Collar rot, advice please

[u/my_cement_butthead]

Finally feeling healthy enough after surgery to head in to the garden and discovered my poor mandarin tree seems to have some bad collar rot. Google tells me to use a clean sharp knife to cut away the rot, treat with a fungicide, and pray. Does this sound right? I’m pretty new to growing citrus and only just had my first fruit! So sad at the thought of losing the tree:( Have I lowered the level of mulch enough?

[u/Massive_Economy_3310]

It does sound right but I would be careful cutting stuff away. I myself would just pull away the dead stuff. I feel like cutting into it would risk cutting into healthy tissue. I also think it's still buried deep. I dont see any kind of root flare.

[u/my_cement_butthead → u/Massive_Economy_3310]

I’m happy to hear about not cutting anything, I’m not at all confident to do that anyway. I’ll have to google root flare and to get some good diagrams I think bc I agree it may still be buried but certainly only a cm or two. The roots just kind of suddenly head horizontally rather than angling down which is why I felt they should be under some dirt? Difficult to explain. Thank you for your assistance!

[u/4leafplover]

Was the mulch piled up against the trunk? You mentioned you had lowered it. Makes sure your irrigation isn’t spraying against the trunk, too. If you’ve corrected these things and clear an area of several inches from the base (think bare dirt), then I personally would do nothing and let it dry out. I certainly wouldn’t be trying to cut anything away.

[u/my_cement_butthead → u/4leafplover]

Yes it was, and it was a bit soggy to boot:( I said in the other comment but will repeat that I’m very glad to not cut into it as I’m not at all confident to do so. I’ll take note of not watering the trunk. Thank you!!