infection

[Stone]

I have a fungal infection developing on 2 or 3 paphs. It always attacks the lower leaf where the leaves meet. It starts as a yellow discolouration and gradually turns brown. It distorts the leaf around the area of infection. Spraying with Chorothalonil seems to stop it (slowly). It seems to like warm humid conditions. What the hell is it?

 

[wjs2nd]

Any pictures? Could it be rot?

 

[Stone]

Pictures..







This the same thing about 12 months old


About 3 months old

 

[Justin]

I used to get very similar rot, with the orange soft spots that would start in the new leaves.

For me, the answer was to increase Ca and Mg in feeding. For immediate treatment, Phyton 27 is effective at stopping the rot from spreading throughout the plant.

 

[wjs2nd]

Hmmmm, I'm not sure. Sorry I can't be more help.

How is your air circulation? Maybe a little more air movement would help. Try anything like H2O (hydrogen peroxide)?

 

[Stone]

Justin. The spots are not soft, just yellow colour on the leaf. They get plenty of Ca/Mg.
Billy. Air has been good lately with the evap cooler on all day and a fan all night. But yes I think even more would be good, but the bills!!!!!!

 

[gonewild]

Can you take closeup photo of the fresh damage?

It somewhat looks like it could be damage from tiny micro slugs or snails. The first picture looks a little like the trail left as the slug eats in a wandering pattern. But that is a guess from looking at the small image with not such good eyesight.

 

[consettbay2003]

I had similar damage and after checking the areas out with a magnifying loop discovered I had thrips. I think the thrips caused damage to the leaves that allowed a secondary fungus infection to set in. A systemic fungicide/pesticide cleared up the problem.

 

[limuhead]

I have seen this on some of my friends intergeneric oncidiums. According to him, and he is a commercial grower with thousands of oncidinae and paphs, it happens sometimes when the fert level is too high and it is too damp and or not enough light. It made me sick to my stomach, but we ended up throwing away thousands of intergenerics and a bunch of paphs as well. I would isolate the plants that affected if possible...

 

[abax]

Can you buy Cleary's 3336 systemic fungicide in Australia? What about
Orthene 97% granular systemic insecticide? I found that one or the other
takes care of just about any plant problems. I think OFE International
carries both.

 

[Secundino]

As the first markings outline the leaf growing in the older leaf - a sort of open 'v' - I would say samething sits in the crown with the water und hurts the leaf tissue when it dryes up; that would explain the color and that it is no soft rot.
Perhaps it's not necessary to increase the ventilation but to rise the affected plant about the level of the others - just by a topdown pot beneath. I too believe it's a secundary infection.
Could it be that while potting the affected plants, some dirt got into the crown? It resembles the same color than the lava - some kind of caustic dust (high iron-minerals?)? I always wash the lava a lot to get rid of this dust.
Just thinking aloud...
Luck!

 

[wjs2nd]

Another thing, thinking out loud, I have found brown listerine very effective for killing/curing many things. Plus, it does hurt humans or poison the area.

 

[dodidoki]

Are you sure that it is infection? There are few of my plants with orange spots- similar to your first picture-, I got these plants "with these spots", but these spots do nothing at all. Dry spots and no spreading at all....

 

[labskaus]

This looks pretty similar to what I attribute to false spider mites in my collection.
Look here for more info:
http://www.hark-orchideen.de/Pflanzenschutz/Weichhautmilben/bilder.php?lang=en&navID=99

 

[Stone]

Are you sure that it is infection?

Yes positive

 

[Stone]

This looks pretty similar to what I attribute to false spider mites in my collection.

This definately a primary fungal infection. I have been spraying regularly for mites and mealybug. I have looked very closely for any pests and I cannot see any. Apart from one plant last year, the problem has affected about 4 plants now all in the space of about 2 weeks during very hot and humid weather/conditions. Maybe I helped to spread the spores by dipping the plants in the same bucket of water? As I said, I believe I can stop it with chlorothalonil and I also used micro-fine wettable sulphur on all the plants yesterday just to make sure but I would love to know the correct identity of this disease so I can research it. You must know your enemies well! The internet doesn't help very much.
This looks like the same thing to me but no one there seems to know what it is either. It always seems to start under the leaf not on top. And it starts off yellow and then turns like this:
http://www.rv-orchidworks.com/orchidtalk/general-orchid-culture/698-paph-leaf-problem.html
Here it is again (second pic) Again no real answers HAHAHA!
http://www.rv-orchidworks.com/orchidtalk/orchid-ailments-compost-pile/20159-brown-spots-paph.html

 

[cnycharles]

thrips are very resistant to many chemicals, if they are the problem. if you do have them, I would use the sugar-based novel insecticide that Ray B sells as it eats through them instead of being a poison

This definately a primary fungal infection. ... Maybe I helped to spread the spores by dipping the plants in the same bucket of water? As I said, I believe I can stop it with chlorothalonil and I also used micro-fine wettable sulphur on all the plants yesterday just to make sure but I would love to know the correct identity of this disease so I can research it. You must know your enemies well! The internet doesn't help very much.

edit - I didn't read this post before I first replied. if it has been really hot and humid, and there was a disease on something then it is very possible to spread something by dipping them all. if the weather is drier and things can dry out more quickly it might not be as much of a problem but when things may not dry out quickly, disease could spread easily by dipping in the same water

 

[Secundino]

Maybe I helped to spread the spores by dipping the plants in the same bucket of water?

Indeed. And not only if it is fungal infection. Whatsoever is the origin, you will spread it with this method. But I believe you knew this? If not: isolate the affected plants from the rest; look closely on the neighboring plants for any infection. Never work first with the affected plants and then with the healthy, try to find a 'quarantaine routine'.
I'm still not convinced that it is a fungal infection primary.
Wish you luck.

 

[e-spice]

I would try dusting with cinnamon. Very inexpensive, nontoxic, and surprisingly effective.

 

[Stone]

.

Never work first with the affected plants and then with the healthy, try to find a 'quarantaine routine'.

Good idea!