Cattleya dry rot

[NEslipper]

This has been a problem cattleya for me, it came as a bareroot division last year and took a while to get established (the box got stuck in transit during a heatwave and several plants in the order showed signs of extreme heat stress). While the other plants have since recovered and are growing fine, this one has never been particularly vigorous, although it did have a beautiful surprise bloom this year. I have tested it for CymMV and ORSV using the Agdia strips and it is negative, but I noticed at some point that it has this dry rot on the undersides of some of the leaves. The plant originally came from a very warm and humid climate, but I grow indoors in the northeast U.S. so my humidity is generally extremely low, and I almost never have any issues with rots/fungus. I feel like this is something that may have been latent in the plant and was brought on by the stress of division, extreme heat during shipping, and adapting to a new environment. The rot is extremely slow moving, and it mostly affects the older growths, although there is a small spot on the newest growth as well. I can see lots of green root tips in the pot now that it's spring, so I'm wondering if this is something the plant might outgrow since the newer growths seem less affected? Or should I be treating it aggressively?

Spots on the underside of the oldest leaf:

The largest spots on an older leaf:
A small spot on the newest leaf that penetrates from top to bottom:

 

[Ozpaph]

thats not rot, just dead tissue. Probably from extreme dehydration.

 

[monocotman]

I agree with Ozpaph, it’s not rot And probably tissue death due to the problems in shipping. I find potting new catts into as tiny a pot as possible with sphagnum is a good way to get them going.

 

[Karp60]

My second guess could be a sun burn….maybe between sheets of shadecloth or a hole …

 

[Ray]

Reminds me a bit like an acidovorax (pseudomonas) infection, which would lead me to try a copper-based treatment.

 

[tomp]

Reminds me a bit like an acidovorax (pseudomonas) infection, which would lead me to try a copper-based treatment.

Ray
which formulation do you recommend?

 

[Ray]

I don't think it really matters. I carry Southern Ag Liquid Copper, but Phyton 27 and others are just as good.

 

[NEslipper]

Thanks all for the responses! I suppose even if it’s damage from heat/shipping there could still be a secondary infection, so it probably wouldn’t hurt to treat it per Ray’s suggestion. Since I grow in my home, I generally try to avoid harsh chemicals, but I’ll look into a copper-based spray.

 

[richgarrison]

Wonder what is happening down in the pot…. Is there any active root growth or any new active ‘eyes’?

 

[Ray]

Since I grow in my home, I generally try to avoid harsh chemicals, but I’ll look into a copper-based spray.

Treat outdoors. Let dry. Bring back in.