Black marks on leaves of Odontioda Sturbic Purple

[fosterpapillon]

Does anybody have any suggestions as to what these black marks signify on the leaves of an Odontioda Sturbic Purple? Even the most recent new shoot has them.

[Leafmite]

I don't know but I will give you a link that will hopefully be helpful.

http://staugorchidsociety.org/PDF/Or...ySueBottom.pdf

[fosterpapillon]

Thanks for that - an excellent web site. My suspicion is that the problem is due to extremely cold conditions - my plants live on an open verandah covered with clear plastic sheeting and we've had a few close-to-zero mornings over the last couple of months. That's a bit chilly for Odontioda.

michael

[silken]

Originally Posted by fosterpapillon

Thanks for that - an excellent web site. My suspicion is that the problem is due to extremely cold conditions - my plants live on an open verandah covered with clear plastic sheeting and we've had a few close-to-zero mornings over the last couple of months. That's a bit chilly for Odontioda.

michael

That could well be the cause then. I find many of my Oncidium type do get spots, even when not chilled. If they were chilled, then all the more chance to spot. Just keep an eye on it to make sure it isn't spreadying. Or you could spray it with an anti-fungal/anti-bacterial treatment like Physan if you have it.

[fosterpapillon]

Thanks silken. I'll isolate it and hit it with an anti-fungal and see what happens.

michael

[estación seca]

I've read orchids can do this when water much warmer or colder than the leaves hits them.

[fosterpapillon]

Not likely, given that this is the only problematic one out of a hundred or more, all of which are watered at once. But thanks for the thought.

michael

[silken]

I always hear that my Oncidium spots are caused from water on the leaves. But no water ever touches my plants. I use a watering can with a long narrow spout to make very sure of that. I still get spots.

However, I do think in some cases it can be the cause of spots on leaves. more than just Oncidiums.

[fosterpapillon]

So are all oncidiums and their relatives seriously spotted in the wild? Serious question, not joking.

michael

[estación seca]

I want to know this about Oncidiums, too. I haven't seen them in the wild, but I've seen other genera. Almost all the orchids I've seen in the wild looked extremely beat up, including the ones loaded with beautiful flowers. I mean spots galore, holes, brown and black patches, big bites missing, old dead parts.