Black rot or normal aging/yellowing?

[j0ker918]

I just got a new catesetum last week and it came entering the dormancy phase. The leaves are all starting to yellow and one has fallen off on it's own. The underside of the leaves also have these diffuse tiny black spots which get larger as the leaves yellow. They look like aging banana skin and are all on the underside but as the leaves yellow completely, they start penetrating towards the front. Is that normal? I don't know what black rot vs normal dormancy on a catesetum would look like since this is my first one. So far the bulbs look completely free of any black. I am hoping the leaves will just fall off soon. I will try to upload photos.

[rcb]

Without seeing pictures, it is hard to say for sure.

But Ctsm leaves, as they drop can get really ugly. Also, rot tends to be wet, not dry, and honestly I've never seen rot on thin leaves like Catasetums.

If it really bothers you, and the leaves are mostly yellow anyways, just cut them off.

[j0ker918]

Here are some pics

[switchblade]

check roots. The black spots on the leaves look like fungi doesnt it?

[j0ker918]

if it is fungus, whats a good fungicide people recommend?

[jpyerry]

Originally Posted by j0ker918

if it is fungus, whats a good fungicide people recommend?

I like Physan 20, unfortunately nobody in the greater Capital District area carries it, most of the hydroponics shops are willing to order it. But, you can get it cheaper and quicker online.

Justin

[j0ker918]

Ok so now I'm worried because I went home and tried to scrape off some of the black with my fingernail and some of it DID come off making me even more concerned that it IS fungus and not normal aging. I ordered Physan 20 online, but it'll take at least a week to get to me. In the meantime, I looked for some homemade antifungal recipes. Here are a few I found.

1) Cinnamon + 70% Rubbing alcohol (+/- soap)
2) Hydrogen peroxide
3) Very Dilute bleach

I'm thinking of using the cinnamon/alcohol mixture. Does anyone have any experience with these? This is my favorite plant and I will be devastated if the bulbs or blooms get affected. So far the spots are confined just to the leaves. The bulbs are fine and the stalks are taking off like crazy, about 1/2-1 cm a day. Any idea if any of these mixtures will HURT my catesetum, especially if they get on the bulbs or exposed roots? If anyone has made their own concoction, how often do you apply it?

I know it's bad, but I worry about this plant more than some of my patients

[Brooke]

Cut the leaves off - it is going dormant. You don't need to treat it with anything, this is how the typically look when they have served their purpose.

Orchid leaves in general look terrible as they die.

Brooke

[j0ker918]

So I cut off the leaves that are fully yellow. There are still two leaves that are almost all green. Just in case, I wiped those down with an alcohol pad and most of that black stuff came off onto the pad. Then I sprinkled cinnamon onto another alcohol pad and gave the leaves another rub down this time with the cinnamon. Hopefully this helps the plant instead of hurts it. At least it smells nice.