Dendrobiums in BIG trouble!!!

[OnicheK]

Hello,

I noticed some spots on the leaves of some dendrobiums I have - they look as if some black liquid were spread on the back of the leaves. The spots don't seem oily and, at first, I didn't take them too seriously either.

But it is! To the one which suffered the toughest attack (a nobile-type hybrid), it begins to spread towards the pseudobulbs, as you can see in the images below.

I think it could be some fungus, but I have no idea what type and/or how to get rid of it. Other 9 or 10 dendrobiums have it (and one hybrid cattleya), but it only begins now: the leaves begin getting "dirty", but not the PBs for now. It's strange, because the affected leaves are not falling. They stay attached and with this type of spots that cover them more and more.

The infected plants got isolated, but I am not sure that I was in time to avoid further propagation.

What do you think it could be? And how could I treat those poor plants? Are they treatable or should I throw away all the plants that have it?

Should I spray all my plants with some fungicide? What type?

Thank you in advance,

Oana.

[Brutal_Dreamer]

Hi Oana,

I would spray with a fungicide right away. Any fungicide will do the trick. The spots will not be reversed, but should not continue to spread. Also, please make sure you have a fan circulating the air around your orchids. Good luck to you.

Cheers,
BD

[OnicheK]

Hello, BD and thank you for your answer.

I keep all my orchids inside the house, due to the climate here. But those ones were right under the air-conditioner - do you think this may be the cause?

How could one distinguish between the spots caused by fungus and the ones produced by bacteria or something else?

Anyways, I sprayed them all and I will do again in a few days (someone recommended spraying them for 3 times, with a 5 day interval). But how will I know if they're cured or not? Some of them already have new healthy sprouts, while the "mother" has these awful spots. But once replanted, won't they get sick as well? Does fungus live outside of the plant or both inside and outside?

Thank you very much,

O.

[Brutal_Dreamer]

Generally,fungus spots will not be stinky where as bacteria will have a bad odor and be squishy/ nasty. Orchids would not like to be in the path of your air conditioner. I don't know if that is what caused your problem, but I would not recommend keeping them in a direct line with conditioned air.

I *believe* fungus and bacteria can live on the outside as well as the inside of the plant.

Cheers,
BD

[OnicheK]

Hello again,

This is to say thank you - well, my sick den went in bloom!!!

[Brutal_Dreamer]

Wow, good for you. The blooms are pretty!

Cheers,
BD

[cherublace]

precious blooms! they are so cute!

[Cjcorner]

Very pretty blooms....good luck with your plant. That one is too pretty to lose.
Connie

[JoeW]

Terrific!! well done.

[OnicheK]

Thank you, guys! These plants never cease to amaze me