Bark spalling

[VUgearhead]

Guys, I don't know what is causing this on my honeybell tangelo.

First I noticed it on an exposed root. The bark on top just curled up and popped off. At first I thought it was due to sunburn as the canopy is not protecting this area. So I mulched it.

Now, I have noticed a fist sized area on the trunk doing the same thing. I would not think it would be sunburn here as it is better protected.

I have not found any disease descriptions that mention bark spalling like this.

Does anyone have any ideas?

TIA

[Citradia]

Slime mold flux disease infected one of my wild crabapples and now is killing a redbud tree. I noticed discoloration of patches of bark on the crab near where a major branch broke near trunk and death spread over a year systemically throughout the tree with dieback noted in canopy until I had to remove tree. Redbud is huge and green but loosing some small branches and big sections of bark on trunk popping off with noted wet-looking dark discoloration of bark. Extension agent told me no cure for it. Just have to clean pruners with bleach water solution between cuts. Don't know why red bud got it since I don't prune it. Crab got infected because I failed to prune out busted branch near trunk; couldn't reach it well since wild tree so thorny. Maybe your tree got infected from mower damage on exposed root?  Hopefully yours isn't slime mold. Can you post pic?

[VUgearhead]

Okay, I guess the bark spalling is just a symptom of end stage HLB. Took a closer look at it. Saw ACP's all over and their nymphs. Not sure why I hadn't noticed them before. What I thought was nutrient deficiency on the leaves now looks more like the disease mottling.

Tree has been in decline for a few years. I thought it had been due to my neglect, probably was. Anyway, tree will be coming out tomorrow.

[Citradia]

Sorry for your loss Vugearhead.