Guignardia advice?

[Roberta]

Originally Posted by MDBuch

Thanks Roberta! Well, I’ll definitely have to get a large mounting of two phals on a big branch inside before it gets any colder!

Hang it in the shower...

[estación seca]

I agree with Roberta. The sun has been lowering and you've had a hot spell. The plants haven't been getting as much light as they might like, and now the low, hot sun shone through the window and burned them. This can happen in only 5-10 minutes, if sun shines on a leaf that hasn't seen any sun.

[MDBuch]

Good to know, thank you both!

[Selmo]

I would go with the sunburn diagnosis over guignardia too. Guignardia feels rough like sandpaper and is caused by the leaf surface staying wet for extended periods of time. Leaves are usually infected but show no symptoms until they are watered on cloudy days, or late in the afternoon during cold weather when plant is under stress. Increasing the light level and air movement and monthly fungicide treatments are fairly effective at preventing guignardia.

[MDBuch]

So here’s that same plant again. Taken just this evening. These do look like burn even moreso now, but I just don’t see how this is the only one affected.

Any ideas?

[Ray]

In my opinion, that looks nothing like sunburn.

With sunburn, the tissue overheats and dies, soon turning black, and then into a brittle, parchment-like texture with clearly defined edges against the unaffected tissue.

That is an infection of some sort.

[katrina]

I agree with Ray...sunburn would be crispy brown by now. I've learned this one the hard way...more times than I care to admit.

I'm leaning toward something bacterial but diagnosis is hard enough in person...forget about doing it via pics most of the time. Personally, I'd cut the affected leaves and cut back far enough that you're into green, healthy tissue. For those with only small dots/spots, watch and be ready to cut. For those like the one in your most recent pic...I'd cut and I'd do it now.

I'm also convinced your problem is, at least in part, stemming from a lack of light. 4' from a west or south window is still pretty dim and while it might be sufficient for a phal part of the year, on it's own, it's not going to be enough light for any plant in the medium to high light categories, any time of the year. Work on improving the light situation...gradually...so you don't burn them from to much light, too soon.

[MDBuch]

Thanks guys, I guess I have more cutting to do.
I was really hard-pressed to see how just the one plant was getting it.

What would you guys suggest if the whole leaf is turning? Or if it’s most of the leaves on the plant?

[katrina]

Originally Posted by MDBuch

Thanks guys, I guess I have more cutting to do.
I was really hard-pressed to see how just the one plant was getting it.

What would you guys suggest if the whole leaf is turning? Or if it’s most of the leaves on the plant?

If it's the whole leaf...I'd remove it back to the pbulb.
If, when I cut back to the pbulb, if the pbulb looks affected, I would remove it. If the majority of the plant's leaves are showing the same, I'd just pitch the plant. But, that's me.

If you want to try and save it...remove all the affected tissue(s), and then isolate the plant. Some people like to save/rescue plants so I get it...it might recover, or it might not...either way if it's quarantined away from the healthy plants then you should be safe from any possibility of it spreading to the rest of your collection. This is all assuming it's something that's contagious and not just a weakness/illness due to some cultural issue but I usually go 'better safe than sorry' route.

[MDBuch]

Thanks Katrina. Yeah, I’ll have to see how it does. I’m starting to see a plant pitching in my future with this one!😫