Which is better fungicide: copper or sulfur?

[Roberta]

Some orchid genera are sensitive to copper preparations such as Phyton 27, others are fine with it. I don't remember which ones are harmed by copper, so I mostly don't use it. Brown leaf tips on Cymbidiums probably not fungal... Salt buildup from fertilizer and/or hard water will cause the brown tips. It's important to flush the pots at least every 3rd or 4th watering, and let the water run through the pots. Some Cyms have more of an issue with salt build-up than others. But fungicide isn't going cure that one...

---------- Post added at 08:45 PM ---------- Previous post was at 08:44 PM ----------

Originally Posted by silken

That's what I have heard. I was also told some Dens don't like imidacloprid which is the systemic pesticide used for scale.

Never heard that about imidacloprid... have never had a Dendrobium problem with it.