Black spots/patches on cymbidium leaves

[mexicowpants]

Originally Posted by LizB88

I agree with Sonya, it seems that too much water has been sitting on the plants and not enough air flow.

Thanks for your input, it seems I was right about it being too much water. The air flow they have is great, however - a constant breeze day and night. Curse the humidity here, rainy season sucks.

Originally Posted by LizB88

My is give then a good flush with some diluted brown Listerine

Never heard of that before now, seems we only get the blue/green stuff here in Mexico. Are there any other alternatives? We have an anti-fungal powder (Captan) which we use when transplanting / making divisions -- would that be adequate?

Originally Posted by LizB88

For the 3rd picture, it does not look like a cym to me

It's an epidendrum; we have a couple of these mildly affected, too - would rubbing alcohol be best for these, too?

Thanks ever so much for your help

[estación seca]

Originally Posted by mexicowpants

(Re: Brown Listerine)
Never heard of that before now, seems we only get the blue/green stuff here in Mexico. Are there any other alternatives? We have an anti-fungal powder (Captan) which we use when transplanting / making divisions -- would that be adequate?

The antifungal in the Listerine would be the 27% ethanol. It also contains tiny amounts of other alcohols and methyl salicylate. This stuff is added to make the product bad-tasting so people won't drink it to get an ethanol buzz. This doesn't stop confirmed winos, and generic Listerine is some of the cheapest ethanol available in the US.

The eucalyptol, menthol etc. also make it smell like medicine - an example of the placebo effect. The formulations in the US show the same ingredients for the different colors.

Captan is a decent fungicide. It may wash off in the rain.

Many people use powdered cinnamon as an antifungal. I know canela is widely available in Mexico. It would also wash off in the rain.

A lot of high-rain areas in the tropics and subtropics feature many native plants with leaf damage from fungus. Often it doesn't seem to injure the plant much beyond appearance. If the spots on your plants don't progress you might want to think about whether you want to treat at all. If you decide to treat, start with less toxic treatments.

I'm even more concerned about antifungal toxicity to me than pesticide toxicity to me.