Phalaenopsis suddenly turned yellow
 

Phalaenopsis was repotted in April. It appeared to be growing well and establishing new roots. I watered it on Friday morning and by Sunday night the entire plant was turning yellow. There was no change in location of the plant. Any thoughts on what might have caused this?

I would like to know what this is also. I had this happen to phals in the past and they died afterward in a short time. I think it might be a virus but I am no expert

It appeared/spread way to fast for it to be virus. More likely bacterial or fungal, and maybe some water got caught in the base of a leaf and didn't dry out, despite watering in the morning. Not sure what you can do abou it.

The info you gave us is insufficient.
As the seasons are changing now, maybe it could be the cause....cold draft or something.
But that wouldn't be so quick....the only thing that I know of that could cause this fast damage is sun/light burn.
But again, this is just a wild guess.

It looks like sunburn to me and that happens very fast. You say there is no change in location but have you considered that as we get further into Fall/Winter that the sun is lower in the sky and may now be hitting the plant directly?

Thanks
 

Thank you all for your replies. The plant has not been moved but I did not consider the effects of the sun in the changing season. It is by a window. Could be the colder air too. The leaves are still firm and there is nothing on the underside of them. If it is sunburn will it continue to grow?

I can post another picture at a later date if anyone is curious how it progresses.

Thanks again.

I don't think that's sunburn. Notice how the yellowing seems to start at the "midrib" and progress outward.

You mentioned cold temperatures; how cold has the plant gotten?

Ray,
The temperature in the house was down to 60 / 62 degrees while I was away for the weekend.
Thanks.

That doesn't sound like it should be too much of an issue by itself, but if there was a root issue already going on, that might have tipped the scale the wrong way, especially if the root system was in a moist medium.

Here’s a couple better pictures. It looks even worse today. The leaves look spotted.

Dp you have a photo of the whole plant, with pot and all?

Here’s a picture as it sits.

I think that's too cold, especially if it was cold and wet. Sometimes they tolerate it, but I would prevent it. I think those leaves are dead and will soon fall off.

Thank you. Sadly you are probably right. Always sad to lose a plant.

Hybrid Phals are warm-growing plants. They would prefer to be above 75 F / 24C at all times, and they thoroughly enjoy it much warmer. People get away with cool winter temperatures but it's risky.

The last photo is eloquent, if you kept the plant in the strong sun with cold nights I think she should look like that.

I had this happen to one of mine too. When I pulled back the sheaths of the dropped leaves, the crown had rotted. I think I may have got some water in the crown on the last watering and that combined with the lower temperatures due to the change in seasons lead to rot setting in.

I was surprised since this was one of my indoor Phals and those that I summer outside are getting hit with low 50s (Fahrenheit) at night and are still fine. Cold tolerance seems to vary a lot by background. I have 3 Phals that I never had to bring in last winter: they stood up to lows into the low 40s and high 30s fine while another suffered severe cold damage once temps got below 50.