Oncidium Twinkle....or is it a leopard? Spotted leaves and burnt tips

[MJG]

This is my Oncidium Twinkle that I bought in a cellophane bag at the Maui airport. I posted a NoID thread for this one a couple of weeks ago and got an answer in record time. In that post I included a picture of how the orchid looked 2 years after I bought it. (Below)

Many years later the orchid looks bad! As you can see, spotted leaves and fried leaf tips. When a new growth starts it looks great, but soon becomes spotted.

I've tested it for cymv and orsv -- negative. I've changed the lighting, cut back on the fertilizer, tried totally eliminating the fertilizer to no avail. I divided it a couple of years ago and the division has the same issues.

Could this be orchid fleck virus or a culture issue? Or??

[rbarata]

Closer photos of the leaves would be helpful.
Burnt tips can be too much fertilizer.

[SouthPark]

I agree with rbarata about the possibility of too much fertiliser hanging around in the pot or around the roots ----- or maybe even on leaves sometimes.

They say it draws water out of the plant in some way, and the leaf tips are generally the first to get affected by that sort of thing.

The spotting in twinkles ------ where growers just get it by default ----- appears to be a typical thing, and no cause for alarm. My twinkles have that spotting too. Not sure what it is due to though. No apparent adverse affects on the growing though.

My twinkles - sharry baby and fragrance fantasy - never get wet leaves. Air movement is good too in the growing area. Definitely not concerned about it after knowing that pretty much everyone else sees this sort of thing with their twinkles. But will be great to understand what the cause is - the mechanisms behind it. Eg. if inherited, then what's actually happening to cause the spots.

[MJG]

Hmmm. I thought that when I stopped fertilizing for many months there shouldn't be new growths forming burnt tips. But I had not considered that fertilizer might be hanging around in the roots or pot. That's a helpful explanation. I haven't repotted this orchid very frequently.

This plant is a very vigorous grower and flowerer. It doesn't behave like a diseased plant.

Here are a couple of leaf close-ups fyi.

[SouthPark]

MJG .... thanks for those close-ups! The patches appear to be larger than mine, and my plants have dark spots .... not brown.

If you have mancozeb, agri-fos etc, then maybe could try spraying a bit with those.

Even if the orchid might not have nutrient deficiency - sometimes growers have to provide magnesium and/or calcium treatments for good health.

If good gentle air-movement is provided, and leaves kept dry ------- just to see what happens, then maybe some good difference could be made too. But maybe you're providing those conditions already ------ so only just mentioning it!

Oh yeah ....... true. If salts accumulated in the media, then that can hang around in there. Could try a repot of one into fresh media and see what happens too.

[MJG]

Hmmm, again. Good thoughts. I certainly feel like I should try a fungicide, but have never used one. When you have an orchid with a fungus problem, how often/how many times should you treat it?

About calcium and magnesium....I have been blindly using the same orchid food for years. Recently I began reading about orchid fertilizer and nutrition and I actually read ALL of the ingredients in my orchid food. It contains no calcium or magnesium. I started supplementing just a couple of weeks ago. It's too soon to see if that's been part of the problem. If it is, I'm already heading in the right direction.

I did -- finally -- just repot. I also am careful to keep water off the leaves.

Thanks for all of the advice!

[SouthPark]

Originally Posted by MJG

Hmmm, again. Good thoughts. I certainly feel like I should try a fungicide, but have never used one. When you have an orchid with a fungus problem, how often/how many times should you treat it?

With those fungicides, just the usual precaution like spray when not very windy, and not when it's really sunny and hot ...... so maybe early in the morning is good.

Most of the time, just once is probably enough. And sometimes it may be necessary to rotate the fungicides .... as in try one to see if it is suitable or works for a particular case. Then next time use some other kind. And not use the same one every time - to avoid creating resistant strains of fungus. Whether this rotation really works or not ------ I don't know! But sort of makes sense.

Anyway - there are the systematic fungicides that get inside the plant and offers a more thorough cleanup of whatever it is targeting - like agri-fos and cleary's 3336 (thiomyl). And then there are non-systematic ones like mancozeb, and copper sprays are non-systematic too.

I think that copper sprays can actually kill some bacteria too - aside from killing some fungus. But copper is non-systematic. And some people say copper can harm some thin-leaved orchids and some dendrobiums.

[Dollythehun]

I just tossed two Twinkles because of how bad they looked. They were flowering machines but ugly. I think it's typical for most Oncidiums to have (varying degrees) of imperfect foliage. If I start again, I'll try to repot yearly.

[rbarata]

You will find a good resource of info here.
Some of the photos look like yours. The first thing that came to my mind was that they see the leaves of my Cymbs.
Your symptoms are, in their vast majority, fungal with a few spots that looks bacterial.
I would start with a fungicide, increase air flow and reduce humidity.

[KingKong]

I would recommend changing the media.
Bad leaves can be an indicator that something is not right in the root zone.
Cut away any roots that don't feel firm (brown is usually a good indicator but not a definite sign the root is bad)

Otherwise too strong light seems to make spotting worse but it is probably due to the roots not being able to keep up with the light provided so I would inspect the roots first, if they are in bad shape then provide less light till the roots recover.

Be very sparing with nutes, even tap water can cause salt build up if it has too high ppm.

Feed when you feel like leaves are too light of a colour or when in active growth but very sparingly. Too little feed is always better than too much.

Ps: adding mag and calc is good if you main nutrient lacks it but getting the ratio right is tricky, I would switch main nute otherwise you could end up feeding too much mag and calc and cause even more issues.