Catt - White Powder on Leaf

[msrebekahjane]

Hi all, I've lurked on this forum for awhile now. I live in the PNW and grew phals for 5-6 years and just recently acquired a couple of catts.

1. The Spanish Eyes x Oconee has a very fine white powder on the underside of the leaf.

2. Top of leaf has a little white near the top.

3. The Catt came from Odoms and I've had it for about three weeks now.

Appreciate any inputs/advice.

[msrebekahjane]

I did check the disease links and suggested posts but found nothing that looked similar.

[estación seca]

Did they arrive with this? The top of leaf view shows the plant is very dehydrated and wrinkled. When this happens relatively rapidly the waxy cuticle may separate from the leaf and leave white patches. I think that's what you see on the top.

The bottom white area may be the same. Mineral buildup from high-mineral water may cause that too, but if it developed in 3 weeks, I would lean to thinking it's due to dessication.

How are you watering it? How often?

[msrebekahjane]

Thx for reply. I was unfamiliar with the potting media and contacted seller, who advised it's Stalite. Schedule in FL was 1x week. I did not inspect closely on arrival, so if present then, I missed it.

I waited about two and a half weeks before watering, because the climate is quite different here.

I also assumed (poor outcomes in that word) that they'd probable gave it a good watering before it left. I'm putting it on a weekly schedule. Agree with wrinkling.

[estación seca]

Where do you live? Once a week may not be enough. Is it making a new growth now? Many vendors ship Catts dry, especially in Winter.

[msrebekahjane]

I live in the Pacific North West (PNW). It is making new growth, but the flower sheath it arrived with isn't looking hopeful. See my post on the repotting forum.

Even though we're pretty wet and cool, indoor humidity has a tough time getting above 35% during the day when heats on (Gas stove). Pops up during the night when things cool down..

[estación seca]

Cattleya water requirement depends on all the cultural factors: temperature, stage of growth, amount of light and humidity. A Catt pushing new growth shouldn't dry out for any length of time. I suspect you problems are related to the long dry spell.

If the new growth hasn't turned black it will probably do OK if you start watering now. When you water, first take note of how much it weighs Then thoroughly soak the medium by running water through the pot for a while. Take note of how much it weighs wet. Water again when it's approaching dry weight but not all the way there yet.

[msrebekahjane]

Interesting you mention weighing. Because Stalite was new to me, I thought maybe it would help to record weights as a guide to watering.

I've inserted the data I have which reflect I probably waited too long for that first watering. The rh column is for a catt in a 4" pot. Neither catt is up to shipping weight.

The plan is to wait a couple more days, then water and start weighing again. Weights are in grams.

Date Spanish Eyes + Oconee Amazing Magician
01/04/24 1078 384 Rec’d
01/06/24 1038 380
01/09/24 1015 376
01/11/24 1001 373
01/14/24 963 356
01/15/24 963 357
01/16/24 955 356
01/21/24 932 532 Watered
01/22/24 984 367