Suspicious dark leaf spots on several orchids.

[BrassavolaStars]

Hello All,

While bringing my orchids into the greenhouse for the fall (probably too early as unfortunately, it is still getting into the 90s outside), I noticed that several of my plants have dark spots on the leaves.

I think that the spots developed on the patio during the late summer but I cannot be sure as some may have had spots when I bought them.

The spots seem to be affecting primarily a Zygopetalum and Oncidiums (a Trichopilia). This is the reason the spots did not concern me originally because both of these genera are known for hideous spotted foliage (especially zygos)

Recently, I have noticed spotting on an Aeranthes, a Dendrobium kingianum, and a Coelogyne. the Aeranthes is especially worrying as the spots are on the new leaf.

The spots on the Trichopilia and the Aeranthes look like fungal spots to me. I am not so sure about the other spots or how to treat these spot if they are fungal.

What should I do? If the spots are not going to hurt the plants, I would prefer to wait for new leaves.

I also have a myriad of fungicides including Aliette at my disposal.

[SouthPark]

Do you have fungal treatments, such as mancozeb, and cleary's 3336 ? I would just park these orchids in some nice shade and apply a treatment - just in case, and monitor the situation - as in see if there become more spots, or larger patches. Me too. I have a few different fungicides, which I generally didn't need to use for saving a plant (except for 1 single case with an incoming mailed plant) ------ but definitely have treatments on standby.

[Dollythehun]

Ditto South Park. I'm least concerned about the first two. I've started using Ray's newly renamed Concentric Ag once a month after an initial soak).

[WaterWitchin]

Not sure what your weather was like this year BStars, but if anything like it's been here in Kansas, it's been a primo year for that kind of spotting when putting plants outside for the summer. Tons of rain, very hot, and extremely humid. Around first part of July I even started running a fan outside...never done that before.

I'd use a fungicide/bactricide (sp?) on them, or the ConAg Dolly mentions (double strength at least first go-round) once a week for three weeks. And as SouthPark says... watchfully wait. Make sure you're not getting water from one splashed against the other as well, when watering.

Also, were they my plants, if I had leaves that looked absolutely awful, I'd go ahead and cut them back where possible. But that's just me...

[Ray]

The existing damage won't be repaired, but with either a fungicidal treatment or the use of a probiotic like Concentric Ag's Inocucor Garden Solution that the last two ladies have recommended, you won't see more.

I'll tack on a clarification of the probiotic's name:

The original company was Inocucor. Their product was Garden Solution. They expanded tremendously and renamed the company Concentric Ag. Because of state product registrations all being under the Inocucor name, it has remained "Inocucor Garden Solution" on the labels. They're in the process of getting new registrations, and as soon as California is finalized, the product will be called "Synergro".

[Dollythehun]

Do you suppose taxonomists work for Concentric Ag?

[Roberta]

Originally Posted by Dollythehun

Do you suppose taxonomists work for Concentric Ag?