Are all black areas on orchid leaves bad?

[carykeshen]

I just picked up a "bag" baby at Home Depot, Dendrobium spectabile.

It seems like a very robust plant with 5 or 6 canes, but has a few areas on some leaves that are black. Small areas, not wet or mushy, firm but black.

I sprayed it with hydrogen peroxide 3% after I repotted it just in case but I wondered if I was being overly cautious so I thought I would ask the above question.

[Ray]

Most healthy plant parts are not black, but that doesn't mean that black spots are to be worried about - some yes, some no. A photo would really help.

[carykeshen]

Hello Ray - Yes, I was anticipating your request for a photo. It is not very clear, but I hope it helps. Also, the black is not on any of the new growth, and I removed, what appeared to be the oldest (and smallest) leaf which had black on it.

[SouthPark]

Originally Posted by carykeshen

Also, the black is not on any of the new growth, and I removed, what appeared to be the oldest (and smallest) leaf which had black on it.

Does this mean that ----- in the photo you showed, you removed that particular leaf with the black on it?

Also - is/was the black patches on 1 side of the leaf? Or both sides of the leaf?

[carykeshen]

Originally Posted by SouthPark

Does this mean that ----- in the photo you showed, you removed that particular leaf with the black on it?

Also - is/was the black patches on 1 side of the leaf? Or both sides of the leaf?

No, the leaf that I removed, is not the leaf in the photo. On the leaf in the photo, the black only appears to be on the underside of that leaf. On another leaf the black section is only on the very tip of the leaf (on both sides). Most of the leaves have no black on them.

[SouthPark]

Thanks for explaining Cary. The hydrogen peroxide treatment sounds like a good idea to start with.

If you use a methylated spirits dampened cloth to wipe the leaf ..... will some of the black material transfer over to the cloth?

[AnonYMouse]

Methylated spirit=denatured alcohol to "murkans"

Are the black spots dry? Is the surrounding area soft, wet or bruised looking? How much of the plant is affected?

At minimum, I would isolate the plant. I would wipe down the leaves and pbulbs with rubbing alcohol (Isopropyl alcohol). I might even remove that leaf.

[carykeshen]

Black spots are dry, not soft, not mushy.

[Ray]

Hard to say what caused them, but if they are not spreading, don't be overly concerned.