Euphorbia obesa sunburned or sick?

Gilbert, AZ(Zone 9b)

Hi everyone,

My euphorbia obesa has recently developed some light brown "indented" scabs in linear forms along its upper crown. I live in Phoenix, AZ and I leave it out in the summer with patio blinds for shading during afternoon heat. Could the indented scabs be the results from sunburned, disease or overwatered? I water every 7-10 days, but it had been receiving more water due to monsoons

Thumbnail by Flyingsaucer Thumbnail by Flyingsaucer
Decatur, GA

My Euphorbias have the same corky marks. I don't know what might cause it but nothing I seem to do make a difference one way or the other.
Nice plant btw.

Thumbnail by helenchild Thumbnail by helenchild Thumbnail by helenchild
Reno, NV(Zone 6b)

All mine are doing the same thing and it seems the older the plant, the more brown spots it has. As long as the spots aren't mushy and the new growth is green, I think you are okay.

Thumbnail by DaisyPlantLady Thumbnail by DaisyPlantLady Thumbnail by DaisyPlantLady
Baja California, Mexico(Zone 11)

To add to the chorus, I think the brown tissue is not a concern. My Euphorbias have brown spots and it seems to be a cosmetic issue more than anything (and to some extent unavoidable).

One thing that strikes me, though, is that the spots on your plant are only on one side, and they all started at about the same age (imagine a line or "V" down from the tubercles all located about the same distance from the center). Which would suggest to me that there may have been an event or injury at some point in the recent past, and you are just now realizing its results. Does that make any sense? Maybe impact or too much sun or moisture, something like that. This is all hypothetical of course, as these considerations usually are.

Gilbert, AZ(Zone 9b)

Wow, thank you everyone.
Baja_Costero you had some great points. I believe it was the result of a sunburned event as we had a few consecutive days of scorching heat over of 110F in AZ last week. Corking usually occur at the oldest and lowest part of the cactus, so this would most likely be sunburned.

Found some really good info that can help diagnose cactus problems:

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