Possible fungal infection on Oncidiums and Cochleanthes/Pescatorea

[KristenReuel]

Hi,

I'd like some advice with what to do about my 2 Oncidiums and 1 cochleanthes/pescatorea. The big oncidium always had dots at the ends of the leaves. I've read that this is sort of normal for this type of orchid. Whatever it is hasn't seemed to bother the orchid, or progressed much. It just bloomed again and has new growths.

However, I wasn't clever enough to keep it separated from my cochleanthes/pescatorea, which has even softer leaves, and it looks like it spread to this plant. It seems to be affecting this plant more than the first one. The black dots are slightly indented into the leaves. All of the older leaves are affected, and a few of the newer ones. The dots are concentrated around the ends of the leaves. My oncidium twinkle's leaf tips have started to get the dots too.

I'm assuming it is a fungal infection, but I would really appreciate your expert advice. Is there a certain type of fungicide you'd recommend that I purchase? If it isn't fungal, what should I do?

So far, I've chopped off the most affected leaf tips with sterilized shears and applied a tiny bit of cinnamon to the wounds. I also tried applying some hydrogen peroxide to the leaves of the plants.

Oncidium



Cochleanthes/Pescatoria

[RosieC]

Oncidium types can be prone to spotting. I'm not sure if this is normal or not on yours.

The spots on your other one would give me more concern. Hopefully someone else will chime in more experienced than me.

[King_of_orchid_growing:)]

At the moment the spotting on your Pescatorea/Cochleanthes is not cause for great concern.

Increase air circulation just a little. With orchids in the Chondrorhyncha/Huntleya group, you want to be very careful not to let the humidity drop too low.

[tucker85]

Oncidiums are very susceptible leaf spotting fungus because they're leaves are thin. Even though that type of fungus won't usually kill an orchid, it is unsightly and it can also spread. You may want to use a fungicide regularly for a while to try to eradicate it. Good air movement and watering in the morning so the foliage can dry during the day are good culture practices that will help. Using a fertilizer that contains calcium or a calcium supplement will help also. You may also have some cell collapse that's usually caused by cold water on the leaves. Let your water warm up to room temperature before putting it on the plants or, at least try not to get cold water on the leaves. Here's a link to the AOS page on leaf spot fungus. They recommend cutting off the leaves but I don't usually do that. Good luck.
Phyllosticta Leaf Spot

[King_of_orchid_growing:)]

I don't recommend cutting leaves on your plant with the current condition they're in either. Especially with the Pescatorea/Cochleanthes.

I'd use cutting off leaves as a second to last resort.