New Cattleya Leaves Distorted

[Leisurely]

I am hoping that one of the Cattleya experts can diagnose my problem.

Accordian leaves on Oncidium types are indicitive of too little water. I am having something happen with my Cattleya leaves that I cannot diagnose. When the new growth starts, the sheathing material appears to be too snug for the leaf, resulting in the leaf having a vertical fold. The sheath has an opening, as you can see in the pictures, that allows water to enter and it sits there and causes a fungus problem resulting in black rot.

I have never had this problem before and I have not changed my watering practices. I water about once per week and the pseudobulbs are nice and plump. It seems that the leaf grows faster than the sheathing which causes it to wrinkle. I am hoping someone can give me some advice.

Thanks!

[V_coerulea]

Your root system looks good from what I can see and I agree with you that it looks like the oncidium "accordian leaf" syndrome. However, I think the problem lies with the sheath structure and not the leaf. Slit the sheath with a razor and see if the leave is still young enough to expand to its usual shape and size. Peal the sheath open and see if it's a double sheath or thicker than usual. It's certainly not going to hurt the plant any. If it's happening on more than 1 plant I'd suspect an environmental problem. I'm not sure what exactly would cause the problem with a single plant. Sorry I can't be more specific.

[Leisurely]

Including minicatts, I probably have 250 plants and the same thing is happening with at least a quarter of them. If I can keep the fungus at bay the distorted leaf eventually grows to a normal state. I have lost new growth on several plants though because I didn't treat for fungus. I have also perfromed the razor blade surgery as you suggested and my hand wasn't as steady as I would have liked so I ended up cutting into the leaf a couple of times.

[V_coerulea]

Wow, a quarter of them!? I have it on about half a dozen but I attributed it to repotting when they weren't exactly ready for it. Sometimes you have to repot when you have the time whether the plant wants it or not. I probably have too many when you get that kind of attitude. I have 400 different varieities of catts and hybrids with about 1400 total catts from seedlings on up. If I had a quarter of them with folded leaf I don't know what I'd do. Could you attribute it to a new spray in the past month or so? Change in feeding regimen? I still think the problem lies with the sheath growing too thick, too dry, too something that doesn't allow the leaf to break through. Although I suppose it could be the leaf is not elongating fast enough before it starts to expand. Does it seem to be occurring mostly in a particular hybrid like Blc or Slc or Pot? We are past the equinox with shorter days and less growth time. I don't know. Now I'm just rambling.

[Doc G]

I have not had this problem with the few Catts I have grown, but I have had "pleating" or accordion leaves on Onc. and intergenerics. There are three causes of pleating, improper watering, improper light and improper humidity. I have solved pleating problems by giving plants more light as often as I have remembering to water on time. What it comes down to is the proper balance of the three.

If two of your plants are next to each other and one is growing differently, then you may need to look in the pot to spot what the difference, and problem, may be.

[Leisurely]

I think I will just chalk the problem up to an unknown cause because when the leaf finally matures it grows out of the twisted look and becomes normal. I will spray those affected plants with fungicide to prevent the fungus problem where water collects and just hope that it was something environmental that will not repeat. I suspect that the cause was the extremely high humidity we had here during the rainy season.