Draining was poor, which was one reason I was going to move it into a pot to start development. We also had a few deep freezes, and I had no good protection for the trees. U normally mulch them in, but since we moved into an apartment while the new house is built I couldn't do much. They get no rain, as they are in the apartment patio, I hand water them. The rootpouch it was in was set in a larger pot surrounded by perlite, about 1 - 1.5" thick all around it. None of my trees are below the water table, as I grow them in above ground beds, so all the water flushes out of the bags at all times. when I had them in the ground I watered them 1-3 times a day depending on the weather. I never had any issue with any of my trees with root rot. Not even the ones that I intentionally leave inside water. Bald Cypress and tiger bark ficus included.
There were several reason that could have contributed to the trees demise. I think it was a combination of the removal from the grow bed in early December and the deep freeze in January. Not sure if the winged insect was a termite, I didn't see any holes or debris from them.