appear on the "yellowish zones". Of course, some fungi can do this. But I think virus almost always do that.

So if the spots appear on mature leaf, I think that it is not virus.

I also found that most of my plants with virus were symptomless. I tested many of them last year and many of all positive ones for the 2 viruses were discared.

I am concerned about your Laelia anceps too..

 

[SlipperFan]

I agree about the Laelia anceps and would have it tested.

 

[Eric Muehlbauer]

At least as far as the paph is concerned, its not a virus. Almost all my larger paphs have at least one leaf with an area like this. Many reasons..scale and mealies....yes...a mechnical injury, yes...limited bacterial or fungal infection...yes. Any of those could be explanations. Fortunately virus is not. But I agree with everyone else's concern about the Laelia.

 

[NYEric]

The paph was grown too dry at some point. Soot spot on the phrag, clean me!

 

[tenman]

The paph looks more like physical damage.

L.anceps looks virused, but testing required for proof.

Phrag looks more like cersospora bacterial infection.

Second laelia leaf - scary, test for virus.

cattleya could be anything, maybe just cultural damage.

Digbyana, hard to say. If the leaf was damaged first, then likely bacterial/fungal. If the 'damage' occured as a result of the condition, test for virus.

In all above cases where virus test is negative, treat for fungal/bacterial disease, beginning with removal of all affected tissues and isolation. Watch closely, repeat treatments and keep slicing off anything diseased. It can take a year to clear up some diseases completely. treating other plants is recommended as well, as these things can spread easily and other infected plants may be asymptomatic for months.

 

[JeanLux]

Thanks a lot!!!! Now must try to find a place here in Luxembourg (or in Germany maybe) to have those virus tests done !!! Jean

 

[tenman]

Thanks a lot!!!! Now must try to find a place here in Luxembourg (or in Germany maybe) to have those virus tests done !!! Jean

You may find ordering test kits online easier and less expensive. I use Agdia test kits. I don't know if there's a minimum order size but you can always get some friends to share a larger order if necessary.

 

[Erythrone]

I use Agdia too.

There is also Pocket diagnostic in Europe:

http://www.pocketdiagnostic.com/products/21

You should be aware that those tests don't allow to detect a lot of virus (only Cymbidium Mosaic Virus and Odontoglossum Ringspot virus)

 

[JeanLux]

Oh fine, thank you 2!!!! Jean

 

[Brian Monk]

What do the healthy leaves look like? Are these leaves from older growths or from new growths as well? How long before the new growth is affeced by symptoms? It is difficult to determine the cause of disease without knowing the context of the problem, and individual plant history is important. Paphs, Phrags, and Cyps are extremely resistant to viral infection, a fact that is known and exploited in commercial greenhouses. Cattleyas are particularly more susceptible, but again Paphs/Phrags are especially resistant to those viruses that infect Catts. Could we get some whole plant shots?

 

[biothanasis]

The first one looks like mechanical damage...! The black spots that look like bites are treated with pure spirit we use at home one a batonet or a copper based antifungal/andibacterial paste. Most likely, these leaves will be dropped of the plant sooner or later, especially if these markings grow in shape. I have no idea if the whole plant is affected though...!

Good luck!!