Black spot leaves - Phyllosticta?

[Fredmax]

Hi,

I've lost a plant recently that arrived with these black spots within a month, it seemed to explode out of nowhere with a virus that rapidly spread across the plant.

I purchased another, and it arrived with very similar markings that have the hallmarks of the last plant and suspect it's going to trigger at some point.

I've googled and got some results for Phyllosticta which doesn't sound good. Would any Vanda growers be familiar to know if the picture is the disease mentioned?

Thanks

[Ray]

There is no way to accurately diagnose from a photo.

I no longer grow vandas (no greenhouse and no room), but had dozens previously, and saw such spotting on occasion. It never spread nor resulted in a dead plant.

I suspect that the rapid decline is more related to a weakness in the culture than in the disease alone.

[SouthPark]

Fred ------ if the plant is stuck inside a container for a while, then there could possibly be some negative impact ----- things growing on the leaf etc.

Potting the vanda into some airy media, and always providing good temperature and lighting level and gentle air-flow across the leaves and through the media can really cut down on assumed fungal issues.

Hard to say what the spotting is due to right now. The main thing is that it doesn't spread. And if it does spread significantly, and assuming the orchid doesn't have any element deficiencies ------- then maybe need to apply some treatment ----- like systematic treatment for whatever could be behind that spotting.

Another approach is to ask the seller whether they get the same issue. The seller may provide some clues too.

From the look of that particular pic ------ the plant appears to look ok. Some spotting is definitely not unusual like that.

If that were my orchid ------ I would just take it out of that glass container, and pot it into chunky bark ...... or scoria -- into good drainage pot. And have some gentle air-flow.

[estación seca]

It can be very difficult to tell without looking under a microscope. I agree with Ray; Vandas usually have all sorts of spots.

[Fredmax]

Here is another pic showing the black spots better, also the old plant which you can see a few of the same black spots on the right leaf, there were many more on the prior leaves. I'm just suspect as I have around 30 Vandas and this is the only plant (Vanda Boonyarit Little Flame) with these markings and similar creasing.

I will enquire with the Nursery as their plants are always robust, but thought I'd get your opinions.

[Orchid Whisperer]

The diamond-shaped black spots are characteristic of Phyllosticta.

Find the St. Augustine Orchid Society website. It has a good section on plant diseases, and information on chemicals you can use to treat them. Look for a table of chemicals used to treat diseases, find a chemical that works on Phyllosticta. You may need to order appropriate fungicides online if you can't find locally.

Edited and added later: Fredmax, I was posting from my phone, noted when I was on my computer that you are in Australia (sorry I didn't notice before). In that case, please interpret my "appropriate fungicides" (above) to mean not only appropriate to control the disease, but also approved by your local authorities.

Calcium supplementation also helps suppress many diseases. Provide calcium along with the fungicide.

[Fredmax]

Originally Posted by Orchid Whisperer

The diamond-shaped black spots are characteristic of Phyllosticta.

Thank you for the advice, the images I saw on the St Augustine article Image Viewer drew parallels to what I've got.

I think I've purchased every fungicide available here in Aus -Phosacid, Bayer Octave ($300!), Mancozeb, Liquid Copper, Zaleton, Physan and more.... in my ongoing battles with Fungi and Bacteria and applied a couple to the last plant. My greatest concern is the virus spreading and whether the plant should be binned or put on an isolated windowsill away from the others.

[SouthPark]

Hi Fred ----- just going by the pic alone ----- is does the orchid grow near that location where it is shown in the pic?

One thing is ----- some crease/folding seen in one of the leaves could possibly indicate dehydration ----- not major, but slight dehydration. That's just by looks only.

Also, gentle air-movement in the growing area can cut down on fungal growth. Have you tried orchid-safe copper spray onto all the leaves? If not, then could even try that.

[Orchid Whisperer]

Fred, in your latest post you mentioned virus. I see what is probably a fungal disease, rather than a virus, which you can really only diagnose through testing.

It probably would be a good idea to separate the plant to keep from spreading the disease. Growing outdoors is an option if it is possible for you.

[Fredmax]

Originally Posted by Orchid Whisperer

Fred, in your latest post you mentioned virus. I see what is probably a fungal disease, rather than a virus,

I got confirmation from the Qld seller that he had a fungal disease some years back and these marks were the left over results. Also that Phyllosticta typically does not kill a plant, but may weaken it and that I may have left the Vanda too wet in cool temps without air circulation - quite possible.

I will look to remove it from the vase and put it outside, unfortunately Winter came back with 12c/6c yesterday and the next few days, I just took those pics at that location, the plant usually sits in the sunroom until it warms up, which the other Vanda's are doing ok in.

Incidentally the Vanda's that are flowering for me are the ones in bark, so I'm wondering if that may be a better medium for my dry climate than growing bare root in a vase.