Physan 20 vs Thiomyl?

[vlhart]

Hi guys--

I don't know much at all about fungicides and insecticides and the like, so I'm wondering how, in general, you go about using certain ones.

Specifically Physan 20 and Clearys Thiomyl. These are the two that it seems people use the most. I've recently purchased both and am wondering how people use them. When do you use Physan 20 (on a plant, not just to sterilize surfaces/tools) and when would you use Thiomyl? How interchangeable are they? Do you use either of them preventatively?

And more specifically: I just got a Tolumnia red berry that appears to have a mild case of guignardia/"Thai disease," and an otherwise very healthy-looking Dendrobium micro chip that has one or two well-defined black spots on the leaves. Wondering how to treat both.

Thanks for any tips or advice! I feel like I'm on here asking after a new disease or pest or "spot" each week...Of course I'm buying a new plant just about every week...

[orchidsarefun]

I prefer Thiomyl as its a systemic. I don't use it often at all and try to go with alternative methods ( like Inocucor as a preventative ).

I don't know if you have seen this website -very useful
Orchid Pests, Orchid Diseases

I used to use it as a preventative but I consequently found that using a fungicide kills the beneficial stuff too and sometimes that's worse. Prevention is definitely better than the cure. Have you tried 3% hydrogen peroxide or even 70% rubbing alcohol directly swabbed on the spots ?

[vlhart]

Thanks for the info--and yes I look at that site a lot.

And I'll definitely try alcohol on the micro chip's spots. Haven't tried anything yet as I just got it.

[orchidsarefun]

also cinnamon made into a paste with a bit of water and rubbed on any cut also works wonders - if leaf ends start turning brown, you cut the offending parts off and rub the cut part with the cinnamon powder. It was the only thing that worked on one of my paphs.

[vlhart]

Is that for the guignardia? Only the slightest bit of the tips are brown.

I only noticed the more obvious clusters of spots in streaks today. But I did notice when I bought the Tolumnia that it had evenly spaced little brown spots on all of the leaves. Because the leaves themselves are that darker reddish color they actually looked kind of like natural coloring--still do. Also because of the coloring on the leaves I'm only just noticing that the tips are fading towards yellow.

I once tried cutting the dried end of an otherwise healthy looking vanda leaf and putting cinnamon on...and then the next day the leaf turned yellow and dropped...