What's Happening to My Catt Leaves?

[c123anderson]

Hi everyone! I have some leaf browning on two of my Cattleyas. If anyone has any thoughts on why and treatment/what to do, I'd be grateful for advice and thoughts.

The first three pictures are my Cattleya Hawaiian Wedding Song 'Virgin'. The first image is when I first received the plant a couple of months ago. The next two images are its current state. The images all show some leaf damage, but the leaf has yellowed a lot over the last few days.

I received C. Hawaiian Wedding Song 'Virgin' as a cutting while repotting. The plant had been treated (and then monitored by me) for armored scale. The last time I treated this plant for pests has been about 1 month ago. This was a spray with Enstar II and spot check with rubbing alcohol.

The next four pictures are my Cattleya gaskelliana. The first image is when I repotted it almost 1 month ago. The next few images show the damaged leaf with the last image showing it closer. The leaf, like the other plant, had been "okay" up to about a few days ago.

I received C. gaskelliana about 1 month ago from a closing nursery. It had scale, too. I treated it for scale and have kept it isolated a been monitoring it. This plant had been treated for pests by me and was last treated several weeks ago. Treatment included Sevin soak and spray, repotting in fresh media with new pot, Enstar II spray, and spot treatment with rubbing alchol.

I'm not sure why one leaf seems to be suddenly browning. In the case of the C. Hawaiian Wedding Song, the leaf already had some damage from an unknown source.

Plants are grown indoors. Checked daily or every other day for pests (so far, none after treatments). Temps range from 68F to 73F. Humidity is 40%-60%. Light is through opaque west-facing window with bright (filtered) afternoon sun. Light in this region of US is from 5 am to 8:30 pm -- about 15-16 hours per day right now.

Does anyone have any thoughts as to why the leaves are browning? Should I remove them? I check them to see if they have separated and are falling off on their own, but, so far, no. Should I be worried?

I believe this may be just stressed plants. Both have new growths (you can see the C. gaskelliana's in at least one of the images) and have green eyes which I'm monitoring for more new growth.

And, I appreciate the feedback. I've just recently found I enjoy Cattleya alliance plants and have been acquiring some more, including more from the out-of-business nursery. All my other plants are doing well, growing (some with happy sap), with no evidence of problems (bugs, fungus, disease, leaf damage, etc.). The leaf damage doesn't seem to be spreading to other plants or leaves on the same plant, either.

I'm just not sure how or if I should address or worry about this.